Home

Agilent 33250A User's Guide - Electrical and Computer Engineering

1. FREQuency lt frequency gt MINimum MAXimum Discrete Parameters Discrete parameters are used to program settings that have a limited number of values like BUS IMMediate EXTernal They have a short form and a long form just like command keywords You can mix upper and lower case letters Query responses will always return the short form in all upper case letters The following command uses discrete parameters SWEep SPACing LINear LOGarithmic Boolean Parameters Boolean parameters represent a single binary condition that is either true or false For a false condition the function generator will accept OFF or 0 For a true condition the function generator will accept ON or 1 When you query a boolean setting the instrument will always return 0 or 1 The following command uses a boolean parameter AM STATe OFF ON String Parameters String parameters can contain virtually any set of ASCII characters A string must begin and end with matching quotes either with a single quote or a double quote You can include the quote delimiter as part of the string by typing it twice without any characters in between The following command uses a string parameter DISPlay TEXT lt quoted string gt 245 Chapter 4 Remote Interface Reference Using Device Clear Using Device Clear Device Clear is an IEEE 488 low level bus message that you can use to return the function generat
2. FREQuency FREQuency VOLTage VOLTage SINusoid SQUare RAMP PULSe NOISe DC USER lt frequency gt MINimum MAXimum MINimum MAXimum lt amplitude gt MINimum MAXimum MINimum MAXimum VOLTage 0 FFSet lt offset gt MINimum MAXimum VOLTage 0 VOLTage HIGH VOLTage U VOLTage U UNCtion UNCtion UNCtion UNCtion UTPu UTPu ct ct LO LO PO PO 7 Sy SY UTPu UTPu ct ct UTPu UTPu ct ct UTPu UTPu OF Or SOOO OO rat Parameters FFSet MINimum MAXimum HIGH lt voltage gt MINimum MAXimum MINimum MAXimum LOW lt voltage gt MINimum MAXimum LOW MINimum MAXimum VOLTage RANGe AUTO OFF ON ONCI VOLTage RANGe AUTO Gl w NIT VPP VRMS DBM NIT SQUare DCYCle lt percent gt MINimum MAXimum SQUare DCYCle MINimum MAXimum RAMP SYMMetry lt percent gt MINimum MAXimum RAMP SYMMetry MINimum MAXimum OFF ON AD lt ohms gt INFinity MINimum MAXimum AD MINimum MAXimum Larity NORMal INVerted Larity C OFF ON C2 shown in bold are selected following a RST reset command 132 AM Commands Chapter 4 Remote Interface Reference SCPI Command Summary Pulse Configuration Commands see page 166 for more information PULSe PERiod lt seconds gt MINimum MAXimum PULSe PERiod MINimum MAXimum PULSe WIDT
3. To rack mount two instruments side by side order lock link kit 5061 9694 and flange kit 5063 9212 Be sure to use the support rails in the rack cabinet In order to prevent overheating do not block the flow of air into or out of the instrument Be sure to allow enough clearance at the rear sides and bottom of the instrument to permit adequate internal air flow 28 Front Panel Menu Operation Front Panel Menu Operation This chapter introduces you to the front panel keys and menu operation This chapter does not give a detailed description of every front panel key or menu operation It does however give you an overview of the front panel menus and many front panel operations See chapter 3 Features and Functions starting on page 53 for a complete discussion of the function generator s capabilities and operation e Front Panel Menu Reference on page 31 e To Select the Output Termination on page 33 e To Reset the Function Generator on page 33 e To Output a Modulated Waveform on page 34 e To Output an FSK Waveform on page 36 e To Output a Frequency Sweep on page 38 e To Output a Burst Waveform on page 40 e To Trigger a Sweep or Burst on page 42 e To Store the Instrument State on page 43 e To Configure the Remote Interface on page 44 30 Chapter 2 Front Panel Menu Operation Front Panel Menu Reference Front Panel Menu Reference This section gives an overview of the fron
4. ee E eee A ee Oe OD ee S a J roe owes a Ld J nee L L L L i L L P e e e e j TA Er fo mes Sweor Bwat 3 10 1 fies E 1 Graph Mode Local Key 7 Utility Menu 2 Menu Operation Softkeys 8 Instrument Help Topic Menu 3 Waveform Selection Keys 9 Output Enable Disable Key 4 Knob 10 Manual Trigger Key used for 5 Modulation Sweep Burst Menus Sweep and Burst only 6 State Storage Menu 11 Navigation Arrow Keys Note To get context sensitive help on any front panel key or menu softkey press and hold down that key The Front Panel Display at a Glance Menu Mode Mode Trigger Output Information Information Units Status Display Numeric Readout Icon Gated Infinite Phase Softkey Labels Graph Mode To enter the Graph Mode press the Parameter Parameter Name Value Frequency 0 000 Ba Signal ep ae Ground The softkey colors correspond to the waveform parameters Front Panel Number Entry You can enter numbers from the front panel using one of two methods Use the knob and arrow keys to modify the displayed number se X J SS te ify afe K Vie eX J A Fa Ss LS Use the numeric keypad and menu softkeys to select the units select the units by pressing a key below ar a 1 2 3 a MHz CANCEL WARNING The Rear Panel at
5. Chapter 7 Tutorial Frequency Sweep Frequency Shift Keying FSK FSK is similar to FM except the frequency alternates between two preset values The rate at which the output shifts between the two frequencies called the carrier frequency and the hop frequency is determined by the internal rate generator or the signal level on the rear panel Trig In connector Frequency changes are instantaneous and phase continuous The internal modulating signal is a square waveform with 50 duty cycle You can set the internal FSK rate from 2 mHz to 1 MHz Modulating Signal Modulated Carrier Frequency Shift Keying Frequency Sweep Frequency sweeping is similar to FM but no modulating waveform is used Instead the internal DSP sets the output frequency based on either a linear or logarithmic function In a linear sweep the output frequency changes in a constant hertz per second manner In a logarithmic sweep the output frequency changes in a constant octaves per second or decades per second manner Logarithmic sweeps are useful for covering wide frequency ranges where resolution at low frequencies would potentially be lost in a linear sweep You can generate a sweep using an internal trigger source or an external hardware trigger source When the internal source is selected the function generator outputs a continuous sweep at a rate determined by the sweep time specified When the external sourc
6. PULSe PERiod lt seconds gt MINimum MAXimum PULSe PERiod MINimum MAXimum Set the period for pulses Select a period from 20 ns to 2000 seconds The default is 1 ms MIN 20 ns MAX 2000 seconds The PER query returns the period of the pulse waveform in seconds e The specified period must be greater than the sum of the pulse width and the edge time as shown below The function generator will adjust the pulse width and edge time as needed to accommodate the specified period From the remote interface a Data out of range error will be generated and the period will be adjusted as described Period gt Pulse Width 1 6 X Edge Time 166 Chapter 4 Remote Interface Reference Pulse Configuration Commands e This command affects the period and frequency for all waveform functions not just pulse For example if you select a period using the PULS PER command and then change the function to sine wave the specified period will be used for the new function e Function Limitations If you change to a function whose minimum period is greater than that for a pulse waveform the period is adjusted to the minimum value allowed for the new function For example if you output a pulse waveform with a period of 50 ns and then change to the ramp function the function generator will automatically adjust the period to 1 us the lower limit for ramps From the remote interface a Settings conflict error will be ge
7. e View the last message displayed e View the remote command error queue e Get HELP on any key e How to generate a dc only voltage level e How to generate a modulated waveform e How to create an arbitrary waveform e How to reset the instrument to its default state e How to view a waveform in the Graph Mode e How to synchronize multiple instruments e How to obtain Agilent Technical Support 32 Chapter 2 Front Panel Menu Operation To Select the Output Termination To Select the Output Termination The Agilent 33250A has a fixed series output impedance of 50 ohms to the front panel Output connector If the actual load impedance is different than the value specified the displayed amplitude and offset levels will be incorrect The load impedance setting is simply provided as a convenience to ensure that the displayed voltage matches the expected load Navigate the menu to set the output termination Press the Output Setup softkey and then select the Load softkey DONE Select the desired output termination Use the knob or numeric keypad to select the desired load impedance or press the Load softkey again to choose High Z To Reset the Function Generator To reset the instrument to its factory default state press select the Set to Defaults softkey Press YES to confirm the operation For a complete listing of the instrument s power on and reset conditions see Factory
8. 154 Chapter 4 Remote Interface Reference Output Configuration Commands FREQuency lt frequency gt MINimum MAXimum FREQuency MINimum MAXimum Set the output frequency MIN selects the lowest frequency allowed for the selected function and MAX selects the highest frequency allowed The default is 1 kHz for all functions The FREQ query returns the frequency setting in hertz for the function currently selected Function Minimum Frequency Maximum Frequency Sine 1 wHz 80 MHz Square 1 wHz 80 MHz Ramp 1 wHz 1 MHz Pulse 500 wHz 50 MHz Noise DC Not Applicable Not Applicable Arbs 1 wHz 25 MHz e Function Limitations If you change to a function whose maximum frequency is less than that of the current function the frequency is adjusted to the maximum value for the new function For example if you are currently outputting an 80 MHz sine wave and then change to the ramp function the function generator will automatically adjust the output frequency to 1 MHz the upper limit for ramps From the remote interface a Settings conflict error will be generated and the frequency will be adjusted as described e Duty Cycle Limitations For square waveforms the function generator may not be able to use the full range of duty cycle values at higher frequencies as shown below 20 to 80 frequency lt 25 MHz 40 to 60 25 MHz lt frequency lt 50 MHz 50 frequency gt 50 MHz If you change t
9. Period HiLevel LoLevel 19 Chapter 1 Quick Start To Set a DC Offset Voltage To Set a DC Offset Voltage At power on the function generator outputs a sine wave with a dc offset of 0 volts into a 50Q termination The following steps show you how to change the offset to 1 5 mVdc 1 Press the Offset softkey The displayed offset voltage is either the power on value or the offset previously selected When you change functions the same offset is used if the present value is valid for the new function 2 Enter the magnitude of the desired offset Using the numeric keypad enter the value 1 5 3 Select the desired units Press the softkey that corresponds to the desired units When you select the units the function generator outputs the waveform with the displayed offset if the output is enabled For this example press MVpc the DC On softkey Press the Offset softkey to enter the desired voltage level 20 Chapter 1 Quick Start To Set the Duty Cycle To Set the Duty Cycle Applies only to square waves At power on the duty cycle for square waves is 50 You can adjust the duty cycle from 20 to 80 for output frequencies up to 25 MHz The following steps show you how to change the duty cycle to 30 Select the square wave function Press the Ew key and then set the desired output frequency to any value less than 25 MHz Press the Duty Cycle softkey The
10. To Configure the Remote Interface The instrument is shipped with both a GPIB IEEE 488 interface and an RS 232 interface Only one interface can be enabled at a time The GPIB interface is selected when the instrument is shipped from the factory GPIB Configuration 1 Select the GPIB interface DONE 2 Select the GPIB address Press the GPIB Address softkey and enter the desired address using the numeric keypad or knob The factory setting is 10 The GPIB address is shown on the front panel display at power on 3 Exit the menu Press the DONE softkey 44 Chapter 2 Front Panel Menu Operation To Configure the Remote Interface RS 232 Configuration Select the RS 232 interface DONE Set the baud rate Press the Baud Rate softkey and select one of the following 300 600 1200 2400 4800 9600 19200 38400 57600 factory setting or 115200 baud Select the parity and number of data bits Press the Parity Bits softkey and select one of the following None 8 data bits factory setting Even 7 data bits or Odd 7 data bits When you set the parity you are also setting the number of data bits Select the handshake mode Press the Handshake softkey and select one of the following None DTR DSR factory setting Modem RTS CTS or XON XOFF Exit the menu Press the DONE softkey 45 46 Features and Functions Features and Fun
11. Chapter 3 Features and Functions Output Configuration e Remote Interface Operation VOLTage lt amplitude gt MINimum MAXimum Or you can set the amplitude by specifying a high level and low level using the following commands VOLTage HIGH lt voltage gt MINimum MAXimum VOLTage LOW lt voltage gt MINimum MAXimum You can also use the APPLy command to select the function frequency amplitude and offset with a single command DC Offset Voltage The default offset is 0 volts for all functions Limits Due to Amplitude The relationship between offset voltage and output amplitude is shown below Vmax is the maximum peak voltage for the selected output termination 5 volts for a 50Q load or 10 volts for a high impedance load Voffset lt Vmax Yep If the specified offset voltage is not valid the function generator will automatically adjust it to the maximum dc voltage allowed with the amplitude specified Limits Due to Output Termination The offset limits are determined by the current output termination setting For example if you set the offset to 100 mVdc and then change the output termination from 50 ohms to high impedance the offset voltage displayed on the function generator s front panel will double to 200 mVdc and no error will be generated If you change from high impedance to 50 ohms the displayed offset will drop in half See Output Termination on page 57 for more informatio
12. Data out of range value clipped to upper limit The specified parameter is outside of the function generator s capability The function generator has adjusted the parameter to the maximum value allowed Example PHAS 1000 Data out of range value clipped to lower limit The specified parameter is outside of the function generator s capability The function generator has adjusted the parameter to the minimum value allowed Example PHAS 1000 Data out of range pulse edge time limited by period The specified edge time must fit within the specified period The function generator will adjust the edge time as needed to accommodate the specified period Data out of range pulse width limited by period value clipped to The specified pulse width must be less than the difference between the period and the edge time as shown below The function generator will adjust the pulse width as needed to accommodate the specified period Pulse Width lt Period 1 6 X Edge Time Data out of range pulse edge time limited by width value clipped to The specified edge time must fit within the specified pulse width as shown below The function generator will adjust the edge time as needed to accommodate the specified pulse width Edge Time lt 0 625 X Pulse Width 261 222 222 222 222 222 222 222 Chapter 5 Error Messages Execution Errors Data out of range period value clipped to
13. Key STATe OFF ON Key STATe Parameters shown in bold are selected following a RST reset command 134 Chapter 4 Remote Interface Reference SCPI Command Summary Sweep Commands see page 181 for more information FREQuency STARt STARt lt frequency gt MINimum MAXimum MINimum MAXimum STOP lt frequency gt MINimum MAXimum STOP FREQuency CENTer PAN SWEep 3S 55 PACing LINear LOGarithmic PACing MINimum MAXimum lt frequency gt MINimum MAXimum CENTer MINimum MAXimum SPAN lt frequency gt MINimum MAXimum S MINimum MAXimum IME lt seconds gt MINimum MAXimum IME MINimum MAXimum SWEep STATe OFF ON SWEep STATe TRIGger SOURce IMMediate EXTernal BUS TRIGger SOURce TRIGger SLOPe POSitive NEGative Trig In Connector TRIGger SLOPe OUTPut TRIGger SLOPe POSitive NEGative Trig Out Connector TRIGger SLOPe TRIGger OFF ON TRIGger MARKer FR EQuency lt frequency gt MINimum MAXimum MARKER FR MARKer 0 MARKer Parameters EFQuency MINimum MAXimum FF ON shown in bold are selected following a RST reset command 135 Chapter 4 Remote Interface Reference SCPI Command Summary Burst Commands see page 187 for more information BURSt MODE TRIGgered GATed
14. Numeric data not allowed A numeric parameter was received but a character string was expected Example DISP TEXT 123 Invalid suffix A suffix was incorrectly specified for a numeric parameter You may have misspelled the suffix Example SWE TIME 0 5 SECS Suffix not allowed A suffix is not supported for this command Example BURS NCYC 12 CYC Character data not allowed A discrete parameter was received but a character string or numeric parameter was expected Check the list of parameters to verify that you have used a valid parameter type Example DISP TEXT ON Invalid string data An invalid character string was received Check to see if you have enclosed the character string in quotation marks and verify that the string contains valid ASCII characters Example DISP TEXT TESTING the ending quote is missing 250 158 161 168 170 to 178 Chapter 5 Error Messages Command Errors String data not allowed A character string was received but is not allowed for this command Check the list of parameters to verify that you have used a valid parameter type Example BURS NCYC TEN Invalid block data Applies only to the DATA DAC VOLATILE command For a definite length block the number of bytes of data sent does not match the number of bytes that you specified in the block header For an indefinite length block an EOI End or Identify was received without an accompanying lt new line gt character
15. Settings conflict not able to sweep this function The function generator cannot generate a sweep using the pulse noise or de voltage functions Settings conflict not able to burst this function The function generator cannot generate a burst using the dc voltage function Settings conflict not able to modulate noise modulation turned off The function generator cannot generate a modulated waveform using the noise function The selected modulation mode has been turned off Settings conflict not able to sweep pulse sweep turned off The function generator cannot generate a sweep using the pulse function The sweep mode has been turned off Settings conflict not able to modulate de modulation turned off The function generator cannot generate a modulated waveform using the dc voltage function The selected modulation mode has been turned off 256 221 221 221 221 221 Chapter 5 Error Messages Execution Errors Settings conflict not able to sweep dc modulation turned off The function generator cannot generate a sweep using the dc voltage function The sweep mode has been turned off Settings conflict not able to burst dc burst turned off The function generator cannot generate a burst using the dc voltage function The burst mode has been turned off Settings conflict not able to sweep noise sweep turned off The function generator cannot generate a sweep using the noise function
16. 69 Chapter 3 Features and Functions Amplitude Modulation AM Modulation Depth The modulation depth is expressed as a percentage and represents the extent of the amplitude variation At 0 depth the output amplitude is half of the selected value At 100 depth the output amplitude equals the selected value e Modulation depth 0 to 120 The default is 100 e Note that even at greater than 100 depth the function generator will not exceed 5V peak on the output into a 50Q load e Ifyou select the External modulating source the carrier waveform is modulated with an external waveform The modulation depth is controlled by the 5V signal level present on the rear panel Modulation In connector For example if you have set the modulation depth to 100 then when the modulating signal is at 5 volts the output will be at the maximum amplitude When the modulating signal is at 5 volts then the output will be at the minimum amplitude e Front Panel Operation After enabling AM press the AM Depth softkey Then use the knob or numeric keypad to enter the depth e Remote Interface Operation AM DEPTh lt depth in percent gt MINimum MAXimum 70 Chapter 3 Features and Functions Amplitude Modulation AM Modulating Source The function generator will accept an internal or external modulation source for AM e Modulating source Internal or External The default is Internal e Ifyou select the External sourc
17. 92 Chapter 3 Features and Functions Burst Mode Burst Count The burst count defines the number of cycles to be output per burst Used in the triggered burst mode only internal or external source e Burst count 1 to 1 000 000 cycles in 1 cycle increments You can also select an infinite burst count The default is 1 cycle e When the Internal trigger source is selected the specified number of cycles is output continuously at a rate determined by the burst period setting The burst period defines the interval between bursts e When the Internal trigger source is selected the burst count must be less than the product of the burst period and the waveform frequency as shown below Burst Count lt Burst Period X Waveform Frequency e The function generator will automatically increase the burst period up to its maximum value to accommodate the specified burst count but the waveform frequency will not be changed e When the gated burst mode is selected the burst count is ignored However if you change the burst count from the remote interface while in the gated mode the function generator remembers the new count and will use it when the triggered mode is selected e Front Panel Operation To set the burst count press the Cycles softkey and then use the knob or numeric keypad to enter the count To select an infinite count burst instead press the Cycles softkey again to toggle to the Infinite softkey press to stop the w
18. Burst Mode e e 1 Allowed in the External Gated burst mode only 49 Chapter 3 Features and Functions Output Configuration Function Limitations If you change to a function whose maximum frequency is less than that of the current function the frequency is adjusted to the maximum value for the new function For example if you are currently outputting an 80 MHz sine wave and then change to the ramp function the function generator will automatically adjust the output frequency to 1 MHz the upper limit for ramps Amplitude Limitations If you change to a function whose maximum amplitude is less than that of the current function the amplitude is automatically adjusted to the maximum value for the new function This may occur when the output units are Vrms or dBm due to the differences in crest factor for the various output functions For example if you output a 5 Vrms square wave into 50 ohms and then change to the sine wave function the function generator will automatically adjust the output amplitude to 3 536 Vrms the upper limit for sine in Vrms Front Panel Operation To select a function press any key in the top row of function keys Press Ab currently selected To view the other arbitrary waveform choices press the Select Wform softkey DC On softkey Press the Offset softkey to enter the desired offset voltage level Remote Interface Operation FUNCtion SHAPe SINusoi
19. Overshoot Jitter rms Ramp Linearity Symmetry Arb Minimum Edge Time Linearity Settling Time Jitter rms N a 70 dBm floor wo a 75 dBm floor NG lt 8ns lt 5 1 of period 1 ns 0 01 525 ps 0 1 75 ps 20 0 to 80 0 40 0 to 60 0 50 0 fixed 20 00 ns to 2000 0 s 8 0 ns to 1999 9s 5 00 ns to 1 00 ms lt 5 100 ppm 50 ps lt 0 1 of peak output 0 0 to 100 0 lt 10ns lt 0 1 of peak output lt 50 ns to 0 5 of final value 30 ppm 2 5 ns A total of four waveforms can be stored Harmonic distortion at low amplitudes is limited by Spurious noise at low amplitudes is limited by Edge time decreased at higher frequency Chapter 8 Specifications Agilent 33250A Function Arbitrary Waveform Generator OUTPUT CHARACTERISTICS Amplitude into 50Q 10 mVpp to 10 Vpp 2 Accuracy at 1 kHz gt 10 mVpp Autorange On 1 of setting 1 mVpp Flatness sinewave relative to 1 kHz Autorange On lt 10 MHz 10 MHz to 50 MHz 50 MHz to 80 MHz Units Resolution Offset into 50Q Accuracy Waveform Output Impedance Isolation Protection 1 0 1 dB 2 0 2 dB 5 0 4 dB Vpp Vrms dBm High Level Low Level 0 1 mV or 4 digits 5 Vpk ac dc 1 of setting 2 mV 0 5 of amplitude 50 typical fixed gt 10 MQ output disabled 42 Vpk max to Earth Short circuit protected Overload relay
20. This generic message indicates that the waveform period has been limited to an upper or lower boundary Data out of range frequency value clipped to This generic message indicates that the waveform frequency has been limited to an upper or lower boundary Data out of range user frequency value clipped to upper limit This generic message indicates that the waveform frequency has been limited to an upper boundary due to the selection of the arbitrary waveform function APPL USER or FUNC USER command Data out of range ramp frequency value clipped to upper limit This generic message indicates that the waveform frequency has been limited to an upper boundary due to the selection of the ramp waveform function APPL RAMP or FUNC RAMP command Data out of range pulse frequency value clipped to upper limit This generic message indicates that the waveform frequency has been limited to an upper boundary due to the selection of the pulse waveform function APPL PULS or FUNC PULS command Data out of range burst period value clipped to This generic message indicates that the burst period has been limited to an upper or lower boundary Data out of range burst count value clipped to This generic message indicates that the burst count has been limited to an upper or lower boundary 262 222 222 222 222 222 222 Chapter 5 Error Messages Execution Errors Data out of
21. User s Guide Publication Number 33250 90001 April 2000 Copyright Agilent Technologies 2000 All Rights Reserved Agilent 33250A 80 MHz Function Arbitrary Waveform Generator Agilent 33250A at a Glance The Agilent Technologies 33250A is a high performance 80 MHz synthesized function generator with built in arbitrary waveform and pulse capabilities Its combination of bench top and system features makes this function generator a versatile solution for your testing requirements now and in the future Convenient bench top features 10 standard waveforms Built in 12 bit 200 MSa s arbitrary waveform capability Precise pulse waveform capabilities with adjustable edge time LCD color display provides numeric and graphical views Easy to use knob and numeric keypad Instrument state storage with user defined names Portable ruggedized case with non skid feet Flexible system features Four downloadable 64K point arbitrary waveform memories GPIB IEEE 488 interface and RS 232 interface are standard SCPI Standard Commands for Programmable Instruments compatibility Note Unless otherwise indicated this manual applies to all Serial Numbers The Front Panel at a Glance a j N g 3 S a Sine Squere eal Fee Noise Arb N ai i ees Sg Ne SEs E E ae LZ PN 2 Nee Va N SHE Agilent F arenon acs T Be liz Function Arbitrary Wavefbrm Generator eae OOO ZN
22. arb Arb Arb Mem 1 Mem2 Mem3 Mem4 The waveform is now stored in non volatile memory and is currently being output from the function generator The name that you used to store the waveform should now appear in the list of stored waveforms under the Stored Wform softkey 107 Chapter 3 Features and Functions Arbitrary Waveforms Additional Information on Arbitrary Waveforms e As a shortcut to determine which arbitrary waveform is selected press w A temporary message is displayed on the front panel e In addition to creating a new arbitrary waveform from the front panel you can also edit any existing user defined waveforms You can edit waveforms that were created either from the front panel or from the remote interface However you cannot edit any of the five built in arbitrary waveforms e Press the Edit Wform softkey to edit any of the arbitrary waveforms stored in non volatile memory or the waveform currently stored in volatile memory While editing an existing waveform please note the following interactions e Ifyou increase the cycle period some points could potentially match existing points The waveform editor will preserve the earliest points and remove all duplicates e Ifyou decrease the cycle period the waveform editor will remove all points that were previously defined beyond the new period e Ifyou increase the voltage limits there will be no change in the voltage levels of any existing
23. lt percent gt MINimum MAXimum The APPLy command automatically sets the symmetry to 100 59 Chapter 3 Features and Functions Output Configuration Voltage Autoranging In the default mode autoranging is enabled and the function generator automatically selects the optimal settings for the output amplifier and attenuators With autoranging disabled the function generator uses the current amplifier and attenuator settings e One advantage of disabling autoranging is to eliminate momentary disruptions caused by switching of the attenuators while changing amplitude However the amplitude and offset accuracy and resolution as well as waveform fidelity may be adversely affected when reducing the amplitude below the expected range change e Front Panel Operation Press and select the Output Setup softkey Then press the Range softkey again to toggle between the Auto and Hold selections e Remote Interface Operation VOLTage RANGe AUTO OFF ON ONCE The APPLy command overrides the voltage autorange setting and automatically enables autoranging Output Control You can disable or enable the front panel Output connector At power on the output is disabled When enabled the key is illuminated e Ifan excessive external voltage is applied to the front panel Output connector an error message will be displayed and the output will be disabled To re enable the output remove the overload from the Outp
24. Block data not allowed Data was sent to the function generator in definite length block format but this command does not accept this format Check to see if you have sent the correct data type with the command Example BURS NCYC 10 Expression errors The function generator does not accept mathematical expressions 251 211 223 221 221 221 Chapter 5 Error Messages Execution Errors Execution Errors Trigger ignored A Group Execute Trigger GET or TRG was received but the trigger was ignored Make sure that you have selected the proper trigger source and verify that the sweep or burst mode is enabled Too much data An arbitrary waveform was specified that contains more than 65 536 waveform points Verify the number of points in the DATA VOLATILE or DATA DAC VOLATILE command Settings conflict turned off infinite burst to allow immediate trigger source An infinite count burst is allowed only when the external or bus software trigger source is selected The burst count has been set to the maximum value 1 000 000 cycles Settings conflict infinite burst changed trigger source to BUS An infinite count burst is allowed only when the external or bus software trigger source is selected Sending the BURS NCYC INF command has automatically changed the trigger source from immediate to bus Settings conflict burst period increased to fit entire burst The number of cycles specifie
25. Data out of range trigger delay value clipped to upper limit The trigger delay is limited to a maximum of 85 seconds The trigger delay sets the time between the receipt of the trigger and the start of the burst waveform used in triggered burst mode only Data out of range trigger delay limited by length of burst value clipped to upper limit The sum of the specified trigger delay and the time required to complete the burst waveform must be less than the period of the burst 264 222 222 313 314 315 Chapter 5 Error Messages Execution Errors Data out of range duty cycle value clipped to The duty cycle is limited to values between 20 and 80 when the frequency is less than 25 MHz Duty Cycle 20 to 80 frequency lt 25 MHz 40 to 60 25 MHz lt frequency lt 50 MHz 50 frequency gt 50 MHz Data out of range duty cycle limited by frequency value clipped to upper limit The duty cycle is limited to 50 when the frequency is greater than 50 MHz Duty Cycle 20 to 80 frequency lt 25 MHz 40 to 60 25 MHz lt frequency lt 50 MHz 50 frequency gt 50 MHz Calibration memory lost memory corruption detected The non volatile memory used to store the function generator s calibration constants has detected a checksum error This error may be the result of a device failure or extreme conditions such as lightning or strong magnetic fields Save recall memory lost memo
26. Noise DC User AM FM Carrier e e e FSK Carrier Sweep Mode Burst Mode e e 1 Allowed in the External Gated burst mode only 153 Chapter 4 Remote Interface Reference Output Configuration Commands Function Limitations If you change to a function whose maximum frequency is less than that of the current function the frequency is adjusted to the maximum value for the new function For example if you are currently outputting an 80 MHz sine wave and then change to the ramp function the function generator will automatically adjust the output frequency to 1 MHz the upper limit for ramps From the remote interface a Settings conflict error will be generated and the frequency will be adjusted as described e Amplitude Limitations If you change to a function whose maximum amplitude is less than that of the current function the amplitude is automatically adjusted to the maximum value for the new function This may occur when the output units are Vrms or dBm due to the differences in crest factor for the various output functions For example if you output a 5 Vrms square wave into 50 ohms and then change to the sine wave function the function generator will automatically adjust the output amplitude to 3 536 Vrms the upper limit for sine in Vrms From the remote interface a Settings conflict error will be generated and the amplitude will be adjusted as described
27. PHAS command remote interface only The default is DEG The ANGL query returns DEG or RAD e From the front panel the phase offset is always displayed in degrees radians are not available If you set the phase offset in radians from the remote interface and then return to front panel operation you will see that the function generator converts the phase offset to degrees PHASe REFerence Immediately set the zero phase reference point without changing the output of the function generator This command does not change the phase offset as set with the PHAS command it only changes the phase reference This command does not have a query form PHASe UNLock ERRor STATe OFF ON PHASe UNLock ERRor STATe Disable or enable the function generator from generating an error if the phase lock is ever lost The default is OFF If the phase lock is lost and the error is enabled a Reference phase locked loop is unlocked error is generated The unlock error setting is stored in non volatile memory The STAT query returns 0 OFF or 1 ON 224 Chapter 4 Remote Interface Reference The SCPI Status System The SCPI Status System This section describes the structure of the SCPI status system used by the function generator The status system records various conditions and states of the instrument in several register groups as shown on the following page Each of the register groups is made up of sev
28. The GPIB address is displayed The function generator powers up in the sine wave function at 1 kHz with an amplitude of 100 mV peak to peak into a 50Q termination At power on the Output connector is disabled To enable the Output connector press the key If the function generator does not turn on verify that the power cord is firmly connected to the power receptacle on the rear panel the power line voltage is automatically sensed at power on You should also make sure that the function generator is connected to a power source that is energized Then verify that the function generator is turned on If you need further assistance refer to the Agilent 33250A Service Guide for instructions on returning the function generator to Agilent for service 15 Chapter 1 Quick Start To Adjust the Carrying Handle To Adjust the Carrying Handle To adjust the position grasp the handle by the sides and pull outward Then rotate the handle to the desired position I ee Nel Bench top viewing positions Carrying position 16 Chapter 1 Quick Start To Set the Output Frequency To Set the Output Frequency At power on the function generator outputs a sine wave at 1 kHz with an amplitude of 100 mV peak to peak into a 50Q termination The following steps show you how to change the frequency to 1 2 MHz Press the Freq softkey The displayed frequency is either the power on value
29. The sweep mode has been turned off Settings conflict pulse width decreased due to period For a pulse waveform the function generator will automatically adjust the waveform parameters in the following order as needed to generate a valid pulse 1 edge time 2 pulse width and then 3 period In this case the function generator has decreased the pulse width to accommodate the specified period the edge time is already at its minimum setting Settings conflict edge time decreased due to period For a pulse waveform the function generator will automatically adjust the waveform parameters in the following order as needed to generate a valid pulse 1 edge time 2 pulse width and then 3 period In this case the function generator has decreased the edge time to accommodate the specified period and preserve the pulse width setting 257 221 221 221 Chapter 5 Error Messages Execution Errors Settings conflict edge time decreased due to pulse width For a pulse waveform the function generator will automatically adjust the waveform parameters in the following order as needed to generate a valid pulse 1 edge time 2 pulse width and then 3 period In this case the function generator has decreased the edge time to accommodate the specified pulse width Pulse Width gt 1 6 X Edge Time Settings conflict amplitude changed due to function In some cases the amplitude limits are determined
30. These errors indicate that the specified relay is not being properly switched or the attenuator amplifier is not providing the expected attenuation or gain These self tests use the internal ADC to verify that the output path relays output amplifier hybrid 20 dB and output attenuators are operating properly 270 701 702 703 705 706 707 850 851 Chapter 5 Error Messages Calibration Errors Calibration Errors The following errors indicate failures that may occur during a calibration For more information on the calibration procedures see chapter 4 in the Agilent 33250A Service Guide Calibration error security defeated by hardware jumper The function generator s calibration security feature has been disabled due to the installation of a hardware jumper on the internal circuit board Calibration error calibration memory is secured A calibration cannot be performed when calibration memory is secured To unsecure the instrument use the CAL SEC STAT ON command with the correct security code Calibration error secure code provided was invalid The security code specified with the CAL SEC STAT ON command is invalid Calibration error calibration aborted The function generator will not accept configuration commands such as APPL SIN while performing a calibration Calibration error provided value is out of range The calibration value specified with the CAL VAL command is out of range
31. burst state on Arb Output output state on Arb Output output sync on Check_Errors For i 1 To 20 Arb Output trg Sleep 100 Next i MsgBox Triggered Burst vbOKOnly Turn OFF Output BNC Disable Sync BNC Select Function square 20kHz 1Vpp and OV offset 20 duty cycle Bus triggering Burst of 3 cycles per trigger Enable Burst Turn ON Output BNC Enable Sync BNC Routine checks for errors ey Send BUS trigger Wait 100msec 33250A Example r Download a 20 point Arbitrary waveform using ASCII Dim Arb_20 0 To 19 As Double Fill_array Arb_20 With Arb IO Write Command data volatile False Argument 0 Arb_20 Send End With Arb Output func user volatile Arb Output apply user 10e3 1 0 Check_Errors MsgBox Download a 20 point Arb waveform using ASCII vbOKOnly This example for GPIB only Dim Arb_6 Dim Length As Long Dim Command As Byte Arb_6 Array 2047 2047 2047 2047 Length I0Utils CreateIEEEBlock Arb_6 data dac volatile Command Arb I0 WriteBytes Length Command Arb Output apply user 5000 1 0 Check_Errors MsgBox Download a 6 point Arb waveform using Binary vbOKOnly Continued Allocate array of 20 reals Call routine to fill array Place command into buffer Place comma separated data into buffer Send command data Select downloaded waveform Output waveform 10kHz 1Vpp Routine checks for errors 33250A
32. command Therefore when the marker frequency is enabled and the sweep mode is also enabled the OUTP SYNC command is ignored 186 Chapter 4 Remote Interface Reference Burst Mode Commands Burst Mode Commands See also Burst Mode starting on page 89 in chapter 3 Burst Mode Overview The following is an overview of the steps required to generate a burst You can use burst in one of two modes as described below The function generator enables one burst mode at a time based on the trigger source and burst source that you select see the table below Triggered Burst Mode In this mode default the function generator outputs a waveform with a specified number of cycles burst count each time a trigger is received After the specified number of cycles have been output the function generator stops and waits for the next trigger You can configure the function generator to use an internal trigger to initiate the burst or you can provide an external trigger by pressing the front panel key by applying a trigger signal to the rear panel Trig In connector or by sending a software trigger command from the remote interface External Gated Burst Mode In this mode the output waveform is either on or off based on the level of the external signal applied to the rear panel Trig In connector When the gate signal is true the function generator outputs a continuous waveform When the gate signal goes false the curren
33. for Windows FLENN ME SUT UTE SEAT MU NNNARN ENEA ANAA TSU UTED PE UAE UTE AEA EREA R AIEI AEE I AEA A YE I IE ETE UU ETE EEE E E Copyright c 2000 Agilent Technologies All Rights Reserved LIS Agilent Technologies provides programming samples for illustration purposes only This sample program assumes that you are familiar with the programming language being demonstrated and the tools used to create and debug procedures Agilent support engineers can help answer questions relating to the functionality of the software components provided by Agilent but they will not modify these samples to provide added functionality or construct procedures to meet your specific needs You have a royalty free right to use modify reproduce and distribute this sample program and or any modified version in any way you find useful provided that you agree that Agilent has no warranty obligations or liability for any sample programs COR IU SALIENT UE TTT I ELUTE MT OCU OD A TEI A EI MR TE EIN TEI AEI IDE IE IAEA A PA YE PEENE A TEETE NEGA E UE SPAIN ee Agilent 33250A 80 MHz Function Arb Waveform Generator Examples Examples include Modulation Pulse Sweeping Burst and Status Checking Examples illustrate various uses of short long form SCPI Examples also illustrate enabling disabling output BNCs To view results on Scope set to Channel 1 Output BNC 50ohms
34. press the Trigger Setup softkey Then select the desired edge by pressing the Slope softkey 96 Chapter 3 Features and Functions Burst Mode e Remote Interface Operation TRIGger SOURce IMMediate EXTernal BUS Use the following command to insert a trigger delay TRIGger DELay lt seconds gt MINimum MAXimum Use the following command to specify whether the function generator triggers on the rising or falling edge of the Trig In connector TRIGger SLOPe POSitive NEGative See Triggering on page 98 for more information on triggering Trigger Out Signal A trigger out signal is provided on the rear panel Trig Out connector used with burst and sweep only When enabled a TTL compatible square waveform with either a rising edge default or falling edge is output from the Trig Out connector at the beginning of the burst When the Internal immediate trigger source is selected the function generator outputs a square waveform with a 50 duty cycle from the Trig Out connector at the beginning of the burst The frequency of the waveform is equal to the specified burst period When the External trigger source is selected the function generator automatically disables the trigger out signal The Trig Out connector cannot be used for both operations at the same time an externally triggered waveform uses the same connector to trigger the burst When the Manual trigger source is selected the f
35. signal goes low when the output frequency reaches the specified marker frequency The marker frequency must be between the specified start frequency and stop frequency You can use the Marker function to identify a notable frequency in the response of a device under test DUT for example you may want to identify a resonance To do this connect the Sync output to one channel of your oscilloscope and connect the DUT output to another channel Then trigger the oscilloscope with the rising edge of the Sync signal to position the start frequency on the left side of the screen Adjust the marker frequency until the falling edge of the Sync signal lines up with the interesting feature in the device s response You can then read the frequency from the front panel display of the 33250A ee prad Sync Output Es es Ee Se Os se jaaa DUT Output Sweep with Marker at DUT Resonance 314 Chapter 7 Tutorial Burst Burst You can configure the function generator to output a waveform with a specified number of cycles called a burst You can use burst in one of two modes N Cycle Burst also called triggered burst or Gated Burst N Cycle Burst An N Cycle burst consists of a specific number of waveform cycles 1 to 1 000 000 and is always initiated by a trigger event You can also set the burst count to Infinite which results in a continuous waveform once the function generator is triggered Sy
36. the function generator will automatically adjust the output amplitude to 3 536 Vrms the upper limit for sine waves in Vrms From the remote interface a Data out of range error will be generated and the amplitude will be adjusted as described Arbitrary Waveform Limitations For arbitrary waveforms the maximum amplitude will be limited if the waveform data points do not span the full range of the output DAC Digital to Analog Converter For example the built in Sinc waveform does not use the full range of values between 1 and therefore its maximum amplitude is limited to 6 087 Vpp into 50 ohms While changing amplitude you may notice a momentary disruption in the output waveform at certain voltages due to switching of the output attenuators The amplitude is controlled however so the output voltage will never exceed the current setting while switching ranges To prevent this disruption in the output you can disable the voltage autoranging feature using the VOLT RANG AUTO command see page 160 for more information The APPLy command automatically enables autoranging 147 Chapter 4 Remote Interface Reference Using the APPLy Command DC Offset Voltage For the offset parameter of the APPLy command you can substitute MINimum MAXimum or DEFault in place of a specific value for the parameter MIN selects the most negative dc offset voltage for the function and amplitude specified MAX se
37. 232 Interface Configuration If your computer has a 9 pin serial port with a male connector use the cable included with the function generator If you need an additional cable order the F1047 80002 cable which is part of the Agilent 34398A Cable Kit This cable has a 9 pin female connector on each end The cable pin diagram is shown below this is the pinout for the cable shipped with the 33250A For proper operation you must use an RS 232 cable with the same pinout as shown below a RS 232 Cable _ RS 232 Troubleshooting Here are a few things to check if you are having problems communicating over the RS 232 interface If you need additional help refer to the documentation that came with your computer e Verify that the function generator s RS 232 interface is selected GPIB is the default interface Then verify that the function generator and your computer are configured for the same baud rate parity and number of data bits Make sure that your computer is set up for 1 start bit and 1 stop bit these values are fixed on the 33250A e Verify that you have connected the correct interface cable and adapters Even if the cable has the proper connectors for your system the internal wiring may not be correct You can use the 34398A Cable Kit to connect the function generator to most computers e Verify that you have connected the interface cable to the correct serial port on your computer COM1 COM2 etc 2
38. 4 Remote Interface Reference System Related Commands DISPlay TEXT lt quoted string gt DISPlay TEXT Display a text message on the function generator s front panel display Sending a text message to the display overrides the display state as set by the DISP command The TEXT query reads the message sent to the front panel display and returns a quoted string e You can use upper or lower case letters A Z numbers 0 9 and any other character on a standard computer keyboard Depending on the number of characters you specify in the string the function generator will choose one of two font sizes to display the message You can display approximately 12 characters in a large font and approximately 40 characters in a small font An example is shown below DISP TEXT Test in Progress e While a message is displayed information relating to the output waveform such as frequency and amplitude is not sent to the front panel display DISPlay TEXT CLEar Clear the text message currently shown on the function generator s front panel display e Ifthe display is currently enabled DISP ON command the DISP TEXT CLEAR command will return the normal front panel display mode e Ifthe display is currently disabled DISP OFF command the DISP TEXT CLEAR command will clear the message but the display will remain disabled To enable the display send the DISP ON command press the key send the GTL Go T
39. AM to be enabled at the same time that sweep or burst is enabled When you enable AM the sweep or burst mode is turned off 171 Chapter 4 Remote Interface Reference Frequency Modulation FM Commands Frequency Modulation FM Commands See also Frequency Modulation starting on page 72 in chapter 3 FM Overview The following is an overview of the steps required to generate an FM waveform The commands used for FM are listed on the next page Configure the carrier waveform Use the APPLy command or the equivalent FUNC FREQ VOLT and VOLT OFFS commands to select the function frequency amplitude and offset of the carrier waveform You can select a sine square ramp or arbitrary waveform for the carrier pulse noise and dc are not allowed Select the modulation source The function generator will accept an internal or external modulation source Select the modulation source using the FM SOUR command For an external source you can skip steps 3 and 4 below Select the shape of the modulating waveform You can modulate the carrier with a sine square ramp noise or arbitrary waveform pulse and dc are not allowed Use the FM INT FUNC command to select the modulating waveshape Set the modulating frequency Set the modulating frequency to any value from 2 mHz to 20 kHz using the FM INT FREQ command Set the peak frequency deviation Set the frequency deviation to any value from 5
40. BURSt MODE BURSt NCYCles lt cycles gt INFinity MINimum MAXimum BURSt NCYCles MINimum MAXimum BURSt INTernal PERiod lt seconds gt MINimum MAXimum BURSt INTernal PERiod MINimum MAXimum BURSt PHASe lt angle gt MINimum MAXimum BURSt PHASe MINimum MAXimum BURSt STATe OFF ON BURSt STATe UNIT ANGLe DEGree RADian UNIT ANGLe TRIGger SOURce IMMediate EXTernal BUS Triggered Burst TRIGger SOURce TRIGger DELay lt seconds gt MINimum MAXimum TRIGger DELay MINimum MAXimum TRIGger SLOPe POSitive NEGative Trig In Connector TRIGger SLOPe BURSt GATE POLarity NORMal INVerted External Gated Burst BURSt GATE POLarity OUTPut TRIGger SLOPe POSitive NEGative Trig Out Connector TRIGger SLOPe TRIGger OFF ON TRIGger Parameters shown in bold are selected following a RST reset command 136 Chapter 4 Remote Interface Reference SCPI Command Summary Arbitrary Waveform Commands see page 198 for more information DATA VOLATILE lt value gt lt value gt DATA DAC VOLATILE lt binary block gt lt value gt lt value gt FORMat BORDer NORMal SWAPped Specify Byte Order FORMat BORDer DATA COPY lt destination arb name gt VOLATILE FUNCtion USER lt arb name gt VOLATILE FUNCtion USER FUNCtion USER FUNCtion DATA CATalog NVOLatile CATalog NVOLatile FR
41. CLS clear status command or when the power is cycled The errors are also cleared when you read the error queue The error queue is not cleared by an instrument reset RST command e Front Panel Operation Press and then select the topic entitled View the remote command error queue topic number 2 Then press the SELECT softkey to view the errors in the error queue As shown below the first error in the list i e the error at the top of the list is the first error that was generated Remote Interface Command Errors 113 Undefined header 224 Illegal parameter value DONE e Remote Interface Operation SYSTem ERRor Reads one error from the error queue Errors have the following format the error string may contain up to 255 characters 113 Undefined header 248 101 102 103 105 108 109 Chapter 5 Error Messages Command Errors Command Errors Invalid character An invalid character was found in the command string You may have used an invalid character such as or in the command header or within a parameter Example TRIG SOUR BUS Syntax error Invalid syntax was found in the command string You may have inserted a blank space before or after a colon in the command header or before a comma Example APPL SIN 1 Invalid separator An invalid separator was found in the command string You may have used a comma instead of a colon semicolon or blank spa
42. Calibration error signal input is out of range The internal analog to digital converter ADC has determined that the signal applied to the rear panel Modulation In connector is out of range Calibration error setup is invalid You have specified an invalid calibration setup number with the CAL SET command Refer to the Agilent 33250A Service Guide for more information on the calibration procedures Calibration error setup is out of order Certain calibration setups must be performed in a specific sequence in order to be valid Refer to the Agilent 33250A Service Guide for more information on the calibration procedures 271 770 781 781 782 784 785 Chapter 5 Error Messages Arbitrary Waveform Errors Arbitrary Waveform Errors The following errors indicate failures that may occur during arbitrary waveform operation Refer to Arbitrary Waveform Commands on page 198 for more information Nonvolatile arb waveform memory corruption detected The non volatile memory used to store arbitrary waveforms has detected a checksum error The arbitrary waveform cannot be retrieved from memory Not enough memory to store new arb waveform use DATA DELETE The four non volatile memory locations already contain arbitrary waveforms To store another waveform you must first delete one of the stored waveforms using the DATA DELete command Not enough memory to store new arb waveform bad sectors Due to a hard
43. Configure the Remote Interface on page 44 118 Chapter 3 Features and Functions Remote Interface Configuration Remote Interface Selection The instrument is shipped with both a GPIB IEEE 488 interface and an RS 232 interface Only one interface can be enabled at a time When shipped from the factory the GPIB interface is selected e The interface selection is stored in non volatile memory and does not change when power has been off or after a remote interface reset e Ifyou select the GPIB interface you must select a unique address for the instrument The GPIB address is displayed on the front panel when you turn on the function generator e Ifyou select the RS 232 interface you must also set the baud rate parity and handshake mode for the function generator The interface selection is displayed on the front panel when you turn on the function generator e Front Panel Operation Press uiilty and then select the GPIB or RS 232 softkey from the I O menu See also To Configure the Remote Interface on page 44 e Remote Interface Operation SYSTem INTerface GPIB RS232 Refer to RS 232 Interface Configuration on page 219 for information on connecting the 33250A to a computer over the RS 232 interface 119 Chapter 3 Features and Functions Remote Interface Configuration Baud Rate Selection RS 232 You can select one of several baud rates for RS 232 operation When shippe
44. Default Settings on page 133 33 Chapter 2 Front Panel Menu Operation To Output a Modulated Waveform To Output a Modulated Waveform A modulated waveform consists of a carrier and a modulating waveform In AM amplitude modulation the amplitude of the carrier is varied by the amplitude of the modulating waveform For this example you will output an AM waveform with 80 modulation depth The carrier will be a 5 kHz sine wave and the modulating waveform will be a 200 Hz sine wave stokes stocked y 1 Select the function frequency and amplitude of the carrier Sine and then press the Freq Ampl and Offset softkeys to configure the carrier waveform For this example select a 5 kHz sine wave with an amplitude of 5 Vpp 2 Select AM iod and then select AM using the Type softkey Notice that a status message AM by Sine is shown in the upper left corner of the display 3 Set the modulation depth Press the AM Depth softkey and then set the value to 80 using the numeric keypad or the knob and arrow keys 34 Chapter 2 Front Panel Menu Operation To Output a Modulated Waveform 4 Set the modulating frequency Press the AM Freq softkey and then set the value to 200 Hz using the numeric keypad or the knob and arrow keys 5 Select the modulating waveform shape Press the Shape softkey to select the shape of the modulating waveform For this example select a
45. EYE DETE IE EE IE AEA IE VENE INTE TETE VE YE YE VE VEVE SEVE JEVE F 70 Agilent 33250A 80MHz Function Arb Waveform Generator Examples 80 90 Examples include Modulation Pulse Sweeping and Burst 200 Examples illustrate various uses of short long form SCPI 210 Examples also illustrate enabling disabling output BNCs 220 To view results on Scope set to 230 Channel 1 Output BNC 50ohms 50us div 200mV div 240 Channel 2 Sync BNC 50us div 500mV div trigger on Channel 2 250 260 BASIC for Windows examples for GPIB RS 232 270 k 3 30 00 280 290 GPIB Configuration 300 310 ASSIGN Fgen TO 710 GPIB ASCII data commands 320 ASSIGN Bin TO 710 FORMAT OFF GPIB Binary data 330 i 340 RS 232 Configuration uncomment these lines comment out GPIB lines 350 g 360 ASSIGN Fgen TO 9 RS 232 ASCII data commands 370 ASSIGN Bin TO 9 FORMAT OFF RS 232 Binary data 380 CONTROL 9 3 57600 57 6k Baud 390 CONTROL 9 473 8 bits no parity 2 stop bits 400 CONTROL 9 5 1 DTR on OUTPUT 410 CONTROL 9 12 16 DSR on ENTER 420 CONTROL 9 100 0 Turn OFF XON XOFF 430 COM Instrument Fgen Bin Global instrument addresses 440 g 450 Return 33250A to turn ON conditions 460 470 OUTPUT Fgen RST Default state of instrument 480 OUTPUT Fgen CLS Clear errors and status 490 Continued 278 Chapter 6 Application Programs Example BASIC for Windows 500 PRINT AM Modula
46. Example Download a 6 point Arbitrary waveform using Binary Create array Used to find total length of array Used to store total command sequence 2047 2047 TIOUtils_Short IIOUtils_BigEndian Download command and bytes Output waveform 5kHz l1Vpp 33250A Example 284 Chapter 6 Application Programs Example Microsoft Visual Basic for Windows A Using the Status Registers Arb Output apply sin 10e3 1 0 Arb Output trig sour bus Arb Output burst ncycles 50000 Arb Output burst stat on Arb Output ese 1 Arb Output sre 32 Check_Errors Arb Output trg opc Dim Stats As Integer Dim Done As Boolean Done False While Not Done Arb Output stb Arb Enter Stats If Stats And 64 Then Done True End If Wend MsgBox Done vbOKOnly 33250A cmdStart Enabled True End Sub Private Sub Form_Load Dim IdStr As String m_Count 1 Arb Output IDN Arb Enter IdStr Caption IdStr End Sub Sub Check_Errors Dim ErrVal 0 To 1 With Arb Output syst err Enter ErrVal While ErrVal 0 lt gt 0 lstErrors AddItem ErrVal 0 lstErrors Refresh Output SYST ERR Enter ErrVal Wend End With End Sub Continued om Sy SSS SNS 10kHz Sine wave 1Vpp Bus Trigger in Burst 50000 cycles x 0 1lms Turn ON burst mode Operation complete Operation complete Routine checks for Trigger burst OPC signals end of TRG Variable to store status Controls Wh
47. Function Arbitrary Waveform Generator WAVEFORMS Standard Waveforms Arbitrary Waveforms Waveform Length Amplitude Resolution Repetition Rate Sample Rate Filter Bandwidth Non Volatile Memory Sine Square Ramp Pulse Noise Sin x x Exponential Rise Exponential Fall Negative Ramp Cardiac DC Volts 1 to 64K points 12 bits including sign 1 uHz to 25 MHz 200 MSa s 50 MHz Four 64K waveforms FREQUENCY CHARACTERISTICS Sine Square Ramp Pulse Noise Gaussian Arb Resolution Accuracy Stability Aging 1 Hz to 80 MHz 1 Hz to 80 MHz 1 uHz to 1 MHz 500 uHz to 50 MHz 50 MHz bandwidth 1 uHz to 25 MHz 1 Hz except pulse 5 digits 0 3 ppm 18 C to 28 C 1 ppm 0 C to 50 C 1 ppm per 1 year SINEWAVE SPECTRAL PURITY Harmonic Distortion lt 3Vpp gt 3Vpp DC to 1 MHz 60 dBc 55 dBc 1 MHz to 5 MHz 57 dBc 45 dBc 5 MHz to 80 MHz 37 dBc 30 dBc Total Harmonic Distortion DC to 20 kHz Spurious non harmonic DC to 1 MHz 1 MHz to 20 MHz 20 MHz to 80 MHz Phase Noise 30 kHz band 10 MHz 80 MHz lt 0 2 0 1 mVrms 60 dBc 50 dBc 50 dBc 6 dBc octave lt 65 dBc typical lt 47 dBc typical SIGNAL CHARACTERISTICS Square Wave Rise Fall Time Overshoot Asymmetry Jitter rms lt 2 MHz gt 2 MHz Duty Cycle lt 25 MHz 25 MHz to 50 MHz 50 MHz to 80 MHz Pulse Period Pulse Width Variable Edge Time
48. Hz to 40 05 MHz limited to 550 kHz for ramps and 12 55 MHz for arbitrary waveforms using the FM DEV command Enable FM modulation After you have set up the other modulation parameters use the FM STAT ON command to enable FM 172 Chapter 4 Remote Interface Reference Frequency Modulation FM Commands FM Commands Use the APPLy command or the equivalent FUNC FREQ VOLT and VOLT OFFS commands to configure the carrier waveform FM SOURce INTernal EXTernal FM SOURce Select the source of the modulating signal The function generator will accept an internal or external modulation source The default is INT The SOUR query returns INT or EXT e Ifyou select the External source the carrier waveform is modulated with an external waveform The frequency deviation is controlled by the 5V signal level present on the rear panel Modulation In connector For example if you have set the deviation to 100 kHz using the FM DEV command then a 5V signal level corresponds to a 100 kHz increase in frequency Lower external signal levels produce less deviation and negative signal levels reduce the frequency below the carrier frequency FM INTernal FUNCtion SINusoid SQUare RAMP NRAMp TRIangle NOISe USER FUNCtion Select the shape of the modulating waveform Used only when the Internal modulation source is selected FM SOUR INT command You can use noise as the modulating waveshape but y
49. PRINT Using the Status Registers 1 OUTPUT Fgen apply sin 10e3 1 0 OUTPUT Fgen trig sour bus OUTPUT Fgen burst ncycles 50000 l OUTPUT Fgen burst stat on l OUTPUT Fgen ese 1 OUTPUT Fgen sre 32 l Check_errors l OUTPUT Fgen trg opc Chapter 6 Application Programs Example BASIC for Windows 10kHz Sine wave 1Vpp Bus Trigger in Burst 50000 cycles x 0 1ms 5s Turn ON burst mode Operation complete Operation complete Routine checks for Trigger burst OPC signals end of TRG enabled sets SRO errors Burst complete Request Status Byte Read Status Byte Test for Master Summary Bit is found Request Error message Error number Description If error 0 then exit Print Error Description Now wait for Operation Complete to signal 1 WHILE 1 OUTPUT Fgen stb ENTER Fgen Stb l IF BIT Stb 6 THEN PRINT Done STOP END IF END WHILE END 1 Subprogram to check for instrument errors 1 SUB Check_errors DIM Description 100 INTEGER Err_num COM Instrument Fgen Bin 1 Query the error queue until a 0 No Error WHILE 1 OUTPUT Fgen SYSTem ERRor 1 ENTER Fgen Err_num Description l IF NOT Err_num THEN SUBEXIT PRINT Err_num Description END WHILE SUBEND 281 Chapter 6 Application Programs Example Microsoft Visual Basic for Windows Example Microsoft Visual Basic for Windows Option Explicit D PB im m_Count As Integer rivate IOUtils As New
50. Set the starting phase of one instrument to 90 Then adjust the burst count on each instrument as needed for your application If continuous burst waveforms are required select an Infinite burst count on both instruments and enable manual triggering on the master In this example the trigger delay parameters become in effect system calibration constants Once established they keep the two instruments aligned in time even if their frequency or starting phase are changed Each time the master triggers the slave the two instruments are re synchronized If the power is cycled you can realign the instruments by restoring the previous trigger delays Note that different delay values may be required if a different pair of instruments is used or if different waveform functions are selected Gated Burst In the Gated burst mode the output waveform is either on or off based on the level of the external signal applied to the rear panel Trig In connector When the gate signal is true the function generator outputs a continuous waveform When the gate signal goes false the current waveform cycle is completed and then the function generator stops while remaining at the voltage level corresponding to the starting burst phase of the selected waveform For a noise waveform the output stops immediately when the gate signal goes false 317 318 Specifications Chapter 8 Specifications Agilent 33250A
51. System Related Commands 213 Interface Configuration Commands 218 RS 232 Interface Configuration 219 Phase Lock Commands 223 The SCPI Status System 225 Status Reporting Commands 235 Calibration Commands 239 An Introduction to the SCPI Language 241 Using Device Clear 246 Chapter 5 Error Messages Command Errors 249 Execution Errors 252 Query Errors 267 Instrument Errors 268 Self Test Errors 269 Calibration Errors 271 Arbitrary Waveform Errors 272 Chapter 6 Application Programs Introduction 276 Example BASIC for Windows 278 Example Microsoft Visual Basic for Windows 282 Example Microsoft Visual C for Windows 287 10 Contents Chapter 7 Tutorial Direct Digital Synthesis 295 Creating Arbitrary Waveforms 298 Square Waveform Generation 300 Pulse Waveform Generation 300 Signal Imperfections 302 Output Amplitude Control 304 Ground Loops 305 Attributes of AC Signals 307 Modulation 309 Frequency Sweep 312 Burst 315 Chapter 8 Specifications Frequency Characteristics 320 Sinewave Spectral Purity 320 Signal Characteristics 320 Output Characteristics 321 Modulation Characteristics 321 Burst 321 Sweep 321 System Characteristics 322 Trigger Characteristics 322 Clock Reference 322 Sync Output 322 General Specifications 323 Product Dimensions 324 Index 325 11 U9 U05 12 Quick Start Quick Start One of the first things you will want to do with your function g
52. TTL pulse with the specified polarity The trigger period must be greater than or equal to the specified sweep time plus 1 ms When the Manual or External source is selected the function generator outputs one sweep each time the front panel key is pressed Front Panel Operation Press the Trigger Setup softkey and then select the desired source by pressing the Source softkey To specify whether the function generator triggers on the rising or falling edge of the Trig In connector press the Trigger Setup softkey Then select the desired edge by pressing the Slope softkey Remote Interface Operation TRIGger SOURce IMMediate EXTernal BUS Use the following command to specify whether the function generator triggers on the rising or falling edge of the signal on the Trig In connector TRIGger SLOPe POSitive NEGative See Triggering on page 98 for more information 87 Chapter 3 Features and Functions Frequency Sweep Trigger Out Signal A trigger out signal is provided on the rear panel Trig Out connector used with sweep and burst only When enabled a TTL compatible square waveform with either a rising edge default or falling edge is output from the Trig Out connector at the beginning of the sweep When the Internal immediate trigger source is selected the function generator outputs a square waveform with a 50 duty cycle from the Trig Out connector at the beginning of the sweep The frequ
53. a Glance S ee pA 7 SA Sk X 10MHz In C Serat Number Label A Oe eee n 140VA Max wT Me meoile r C nts 7 j 1 B 1 I E Ne ome LSS ae Y 1 External 10 MHz Reference Input Terminal 5 Input External Trig FSK Burst Gate 2 Internal 10 MHz Reference Output Terminal Output Trigger Output 3 RS 232 Interface Connector 6 GPIB Interface Connector 4 External Modulation Input Terminal 7 Chassis Ground Use the e Select the GPIB or RS 232 interface see chapter 2 Select the GPIB address see chapter 2 e Set the RS 232 baud rate parity and handshake mode see chapter 2 For protection from electrical shock the power cord ground must not be defeated If only a two contact electrical outlet is available connect the instrument s chassis ground screw see above to a good earth ground In This Book Quick Start Chapter 1 prepares the function generator for use and helps you get familiar with a few of its front panel features Front Panel Menu Operation Chapter 2 introduces you to the front panel menu and describes some of the function generator s menu features Features and Functions Chapter 3 gives a detailed description of the function generator s capabilities
54. and any other character on a standard computer keyboard Depending on the number of characters that you specify the function generator will choose one of two font sizes to display the message You can display approximately 12 characters in a large font and approximately 40 characters in a small font 115 Chapter 3 Features and Functions System Related Operations e Remote Interface Operation The following command turns off the front panel display DISP OFF The following command displays a message on the front panel and turns on the display if currently disabled DISP TEXT Test in Progress To clear the message displayed on the front panel without changing the display state send the following command DISP TEXT CLEAR Number Format The function generator can show numbers on the front panel display with periods or commas for the decimal point and digits separator This feature is available from the front panel only uF 1 00 000 00 kHz mE 100000000 kHz C Ampl BROT set Ampl Period HiLevel LoLevel Period HiLevel LoLevel Decimal Point Period Decimal Point Comma Digits Separator Comma Digits Separator None e The number format is stored in non volatile memory and does not change when power has been off or after a remote interface reset When shipped from the factory a period is used for the decimal point and commas are used for the digits separator e g 1 000 000 00 kHz e Front P
55. and operation You will find this chapter useful whether you are operating the function generator from the front panel or over the remote interface Remote Interface Reference Chapter 4 contains reference information to help you program the function generator over the remote interface Error Messages Chapter 5 lists the error messages that may appear as you are working with the function generator Each listing contains enough information to help you diagnose and solve the problem Application Programs Chapter 6 contains several remote interface application programs to help you develop programs for your application Tutorial Chapter 7 discusses the fundamentals of signal generation and modulation techniques Specifications Chapter 8 lists the function generator s specifications If you have questions relating to the operation of the Agilent 33250A call 1 800 452 4844 in the United States or contact your nearest Agilent Technologies Office If your 33250A fails within three years of purchase Agilent will either repair or replace it free of charge Call 1 877 447 7278 in the United States and ask for Agilent Express or contact your local Agilent Technologies Office Contents Chapter 1 Quick Start To Prepare the Function Generator for Use 15 To Adjust the Carrying Handle 16 To Set the Output Frequency 17 To Set the Output Amplitude 18 To Set a DC Offset Voltage 20 To Set the Duty Cycle 21 To Conf
56. and then change the output termination from 50 ohms to high impedance the amplitude displayed on the function generator s front panel will double to 20 Vpp If you change from high impedance to 50 ohms the displayed amplitude will drop in half For more information see Output Termination on page 57 Limits Due to Units Selection In some cases the amplitude limits are determined by the output units selected This may occur when the units are Vrms or dBm due to the differences in crest factor for the various output functions For example if you output a 5 Vrms square wave into 50 ohms and then change to the sine wave function the function generator will automatically adjust the output amplitude to 3 536 Vrms the upper limit for sine waves in Vrms 52 Chapter 3 Features and Functions Output Configuration You can set the output amplitude in Vpp Vrms or dBm For more information see Output Units on page 56 You cannot specify the output amplitude in dBm if the output termination is currently set to high impedance The units are automatically converted to Vpp For more information see Output Units on page 56 Arbitrary Waveform Limitations For arbitrary waveforms the maximum amplitude will be limited if the waveform data points do not span the full range of the output DAC Digital to Analog Converter For example the built in Sinc waveform does not use the full range of values
57. any user defined waveforms non volatile FUNCtion USER FUNCtion Select the arbitrary waveform function and output the current arbitrary waveform When executed this command outputs the arbitrary waveform currently selected by the FUNC USER command see the previous page The selected waveform is output using the current frequency amplitude and offset voltage settings The FUNC query returns SIN SQU RAMP PULS NOIS DC or USER Use the APPLy command or the equivalent FREQ VOLT and VOLT OFFS commands to select the frequency amplitude and offset of the waveform The maximum amplitude will be limited if the data points do not span the full range of the output DAC Digital to Analog Converter For example the built in SINC waveform does not use the full range of binary values between 1 and therefore its maximum amplitude is 6 087 Vpp into 50 ohms If you select an arbitrary waveform as the modulating waveshape USER the waveform is automatically limited to 8K points Extra waveform points are removed using decimation 205 Chapter 4 Remote Interface Reference Arbitrary Waveform Commands DATA CATalog List the names of all waveforms currently available for selection Returns the names of the five built in waveforms non volatile memory VOLATILE if a waveform is currently downloaded to volatile memory and all user defined waveforms d
58. ata ata I fo oll ll AS tt os oO om Il Coo NN ODIADUOBWNEO Il S I oo Il Il PRR ooo Aa Sele 2oaaqqqQqqqgqgqgnga0 0a 0a 000 Il PREP OANA BUN Il Continued 288 Chapter 6 Application Programs Example Microsoft Visual C for Windows int main int argc char argv CoInitialize NULL int it char cmds 100 J try IIOManagerPtr IOMgr IIOPtr I00bj IIOUtilsPtr IOUtils IOUtils CreateInstance _ uuidof AgtUtilsObject General purpose counter Used to TOMgr CreateInstance __uuidof Agt IOManager store command string TOMgr gt ConnectToInstrument L COM1 Baud 57600 Handshake DTR_DSR Default state of instrument Clear errors and status Configure for Hi Z load 1MHz Sine 1Vpp OVdc offset Modulating signal Ramp Modulating 10kHz Modulation depth 80 Turn ON AM modulation Routine check for errors frequency Turn OFF AM modulation Configure for 50 ohm load 20kHz Sine 1Vpp OVdc Offset FM deviation 20kHz FM Modulation Freq 1kHz Turn ON FM modulation Routine check for errors Turn OFF FM modulation RS 232 Configuration uncomment line comment out GPIB line IOObj GPIB Configuration IOObj IOMgr gt ConnectToInstrument L GPIBO 10 Return 33250A to turn on conditions IOO0bj gt Output RST IOObj gt Output CLS AM Modulat
59. auto matically disables main output MODULATION CHARACTERISTICS AM Modulation Carrier Waveforms Modulating Waveforms Modulating Frequency Depth Source FM Modulation Carrier Waveforms Modulating Waveforms Modulating Frequency Peak Deviation Source FSK Carrier Waveforms Modulating Waveforms Internal Rate Frequency Range Source External Modulation Input Voltage Range Input Impedance Frequency Sine Square Ramp Arb Sine Square Ramp Noise Arb 2 mHz to 20 kHz 0 0 to 120 0 Internal External Sine Square Ramp Arb Sine Square Ramp Noise Arb 2 mHz to 20 kHz DC to 80 MHz Internal External Sine Square Ramp Arb 50 duty cycle square 2 mHz to 100 kHz 1 Hz to 80 MHz Internal External 5V full scale 10 kQ DC to 20 kHz BURST Waveforms Frequency Burst Count Start Stop Phase Internal Period Gate Source Trigger Source Trigger Delay N Cycle Infinite SWEEP Waveforms Type Direction Start F Stop F Sweep Time Trigger Marker ae Sine Square Ramp Pulse Noise Arb 1 Hz to 80 MHz 1 to 1 000 000 cycles or Infinite 360 0 to 360 0 1 ms to 500s External Trigger Single External or Internal Rate 0 0 ns to 85 000 s Sine Square Ramp Arb Linear or Logarithmic Up or Down 100 uHz to 80 MHz 1 ms to 500 s Single External or Internal Falling edge of Sync signal programmable Add 1
60. between 1 and therefore its maximum amplitude is limited to 6 087 Vpp into 50 ohms While changing amplitude you may notice a momentary disruption in the output waveform at certain voltages due to switching of the output attenuators The amplitude is controlled however so the output voltage will never exceed the current setting while switching ranges To prevent this disruption in the output you can disable the voltage autoranging feature as described on page 60 You can also set the amplitude with an associated offset voltage by specifying a high level and low level For example if you set the high level to 2 volts and the low level to 3 volts the resulting amplitude is 5 Vpp with an offset voltage of 500 mV For dc volts the output level is actually controlled by setting the offset voltage You can set the dc level to any value between 5 Vdc into 50 ohms or 10 Vdc into an open circuit See DC Offset Voltage on the following page for more information To select dc volts from the front panel press Wiity and then select the DC On softkey Press the Offset softkey to set the desired offset voltage level Front Panel Operation To set the output amplitude press the Ampl softkey for the selected function Then use the knob or numeric keypad to enter the desired amplitude To set the amplitude using a high level and low level press the Ampl softkey again to toggle to the HiLevel and LoLevel softkeys 53
61. buffers are full 3 Device Error 8 A self test cal or other device specific error has occurred see chapter 5 4 Execution Error 16 An execution error has occurred see chapter 5 5 Command Error 32 A command syntax error has occurred see chapter 5 6 Not Used 64 Not Used Returns 0 7 Power On 128 Power has been cycled on since the last time the event register was read or cleared 233 Chapter 4 Remote Interface Reference The SCPI Status System The Standard event register is cleared when e You execute the CLS command e You query the event register using the ESR command The Standard Event enable register is cleared when e You execute the ESE 0 command e You turn the power on and have previously configured the function generator to clear the enable register using the PSC 1 command Note that the enable register will not be cleared at power on if you have configured the function generator using the PSC 0 command 234 Chapter 4 Remote Interface Reference Status Reporting Commands Status Reporting Commands An application program is included in chapter 6 which shows the use of the Status System Registers See page 275 for more information Status Byte Register Commands See the table on page 227 for the register bit definitions STB Query the summary condition register in this register group This command is similar to a Serial Poll
62. burst period and frequency as shown below Select INF to generate a continuous burst waveform The NCYC query returns the burst count from 1 to 1 000 000 or 9 9E 37 for an infinite count e Ifthe Immediate trigger source is selected TRIG SOUR IMM command the burst count must be less than the product of the burst period and the waveform frequency as shown below Burst Count lt Burst Period X Waveform Frequency e The function generator will automatically increase the burst period up to its maximum value to accommodate the specified burst count but the waveform frequency will not be changed From the remote interface a Settings conflict error will be generated and the burst period will be adjusted as described e For sine and square waveforms frequencies above 25 MHz are allowed only with an infinite burst count e When the gated burst mode is selected the burst count is ignored However if you change the burst count while in the gated mode the function generator remembers the new count and will use it when the triggered mode is selected 190 Chapter 4 Remote Interface Reference Burst Mode Commands BURSt INTernal PERiod lt seconds gt MINimum MAXimum BURSt INTernal PERiod MINimum MAXimum Set the burst period for internally triggered bursts The burst period defines time from the start of one burst to the start of the next burst Select from 1 ps to 500 seconds The default is 10 ms MIN
63. by the output units currently selected This may occur when the units are Vrms or dBm due to the differences in crest factor for the various output functions For example if you output a 5 Vrms square wave into 50 ohms and then change to the sine wave function the function generator will automatically adjust the output amplitude to 3 536 Vrms upper limit for sine waves in Vrms Settings conflict offset changed on exit from dc function In the dc voltage function the voltage level is controlled by adjusting the offset voltage the current amplitude is ignored When you select a different function the function generator will adjust the offset voltage as needed to be compatible with the current amplitude setting 258 221 221 221 221 Chapter 5 Error Messages Execution Errors Settings conflict FM deviation cannot exceed carrier The carrier frequency must always be greater than or equal to the frequency deviation If you attempt to set the deviation to a value greater than the carrier frequency with FM enabled the function generator will automatically adjust the deviation to the maximum value allowed with the present carrier frequency Settings conflict FM deviation exceeds max frequency The sum of the carrier frequency and deviation must be less than or equal to the maximum frequency for the selected function plus 100 kHz 80 1 MHz for sine and square 1 1 MHz for ramp and 25 1 MHz for arbitrary wavefo
64. characters a Program mnemonic too long error is generated The VOLATILE parameter is optional and can be omitted Note that the keyword VOLATILE does not have a short form The following built in waveform names are reserved and cannot be used with the DATA COPY command EXP_RISE EXP_FALL NEG_RAMP SINC and CARDIAC If you specify one of the built in waveforms a Cannot overwrite a built in waveform error is generated The function generator does not distinguish between upper and lower case letters Therefore ARB_1 and arb_1 are the same name All characters are converted to upper case 203 Chapter 4 Remote Interface Reference Arbitrary Waveform Commands e Ifyou copy to a waveform name that already exists the previous waveform is overwritten and no error will be generated However you cannot overwrite any of the five built in waveforms e Up to four user defined waveforms can be stored in non volatile memory If memory is full and you try to copy a new waveform to non volatile memory a Not enough memory error is generated Use the DATA DEL command to delete the waveform in volatile memory or any of the four user defined waveforms in non volatile memory Use the DATA CAT command to list all waveforms currently stored in volatile and non volatile memory e The following statement shows how to use the DATA COPY command to copy the VOLATILE waveform into named
65. default Point 1 is set equal to the upper limit and Point 2 is set equal to the lower limit For this example set the upper limit to 3 0 V and the lower limit to 0 V C 0000 V Fw High f LowY Interp Init t Limit Limit Off fq Points Points Select the interpolation method Press the Interp softkey to enable or disable linear interpolation between waveform points this feature is available from the front panel only With interpolation enabled default the waveform editor makes a straight line connection between points With interpolation disabled the waveform editor maintains a constant voltage level between points and creates a step like waveform For this example turn on linear interpolation 104 Chapter 3 Features and Functions Arbitrary Waveforms 6 Set the initial number of waveform points You can create an arbitrary waveform with up to 65 536 64K points The waveform editor initially builds a waveform with two points and automatically connects the last point of the waveform to the voltage level of the first point to create a continuous waveform Press the Init Points softkey to specify the initial number of waveform points you can add or remove points later if necessary For this example set the initial number of points to 4 7 Start the point by point editing process Press the Edit Points softkey to accept the initial waveform settings and begin point by point editing The stat
66. displayed duty cycle is either the power on value or the percentage previously selected The duty cycle represents the amount of time per cycle that the square wave is at a high level note the icon on the right side of the display C Wo H Period HiLevel LoLevel Cycle Enter the desired duty cycle Using the numeric keypad or the knob select a duty cycle value of 30 The function generator adjusts the duty cycle immediately and outputs a square wave with the specified value if the output is enabled 38 0 LL Period HiLevel LoLevel 21 Chapter 1 Quick Start To Configure a Pulse Waveform To Configure a Pulse Waveform You can configure the function generator to output a pulse waveform with variable pulse width and edge time The following steps show you how to configure a 500 ms pulse waveform with a pulse width of 10 ms and edge times of 50 us 1 Select the pulse function Press the se key to select the pulse function and output a pulse waveform with the default parameters 2 Set the pulse period Press the Period softkey and then set the pulse period to 500 ms 00 00ms i Pulse Edge Period MES a E 3 Set the pulse width Press the Pulse Width softkey and then set the pulse width to 10 ms The pulse width represents the time from the 50 threshold of the rising edge to the 50 threshold of the next falling edge note the display icon Ampl MOT f seti Edge Period MIESEN MES
67. edge is output from the rear panel Trig Out connector at the beginning of the sweep Select POS to output a pulse with a rising edge or select NEG to output a pulse with a falling edge The default is POS The SLOP query returns POS or NEG e When the Immediate internal trigger source is selected TRIG SOUR IMM command the function generator outputs a square waveform with a 50 duty cycle from the Trig Out connector at the beginning of the sweep The period of the waveform is equal to the specified sweep time SWE TIME command e When the External trigger source is selected TRIG SOUR EXT command the function generator automatically disables the trigger out signal The rear panel Trig Out connector cannot be used for both operations at the same time an externally triggered sweep uses the same connector to trigger the sweep e When the Bus software trigger source is selected TRIG SOUR BUS command the function generator outputs a pulse gt 1 ps pulse width from the Trig Out connector at the beginning of each sweep OUTPut TRIGger OFF ON OUTPut TRIGger Disable or enable the trigger out signal When enabled a TTL compatible square waveform with the specified edge OUTP TRIG SLOP command is output from the rear panel Trig Out connector at the beginning of the sweep The default is OFF The TRIG query returns 0 OFF or 1 ON 185 Cha
68. enter the desired rate e Remote Interface Operation FSKey INTernal RATE lt rate in Hz gt MINimum MAXimum 80 Chapter 3 Features and Functions Frequency Shift Keying FSK Modulation FSK Source FSK source Internal or External The default is Internal When the Internal source is selected the rate at which the output frequency shifts between the carrier frequency and hop frequency is determined by the FSK rate specified When the External source is selected the output frequency is determined by the signal level on the rear panel Trig In connector When a logic low level is present the carrier frequency is output When a logic high level is present the hop frequency is output The maximum external FSK rate is 1 MHz Note that the connector used for externally controlled FSK waveforms Trig In is not the same connector that is used for externally modulated AM and FM waveforms Modulation In When used for FSK the Trig In connector does not have adjustable edge polarity Front Panel Operation After enabling FSK press the Source softkey Remote Interface Operation FSKey SOURce INTernal EXTernal 81 Chapter 3 Features and Functions Frequency Sweep Frequency Sweep In the frequency sweep mode the function generator steps from the start frequency to the stop frequency at a sweep rate which you specify You can sweep up or down in frequency and with either linear or log
69. equivalent FREQ VOLT and VOLT OFFS commands to select the frequency amplitude and offset of the waveform Download the waveform points into volatile memory You can download from 1 point a de signal to 65 536 64K points per waveform You can download the points as floating point values binary integer values or decimal integer values Use the DATA command to download floating point values from 1 0 to 1 0 Use the DATA DAC command to download binary integer or decimal integer values from 2047 to 2047 To ensure that binary data is downloaded properly you must select the order in which the bytes are downloaded using the FORM BORD command 198 Chapter 4 Remote Interface Reference Arbitrary Waveform Commands 3 Copy the arbitrary waveform to non volatile memory You can output the arbitrary waveform directly from volatile memory or you can copy the waveform to non volatile memory using the DATA COPY command 4 Select the arbitrary waveform to output You can select one of the five built in arbitrary waveforms one of four user defined waveforms or the waveform currently downloaded to volatile memory Use the FUNC USER command to select the waveform 5 Output the selected arbitrary waveform Use the FUNC US selected with the FUNC USER command The five built in a ER command to output the waveform previously rbitrary waveforms are shown below V eals
70. factory and the address is set to 10 The default settings for RS 232 are 57 6K bps 8 bits with no parity and DTR DSR handshake The programming examples in this chapter assume these default settings To change the GPIB address or to select the RS 232 interface instead DONE 277 Chapter 6 Application Programs Example BASIC for Windows Example BASIC for Windows 10 ik MENEREN AEE EE IE IEE IEI PETE TER R EE RU UR YE EE A PENE IE E PEPE UR VEVI VE VE VETE VE YE VE TEIE VE E E EEE 20 Copyright c 2000 Agilent Technologies All Rights Reserved l 30 l i 40 Agilent Technologies provides programming samples for illustration 50 purposes only This sample program assumes that you are familiar 60 with the programming language being demonstrated and the tools used 70 to create and debug procedures Agilent support engineers can help 80 answer questions relating to the functionality of the software 90 components provided by Agilent but they will not modify these samples 00 to provide added functionality or construct procedures to meet your 10 specific needs 20 You have a royalty free right to use modify reproduce and distribute 30 this sample program and or any modified version in any way you find 40 useful provided that you agree that Agilent has no warranty 50 obligations or liability for any sample programs 60 MAANA E E EIEII IETEN PEIEE EI ART EEIE IIE IE IE VE
71. following commands VOLTage HIGH lt voltage gt MINimum MAXimum VOLTage LOW lt voltage gt MINimum MAXimum You can also use the APPLy command to select the function frequency amplitude and offset with a single command 55 Chapter 3 Features and Functions Output Configuration Output Units Applies to output amplitude only At power on the units for output amplitude are volts peak to peak Output units Vpp Vrms or dBm The default is Vpp The unit setting is stored in volatile memory the units are set to Vpp when power has been off or after a remote interface reset The function generator uses the current units selection for both front panel and remote interface operations For example if you select VRMS from the remote interface the units are displayed as VRMS on the front panel The output units for amplitude cannot be set to dBm if the output termination is currently set to high impedance The units are automatically converted to Vpp Front Panel Operation Use the numeric keypad to enter the desired magnitude and then press the appropriate softkey to select the units You can also convert from one unit to another from the front panel For example to convert 2 Vpp to its equivalent value in Vrms and then press the Vamps softkey The converted value is 707 1 mVrms for a sine wave Remote Interface Operation VOLTage UNIT VPP VRMS DBM 56 Chapter 3
72. for which you must substitute a value e A vertical bar separates multiple parameter choices 48 Chapter 3 Features and Functions Output Configuration Output Configuration This section contains information to help you configure the function generator for outputting waveforms You may never have to change some of the parameters discussed here but they are provided to give you the flexibility you might need Output Function The function generator can output five standard waveforms including sine square ramp pulse and noise You can also select one of five built in arbitrary waveforms or create your own custom waveforms You can internally modulate any of the standard waveforms except pulse and noise and also arbitrary waveforms using AM FM or FSK Linear or logarithmic frequency sweeping is available for any of the standard waveforms except pulse and noise and also arbitrary waveforms You can generate a burst waveform using any of the standard waveforms and also arbitrary waveforms The default function is sine wave e The table below shows which output functions are allowed with modulation sweep and burst Each e indicates a valid combination If you change to a function that is not allowed with modulation sweep or burst then the modulation or mode is turned off Sine Square Ramp Pulse Noise DC Arb AM FM Carrier e e e FSK Carrier e e Sweep Mode
73. from which the function generator will accept a trigger e Sweep trigger source Internal External or Manual The default is Internal e The function generator will accept a manual trigger a hardware trigger from the rear panel Trig In connector or continuously output sweeps or bursts using an internal trigger At power on internal trigger is selected 98 Chapter 3 Features and Functions Triggering e The trigger source setting is stored in volatile memory the source is set to internal trigger front panel or immediate remote interface when power has been off or after a remote interface reset e Front Panel Operation After enabling sweeps or bursts press the Trigger Setup softkey Then select the desired source by pressing the Source softkey e Remote Interface Operation TRIGger SOURce IMMediate EXTernal BUS The APPLy command automatically sets the source to Immediate Internal Triggering In the internal trigger mode the function generator continuously outputs the sweep or burst as specified by the sweep time or burst period This is the power on trigger source for both front panel and remote interface use e Front Panel Operation Press the Trigger Setup softkey and then select the Source Int softkey e Remote Interface Operation TRIGger SOURce IMMediate Manual Triggering In the manual trigger mode front panel only you can manually trigger the function generator by pressing the front
74. internal modulating frequency in hertz AM DEPTh lt depth in percent gt MINimum MAXimum AM DEPTh MINimum MAXimum Set the internal modulation depth or percent modulation in percent Select from 0 to 120 The default is 100 MIN 0 MAX 120 The DEPT query returns the modulation depth in percent e Note that even at greater than 100 depth the function generator will not exceed 5V peak on the output into a 50Q load e Ifyou select the External modulating source AM SOUR EXT command the carrier waveform is modulated with an external waveform The modulation depth is controlled by the 5V signal level present on the rear panel Modulation In connector For example if you have set the modulation depth to 100 using the AM DEPT command then when the modulating signal is at 5 volts the output will be at the maximum amplitude When the modulating signal is at 5 volts then the output will be at the minimum amplitude AM STATe OFF ON AM STATe Disable or enable AM To avoid multiple waveform changes you can enable AM after you have set up the other modulation parameters The default is OFF The STAT query returns 0 OFF or 1 ON e The function generator will allow only one modulation mode to be enabled at a time For example you cannot enable AM and FM at the same time When you enable AM the previous modulation mode is turned off e The function generator will not allow
75. is the first waveform point downloaded to memory This command has no effect on pulse or noise waveforms e The burst phase is also used in the gated burst mode When the gate signal goes false the current waveform cycle is completed and then the function generator stops The output will remain at the voltage level corresponding to the starting burst phase 191 Chapter 4 Remote Interface Reference Burst Mode Commands BURSt STATe OFF ON BURSt STATe Disable or enable the burst mode To avoid multiple waveform changes you can enable the burst mode after you have set up the other burst parameters The default is OFF The STAT query returns 0 OFF or 1 ON e The function generator will not allow the burst mode to be enabled at the same time that sweep or any modulation mode is enabled When you enable burst the sweep or modulation mode is turned off UNIT ANGLe DEGree RADian UNIT ANGLe Select degrees or radians to set the starting phase for the burst with the BURS PHAS command remote interface only The default is DEG The ANGL query returns DEG or RAD e From the front panel the starting phase is always displayed in degrees radians are not available If you set the starting phase in radians from the remote interface and then return to front panel operation you will see that the function generator converts the phase to degrees TRIGger SOURce IMMediate EXTernal BUS TR
76. master s 10 MHz Out connector to the slave s 10 MHz In connector using a high quality coaxial cable This configuration will ensure that both instruments will generate exactly the same frequency and that there will not be any long term phase shift between the two instruments Next connect the two Trig In Out connectors together to allow the master to trigger the slave ee IN if U hig PA S L C LJ Slave After making the connections shown above follow the steps below to configure the two instruments 1 Configure both instruments to output a 5 MHz sine waveform 2 On both instruments enable the N Cycle burst mode set the burst count to three cycles and set the starting phase to 0 degrees 3 On the master select the Internal trigger source and enable the trigger out signal with a rising edge from the Trig Out connector 316 Chapter 7 Tutorial Burst 4 On the slave select the External trigger source and enable triggering on the rising edge of the trigger signal 5 Using an oscilloscope verify that both instruments are now generating a three cycle burst waveform Then adjust the trigger delay parameter of one instrument to bring the two bursts into alignment with each other The two instruments are now synchronized and will remain synchronized until you adjust the trigger delay parameters 6
77. modulation parameters Press cd and then select AM using the Type softkey The AM waveform is output using the present settings for the carrier frequency modulating frequency output amplitude and offset voltage e Remote Interface Operation To avoid multiple waveform changes enable AM after you have set up the other modulation parameters AM STATe OFF ON 67 Chapter 3 Features and Functions Amplitude Modulation AM Carrier Waveform Shape e AM carrier shape Sine Square Ramp or Arbitrary waveform The default is Sine You cannot use pulse noise or de as the carrier waveform e Front Fanel Operation Press any of the front panel function keys except Pulse Noise Ab and then choose the Select Wform softkey to select the active waveform e Remote Interface Operation FUNCtion SHAPe SINusoid SQUare RAMP USER You can also use the APPLy command to select the function frequency amplitude and offset with a single command Carrier Frequency The maximum carrier frequency depends on the function selected as shown below The default is 1 kHz for all functions Function Minimum Frequency Maximum Frequency Sine 1 wHz 80 MHz Square 1 wHz 80 MHz Ramp 1 wHz 1 MHz Arbs 1 wHz 25 MHz e Front Panel Operation To set the carrier frequency press the Freq softkey for the selected function Then use the knob or numeric keypad to enter the desired frequency e Remote Interfac
78. modulation parameters Press od and then select FM using the Type softkey The FM waveform is output using the present settings for the carrier frequency modulating frequency output amplitude and offset voltage e Remote Interface Operation To avoid multiple waveform changes enable FM after you have set up the other modulation parameters FM STATe OFF ON 72 Chapter 3 Features and Functions Frequency Modulation FM Carrier Waveform Shape FM carrier shape Sine Square Ramp or Arbitrary waveform The default is Sine You cannot use pulse noise or de as the carrier waveform Front Fanel Operation Press any of the front panel function keys e Noise Ai J and then choose e Select Wform softkey to select the active waveform Remote Interface Operation FUNCtion SHAPe SINusoid SQUare RAMP USER You can also use the APPLy command to select the function frequency amplitude and offset with a single command 73 Chapter 3 Features and Functions Frequency Modulation FM Carrier Frequency The maximum carrier frequency depends on the function selected as shown below The default is 1 kHz for all functions Function Minimum Frequency Maximum Frequency Sine 5 Hz 80 MHz Square 5 Hz 80 MHz Ramp 5 Hz 1 MHz Arbs 5 Hz 25 MHz e The carrier frequency must always be greater than or equal to the frequency deviation If you attempt to set the deviation to a value greate
79. most negative voltage level for the selected function and MAX selects the largest voltage level The HIGH and LOW queries return the high and low levels respectively e Limits Due to Amplitude You can set the voltage levels to a positive or negative value with the restrictions shown below Vpp is the maximum peak to peak amplitude for the selected output termination 10 Vpp for a 50 ohm load or 20 Vpp for a high impedance load Vhigh Vlow lt Vpp max and _ Vhigh Vlow lt ee If the specified level is not valid the function generator will automatically adjust it to the maximum voltage allowed From the remote interface a Data out of range error will be generated and the level will be adjusted as described e You can set the levels to a positive or negative value but note that the high level must always be greater than the low level If you specify a low level that is greater than the high level the function generator will automatically set the low level to be 1 mV less than the high level From the remote interface a Data out of range error will be generated and the level will be adjusted as described 159 Chapter 4 Remote Interface Reference Output Configuration Commands e Note that when you set the high and low levels you are also setting the amplitude of the waveform For example if you set the high level to 2 volts and the low level to 3 volts the resulting amplitude is 5 Vpp with an offset
80. noise APPL NOIS DEF 5 0 2 0 APPLy DC lt requency DEFault gt lt amplitude gt DEFault gt lt offset gt Output a de voltage with the level specified by the offset parameter You can set the de voltage to any value between 5 Vdc into 50 ohms or 10 Vdc into an open circuit The dc voltage is output as soon as the command is executed e The frequency and amplitude parameters have no effect for this command but you must specify a value or DEFault If you specify a frequency and amplitude they have no effect on the dc output but the values are remembered when you change to a different function The following statement shows the use of the APPLy command for a de output APPL DC DEF DEF 2 5 APPLy USER lt frequency gt lt amplitude gt lt offset gt Output the arbitrary waveform currently selected by the FUNC USER command The waveform is output using the specified frequency amplitude and dc offset The waveform is output as soon as the command is executed See page 198 for more information on downloading arbitrary waveforms to memory 151 Chapter 4 Remote Interface Reference Using the APPLy Command APPLy Query the function generator s current configuration and return a quoted string The purpose of this command is to allow you to append this query response to an APPL command in your programming application and use the result to place the function generator in the specified
81. on the level of the external signal applied to the rear panel Trig In connector The default is TRIG The MODE query returns TRIG or GAT e When the gated mode is selected the waveform generator either runs or stops based on the logic level of the gate signal applied to the rear panel Trig In connector You can select the polarity of the Trig In connector using the BURS GATE POL command see page 194 When the gate signal is true the function generator outputs a continuous waveform When the gate signal goes false the current waveform cycle is completed and then the function generator stops while remaining at the voltage level corresponding to the starting burst phase of the selected waveform For a noise waveform the output stops immediately when the gate signal goes false e When the gated mode is selected the burst count burst period and trigger source are ignored these parameters are used for the triggered burst mode only If a manual trigger is received TRIG command it is ignored and no error will be generated 189 Chapter 4 Remote Interface Reference Burst Mode Commands BURSt NCYCles lt cycles gt INFinity MINimum MAXimum BURSt NCYCles MINimum MAXimum Set the number of cycles to be output per burst triggered burst mode only Select from 1 cycle to 1 000 000 cycles in 1 cycle increments see the restrictions below The default is 1 cycle MIN 1 cycle MAX based on the
82. out FIFO order The first error returned is the first error that was stored Errors are cleared as you read them The function generator beeps once each time an error is generated unless you have disabled the beeper If more than 20 errors have occurred the last error stored in the queue the most recent error is replaced with Queue overflow No additional errors are stored until you remove errors from the queue If no errors have occurred when you read the error queue the function generator responds with No error The error queue is cleared by the CLS clear status command or when the power is cycled The errors are also cleared when you read the error queue The error queue is not cleared by an instrument reset RST command Front Panel Operation Press P and then select the topic entitled View the remote command error queue topic number 2 Then press the SELECT softkey to view the errors in the error queue As shown below the first error in the list i e the error at the top of the list is the first error that was generated Remote Inter mand Errors DONE Remote Interface Operation SYSTem ERRor Reads one error from the error queue Errors have the following format the error string may contain up to 255 characters 113 Undefined header 112 Chapter 3 Features and Functions System Related Operations Beeper Control Normally the function generator will emit a tone
83. press CONTinue 840 850 OUTPUT Fgen output state off Disable Output BNC 860 OUTPUT Fgen volt low 0 volt high 0 75 Low OV High 0 75V 870 OUTPUT Fgen pulse period le 3 Ims intervals 880 OUTPUT Fgen pulse width 100e 6 100us pulse width 890 OUTPUT Fgen pulse tran 10e 6 Edge time 10us 900 OUTPUT Fgen func pulse Select Function Pulse 910 OUTPUT Fgen output state on Enable Output BNC 920 FOR I 1 TO 10 Vary edge by lusec steps 930 OUTPUT Fgen puls tran 1 0E 5 1I 1 E 6 940 WAIT 3 950 NEXT 960 Check_errors Routine checks for errors 970 PAUSE 980 Continued 279 Chapter 6 Application Programs Example BASIC for Windows Turn OFF Output BNC Burst of 3 cycles per trigger Routine checks for errors using ASCII press CONTinue Valid range 1 0 to 1 0 Read constants into array Download 20 point waveform Select downloaded waveform Output waveform 10kHz l1Vpp Routine checks for errors Valid range 2047 to 2047 Read constants into array Send command suppress CR LF Time to switch to binary mode 12 bytes no terminator Time to switch to ASCII mode Routine checks for errors 990 PRINT Triggered Burst press CONTinue 000 010 OUTPUT Fgen output state off 020 OUTPUT Fgen output sync off Disable Sync BNC 030 OUTPUT Fgen func square Select square wave 040 OUTPUT Fgen frequency 2063 20kHz 050 OUTPUT Fg
84. rate at which the function generator can execute commands from the remote interface you may want to turn off the front panel display From the remote interface you can also display a 12 character message on the front panel You can only disable the front panel display by sending a command from the remote interface you cannot disable the front panel while in local operation When disabled the front panel display is blanked however the bulb used to backlight the display remains enabled All keys except L are locked out when the display is disabled Sending a message to the front panel display from the remote interface overrides the display state This means that you can display a message even if the display is currently disabled remote interface errors are always displayed even if the display is disabled The display is automatically enabled when power is cycled after an instrument reset RST command or when you return to local front panel operation Press the key or execute the IEEE 488 GTL Go To Local command from the remote interface to return to the local state The display state is saved when you store the instrument state using SAV command When you recall the instrument state using RCL command the front panel display will return to the previous state You can display a text message on the front panel by sending a command from the remote interface You can use upper or lower case letters A Z numbers 0 9
85. refer to the reference manual that came with your programming application for further details on instrument control Using the APPLy Command The APPLy command provides the most straightforward method to program the function generator over the remote interface For example the following command string sent from your computer will output a 3 Vpp sine wave at 5 kHz with a 2 5 volt offset APPL SIN 5 0E 3 3 0 2 5 Using the Low Level Commands Although the APPLy command provides the most straightforward method to program the function generator the low level commands give you more flexibility to change individual parameters For example the following command strings sent from your computer will output a 3 Vpp sine wave at 5 kHz with a 2 5 volt offset FUNC SIN Select sine wave function FREQ 5000 Set frequency to 5 kHz VOLT 3 0 Set amplitude to 3 Vpp VOLT OFFS 2 5 Set offset to 2 5 Vdc 142 Chapter 4 Remote Interface Reference Simplified Programming Overview Reading a Query Response Only the query commands commands that end with will instruct the function generator to send a response message Queries return internal instrument settings For example the following command string sent from your computer will read the function generator s error queue and retrieve the response from the most recent error dimension statement Dimension string array 255 elements SYST ERR Read error queue enter stat
86. return to the ramp wave function the previous symmetry is used e Ifyou select a ramp waveform as the modulating waveform for AM or FM the symmetry setting does not apply OUTPut OFF ON OUTPut Disable or enable the front panel Output connector The default is OFF When the output is enabled the key is illuminated on the function generator s front panel The OUTP query returns 0 OFF or 1 ON e The APPLy command overrides the current OUTP command setting and automatically enables the Output connector ON e If an excessive external voltage is applied to the front panel Output connector an error message will be displayed and the output will be disabled To re enable the output remove the overload from the Output connector and send the OUTP ON command 162 Chapter 4 Remote Interface Reference Output Configuration Commands OUTPut LOAD lt ohms gt INFinity MINimum MAXimum OUTPut LOAD MINimum MAXimum Select the desired output termination i e the impedance of the load attached to the output of the Agilent 33250A The specified value is used for amplitude offset and high low level settings You can set the load to any value from 19 to 10 KQ MIN selects 10 MAX selects 10 KQ INF sets the output termination to high impedance gt 10 kQ The default is 50Q The LOAD query returns the current load setting in ohms or 9 9E 37 for high impedance e The Agi
87. set the value to 500 Hz using the numeric keypad or the knob and arrow keys FSK l 50 208 000 000_ Hz WW EEH 4 Set the FSK shift rate Press the FSK Rate softkey and then set the value to 100 Hz using the numeric keypad or the knob and arrow keys At this point the function generator outputs an FSK waveform if the output is enabled 5 View the waveform 37 Chapter 2 Front Panel Menu Operation To Output a Frequency Sweep To Output a Frequency Sweep In the frequency sweep mode the function generator steps from the start frequency to the stop frequency at a sweep rate which you specify You can sweep up or down in frequency and with either linear or logarithmic spacing For this example you will output a swept sine wave from 50 Hz to 5 kHz You will not change the other parameters from their default settings internal sweep trigger linear spacing and 1 second sweep time terebiepeperehergerdeepeabp ged pbede pe i qi IS 1 I i PE Jee dees BE J H d N Select the function and amplitude for the sweep For sweeps you can select sine square ramp or arbitrary waveforms pulse noise and dc are not allowed For this example select a sine wave with an amplitude of 5 Vpp Select the sweep mode Press 6 5 and then verify that the linear sweep mode is currently selected Notice that a status message Linear Sweep is shown in the upper left corner of
88. state for each of the calibration steps to be performed The VAL query returns a number in the form 1 0000000000000E 01 CALibration Perform a calibration of the instrument using the specified calibration value CAL VAL command Before you can calibrate the function generator you must unsecure it by entering the correct security code Returns 0 PASS or 1 FAIL 239 Chapter 4 Remote Interface Reference Calibration Commands CALibration SECure CODE lt new code gt Enter a new security code To change the security code you must first unsecure the function generator using the old security code and then enter a new code The security code is stored in non volatile memory e The calibration code may contain up to 12 characters The first character must be a letter A Z but the remaining characters can be letters numbers 0 9 or the underscore character _ You do not have to use all 12 characters but the first character must always be a letter CALibration COUNt Query the instrument to determine the number of times it has been calibrated Note that your instrument was calibrated before it left the factory When you receive your instrument from the factory be sure to read the count to determine its initial value e The calibration count is stored in non volatile memory The count increments up to a maximum of 65 535 after which it rolls over to 0 Since the value incre
89. storage ARB_1 DATA COPY ARB_1 VOLATILE FUNCtion USER lt arb name gt VOLATILE FUNCtion USER Select one of the five built in arbitrary waveforms one of four user defined waveforms or the waveform currently downloaded to volatile memory The USER query returns EXP_RISE EXP_FALL NEG_RAMP SINC CARDIAC VOLATILE or the name of any user defined waveforms in non volatile memory e Note that this command does not output the selected arbitrary waveform Use the FUNC USER command see the following page to output the selected waveform e The names of the five built in arbitrary waveforms are EXP_RISE EXP_FALL NEG_RAMP SINC and CARDIAC e To select the waveform currently stored in volatile memory specify the VOLATILE parameter The keyword VOLATILE does not have a short form e Ifyou select a waveform name that is not currently downloaded a Specified arb waveform does not exist error is generated 204 Chapter 4 Remote Interface Reference Arbitrary Waveform Commands The function generator does not distinguish between upper and lower case letters Therefore ARB_1 and arb_1 are the same name All characters are converted to upper case Use the DATA CAT command to list the names of the five built in waveforms non volatile VOLATILE if a waveform is currently downloaded to volatile memory and the names of
90. the arbitrary waveform that is currently being output If you attempt to delete this waveform a Not able to delete the currently selected active arb waveform error is generated You cannot delete any of the five built in arbitrary waveforms If you attempt to delete one of these waveforms a Not able to delete a built in arb waveform error is generated Use the DATA DEL ALL command to delete the waveform in volatile memory and all user defined non volatile waveforms all at once If one of the waveforms is currently being output a Not able to delete the currently selected active arb waveform error is generated DATA DELete ALL Delete all user defined arbitrary waveforms from memory This command deletes the waveform in volatile memory and all user defined waveforms in non volatile memory The five built in waveforms in non volatile memory are not deleted The colon before the ALL parameter is required DATA DELete ALL If you insert a space instead of a colon the function generator will attempt to delete an arbitrary waveform with the name ALL If no such waveform is stored in memory a Specified arb waveform does not exist error is generated Use the DATA DEL lt arb name gt command to delete stored waveforms one at a time You cannot delete the arbitrary waveform that is currently being output If you attempt to delete this waveform a Not able to delete the currently selected active a
91. the carrier waveform FSKey SOURce INTernal EXTernal FSKey SOURce Select an internal or external FSK source The default is INT The SOUR query returns INT or EXT e When the Internal source is selected the rate at which the output frequency shifts between the carrier frequency and hop frequency is determined by the FSK rate specified FSK INT RATE command e When the External source is selected the output frequency is determined by the signal level on the rear panel Trig In connector When a logic low level is present the carrier frequency is output When a logic high level is present the hop frequency is output e The maximum external FSK rate is 1 MHz e Note that the connector used for externally controlled FSK waveforms Trig In is not the same connector that is used for externally modulated AM and FM waveforms Modulation In When used for FSK the Trig In connector does not have adjustable edge polarity and is not affected by the TRIG SLOP command 177 Chapter 4 Remote Interface Reference Frequency Shift Keying FSK Commands FSKey FREQuency lt frequency gt MINimum MAXimum FSKey FREQuency MINimum MAXimum Set the FSK alternate or hop frequency Select from 1 uHz to 80 MHz limited to 1 MHz for ramps and 25 MHz for arbitrary waveforms The default is 100 Hz MIN 1 Hz MAX 80 MHz The FREQ query returns the hop frequency in hertz e Th
92. the function generator outputs continuously when the sweep mode or burst mode is enabled When the External source is selected the function generator will accept a hardware trigger applied to the rear panel Trig In connector The function generator initiates one sweep or outputs one burst each time Trig In receives a TTL pulse with the edge polarity specified by the TRIG SLOP command see page 196 When the Bus software source is selected the function generator initiates one sweep or outputs one burst each time a bus trigger command is received To trigger the function generator from the remote interface GPIB or RS 232 when the Bus source selected send the TRIG or TRG trigger command The front panel key is illuminated when the function generator is waiting for a bus trigger The APPLy command automatically sets the trigger source to Immediate equivalent to TRIG SOUR IMM command 195 Chapter 4 Remote Interface Reference Triggering Commands e To ensure synchronization when the Bus source is selected send the WAL wait command When the WAI command is executed the function generator waits for all pending operations to complete before executing any additional commands For example the following command string guarantees that the first trigger is accepted and the operation is executed before the second trigger is recognized TRIG SOUR BUS TRG WAI TRG WAI e You can use the OPC operation complete qu
93. the sweep or burst e When the Bus software trigger source is selected TRIG SOUR BUS command the function generator outputs a pulse gt 1 ps pulse width from the Trig Out connector at the beginning of each sweep or burst OUTPut TRIGger OFF ON OUTPut TRIGger Disable or enable the trigger out signal used for sweep and burst only When enabled a TTL compatible square waveform with the specified edge OUTP TRIG SLOP command is output from the rear panel Trig Out connector at the beginning of the sweep or burst The default is OFF The TRIG query returns 0 OFF or 1 ON 197 Chapter 4 Remote Interface Reference Arbitrary Waveform Commands Arbitrary Waveform Commands See also Arbitrary Waveforms starting on page 103 in chapter 3 Arbitrary Waveform Overview The following is an overview of the steps required to download and output an arbitrary waveform over the remote interface The commands used for arbitrary waveforms are listed on page 200 Refer to chapter 7 Tutorial for more information on the internal operation of downloading and outputting an arbitrary waveform Chapter 6 Application Programs contains example programs which show the use of arbitrary waveforms You may find it useful to refer to the programs after reading the following section in this chapter Select the waveform frequency amplitude and offset Use the APPLy command or the
94. to equipment or permanent loss of data Earth ground symbol Chassis ground symbol WARNING Only qualified service trained personnel who are aware of the hazards involved should remove the cover from the instrument Agilent Technologies Inc P O Box 301 815 14th Street S W Loveland Colorado 80539 0301 U S A
95. value between 5 Vdc into 50 ohms or 10 Vdc into an open circuit 157 Chapter 4 Remote Interface Reference Output Configuration Commands VOLTage OFFSet lt offset gt MINimum MAXimum VOLTage OFFSet MINimum MAXimum Set the dc offset voltage The default offset is 0 volts for all functions MIN selects the most negative dc offset voltage for the selected function and amplitude MAX selects the largest dc offset for the selected function and amplitude The OFFS query returns the offset voltage for the function currently selected e Limits Due to Amplitude The relationship between offset voltage and output amplitude is shown below Vmax is the maximum peak voltage for the selected output termination 5 volts for a 50Q load or 10 volts for a high impedance load Voffset lt Vmax Yep If the specified offset voltage is not valid the function generator will automatically adjust it to the maximum dc voltage allowed with the amplitude specified From the remote interface a Data out of range error will be generated and the offset will be adjusted as described e Limits Due to Output Termination The offset limits are determined by the current output termination setting For example if you set the offset to 100 mVdc and then change the output termination from 50 ohms to high impedance the offset voltage displayed on the function generator s front panel will double to 200 mVdc and no error will be gener
96. voltage of 500 mV e Limits Due to Output Termination If you change the output termination setting the displayed voltage levels will be automatically adjusted and no error will be generated For example if you set the high level to 100 mVdc and then change the output termination from 50 ohms to high impedance the voltage displayed on the function generator s front panel will double to 200 mVdc If you change from high impedance to 50 ohms the displayed voltage will drop in half See the OUTP LOAD command on page 163 for more information e To invert the waveform relative to the offset voltage you can use the OUTP POL command See page 164 for more information VOLTage RANGe AUTO OFF ON ONCE VOLTage RANGe AUTO Disable or enable voltage autoranging for all functions In the default mode autoranging is enabled ON and the function generator automatically selects the optimal settings for the output amplifier and attenuators With autoranging disabled OFF the function generator uses the current amplifier and attenuator settings The AUTO query returns 0 OFF or 1 ON e The APPLy command overrides the voltage autorange setting and automatically enables autoranging ON e The advantage of disabling autoranging is to eliminate momentary disruptions caused by switching of the attenuators while changing amplitude However the amplitude and offset accuracy and reso
97. you cannot use noise pulse or de as the carrier waveform If you select an arbitrary waveform as the modulating waveshape the waveform is automatically limited to 8K points Extra waveform points are removed using decimation Front Panel Operation After enabling FM press the Shape softkey Remote Interface Operation FM INTernal FUNCtion SINusoid SQUare RAMP NRAMp TRIlangle NOISe USER Modulating Waveform Frequency The function generator will accept an internal or external modulation source for FM Modulating frequency internal source 2 mHz to 20 kHz The default is 10 Hz Front Panel Operation After enabling FM press the FM Freq softkey Remote Interface Operation FM INTernal FREQuency lt frequency gt MINimum MAXimum 75 Chapter 3 Features and Functions Frequency Modulation FM Peak Frequency Deviation The peak frequency deviation represents the variation in frequency of the modulating waveform from the carrier frequency Peak frequency deviation 5 Hz to 40 05 MHz limited to 550 kHz for ramps and 12 55 MHz for arbitrary waveforms The default is 100 Hz The carrier frequency must always be greater than or equal to the deviation If you attempt to set the deviation to a value greater than the carrier frequency with FM enabled the function generator will limit the deviation to the maximum value allowed with the present carrier frequency The sum of the carrier frequen
98. you will output a three cycle sine wave with a 20 ms burst period You will not change the other parameters from their default settings internal burst source and 0 degree starting phase Select the function and amplitude for the burst For burst waveforms you can select sine square ramp pulse or arbitrary waveforms noise is allowed only in the gated burst mode and dc is not allowed For this example select a sine wave with an amplitude of 5 Vpp Select the burst mode urt and then verify that the N Cycle internally triggered mode is currently selected Notice that a status message N Cycle Burst is shown in the upper left corner of the display 40 Chapter 2 Front Panel Menu Operation To Output a Burst Waveform 3 Set the burst count Press the Cycles softkey and then set the count to 3 using the numeric keypad or knob Int Trigger Cyc Wh a x p 12 N N Cyclall Cyclesd E a a T Trigger Gated Infinite Phase Period Delay Setup 4 Set the burst period Press the Burst Period softkey and then set the period to 20 ms using the numeric keypad or the knob and arrow keys The burst period sets the time from the start of one burst to the start of the next burst note the display icon Burst Int Trigger i 20 os G ated tr finite P At this point the function generator outputs a continuous three cycle burst if the output is enabled 5 View the wa
99. 0 volts for a high impedance load If the specified offset voltage is not valid the function generator will automatically adjust it to the maximum dc voltage allowed with the amplitude specified Voffset lt Vmax Yep Settings conflict amplitude changed due to offset The relationship between output amplitude and offset voltage is shown below Vmax is the maximum peak voltage for the selected output termination 5 volts for a 50Q load or 10 volts for a high impedance load If the specified amplitude not valid the function generator will automatically adjust it to the maximum value allowed with the offset voltage specified Vpp lt 2 X Vmax Voffset Settings conflict low level changed due to high level You can set the levels to a positive or negative value but note that the high level must always be greater than the low level If you specify a high level that is less than the low level the function generator will automatically set the low level to be 1 mV less than the high level Settings conflict high level changed due to low level You can set the levels to a positive or negative value but note that the high level must always be greater than the low level If you specify a low level that is greater than the high level the function generator will automatically set the high level to be 1 mV greater than the low level 260 222 222 222 222 222 Chapter 5 Error Messages Execution Errors
100. 000 is the same as sending the following two commands FREQ START 10 FREQ STOP 1000 Use a colon and a semicolon to link commands from different subsystems For example in the following command string an error is generated if you do not use both the colon and semicolon SWE STAT ON TRIG SOUR EXT Using the MIN and MAX Parameters You can substitute MINimum or MAXimum in place of a parameter for many commands For example consider the following command FREQuency lt frequency gt MINimum MAXimum Instead of selecting a specific frequency you can substitute MIN to set the frequency to its minimum value or MAX to set the frequency to its maximum value 243 Chapter 4 Remote Interface Reference An Introduction to the SCPI Language Querying Parameter Settings You can query the current value of most parameters by adding a question mark to the command For example the following command sets the output frequency to 5 kHz FREQ 5000 You can then query the frequency value by executing FREQ You can also query the minimum or maximum frequency allowed with the present function as follows FREQ MIN FREQ MAX SCPI Command Terminators A command string sent to the function generator must terminate with a lt new line gt character The IEEE 488 EOI End Or Identify message is interpreted as a lt new line gt character and can be used to ter
101. 1 Cross isolation UART framing error 502 Cross isolation UART overrun error 503 Cross isolation UART parity error 504 Cross isolation UART noise error These errors indicate either an internal hardware failure or a defect in the firmware controlling interactions with the GPIB and RS 232 logic circuits The isolation between chassis ground circuits and floating circuits is controlled by an optical isolation barrier and a serial link Not able to execute command while GPIB selected The SYST LOCAL and SYST RWLOCK commands are valid only when the RS 232 interface is selected T O processor output buffer overflow This error indicates either an internal hardware failure or a defect in the firmware controlling interactions with the GPIB and RS 232 logic circuits T O processor received unknown code This error indicates either an internal hardware failure or a defect in the firmware controlling interactions with the GPIB and RS 232 logic circuits Reference phase locked loop is unlocked The PHAS UNL ERR STAT has been enabled on and the internal phase locked loop that controls the frequency is currently unlocked This error is most likely to occur when the external reference is out of lock range T O processor had unexpected reset This error indicates either an internal hardware failure or a defect in the firmware controlling interactions with the GPIB and RS 232 logic circuits 268 Chapter 5 Error Messages Self Test E
102. 1 ps MAX based on the burst count and waveform frequency as shown below The PER query returns the burst period in seconds e The burst period setting is used only when Immediate triggering is enabled TRIG SOUR IMM command The burst period is ignored when manual or external triggering is enabled or when the gated burst mode is selected e Itis not possible to specify a burst period which is too short for the function generator to output with the specified burst count and frequency see below If the burst period is too short the function generator will automatically adjust it as needed to continuously re trigger the burst From the remote interface a Data out of range error will be generated and the burst period will be adjusted as described Burst Count x 200 ns Waveform Frequency Burst Period gt BURSt PHASe lt angle gt MINimum MAXimum BURSt PHASe MINimum MAXimum Set the starting phase for the burst in degrees or radians as specified by the previous UNIT ANGL command Select from 360 degrees to 360 degrees or 2r to 27 radians The default is 0 degrees 0 radians MIN 360 degrees 27 radians MAX 360 degrees 27 The PHAS query returns the starting phase in degrees or radians e For sine square and ramp waveforms 0 degrees is the point at which the waveform crosses zero volts or the dc offset value in a positive going direction For arbitrary waveforms 0 degrees
103. 10th of output amplitude and offset specification per C for operation outside of 0 C to 28 C range 1 year specification wo a Sine and square waveforms above 25 MHz are allowed only with an Infinite burst count 20 mVpp to 20 Vpp into open circuit load dB rounded to 1 digit Instrument adheres to specification Short circuit protected to ground at all times 321 Chapter 8 Specifications Agilent 33250A Function Arbitrary Waveform Generator SYSTEM CHARACTERISTICS Configuration Times typical Function Change Standard 2 Pulse Built In Arb 2 Frequency Change Amplitude Change Offset Change Select User Arb Modulation Change 102 ms 660 ms 240 ms 24 ms 50 ms 50 ms lt 400 ms for lt 16K points lt 200 ms Arb Download Times GPIB RS 232 115 Kbps Arb Length Binary ASCII Integer ASCII Real 64K points 23 sec 92 sec 154 sec 16K points 6 sec 23 sec 39 sec 8K points 3 sec 12 sec 20 sec 4K points 1 5 sec 6 sec 10 sec 2K points 0 75 sec 3 sec 5 sec TRIGGER CHARACTERISTICS Trigger Input Input Level Slope Pulse Width Input Impedance Latency Sweep Burst Jitter rms Sweep Burst Trigger Output Level Pulse Width Maximum Rate Fanout TTL compatible Rising or falling selectable gt 100 ns 10 kQ DC coupled lt 10 us typical lt 100 ns typical 2 5 us ns except pulse 300 ps TTL co
104. 211 Chapter 4 Remote Interface Reference State Storage Commands MEMory STATe RECal1l AUTO OFF ON MEMory STATe RECal1 AUTO Disable or enable the automatic recall of the power down state from storage location 0 when power is turned on Select ON to automatically recall the power down state when power is turned on Select OFF default to issue a reset RST command when power is turned on state O is not automatically recalled The AUTO query returns 0 OFF or 1 ON MEMory STATe VALid 0 1 2 3 4 Query the specified storage location to determine if a valid state is currently stored in that location You can use this command before sending the RCL command to determine if a state has been previously stored in this location Returns 0 if no state has been stored or if it has been deleted Returns 1 if a valid state is stored in the specified location MEMory NSTates Query the total number of memory locations available for state storage Always returns 5 memory location 0 is included 212 Chapter 4 Remote Interface Reference System Related Commands System Related Commands See also System Related Operations starting on page 109 in chapter 3 SYSTem ERRor Read and clear one error from the function generator s error queue A record of up to 20 command syntax or hardware errors can be stored in the error queue See chapter 5 for a
105. 22 Chapter 4 Remote Interface Reference Phase Lock Commands Phase Lock Commands The rear panel 10 MHz In and 10 MHz Out connectors allow synchronization between multiple Agilent 33250As see connection diagram below or to an external 10 MHz clock signal You can also control the phase offset from the front panel or over the remote interface a Moan Tainan h FSK Bursi Ar PHASe lt angle gt MINimum MAXimum PHASe MINimum MAXimum Adjust the phase offset of the output waveform in degrees or radians as specified by the previous UNIT ANGL command not available for pulse and noise Select from 360 degrees to 360 degrees or 27 to 27 radians The default is 0 degrees 0 radians MIN 360 degrees 27 radians MAX 360 degrees 27 radians The PHAS query returns the phase offset in degrees or radians e The specified phase adjustment causes a bump or hop in the output waveform in order to change the phase relationship to the external signal to which it is currently locked e This phase adjustment for phase lock applications is independent of the burst phase as set by the BURS PHAS command see page 191 223 Chapter 4 Remote Interface Reference Phase Lock Commands UNIT ANGLe DEGree RADian UNIT ANGLe Select degrees or radians to set the phase offset value using the
106. 50us div 200mV div Channel 2 Sync BNC 50us div 500mV div trigger on Channel 2 Microsoft Visual C 6 0 for GPIB RS 232 3 30 00 fp include lt stdio h gt include lt comdef h gt Import the IO0Utils your directory is dependent on where BenchLlink XL was installed pragma warning disable 4192 Suppresses warning from import import C siclnt servers AgtIOUtils dll using namespace AgilentIOUtilsLib Continued 287 Chapter 6 Application Programs Example Microsoft Visual C for Windows void Check_Errors IIO pIOObj _variant_t ErrNum ErrStr while 1 ErrNum Initialize variants Errstr ploOObj gt Output SYST ERR pl0OObj gt Enter amp ErrNum K Read number don t flush input buffer ploOObj gt Enter amp ErrStr K Read the string ErrNum ChangeType VT_I4 if long ErrNum 0 Checking for 0 No Error break else printf nERROR d SS n long ErrNum ErrStr bstrVal void Pause Routine to permit stopping of execution of program printf Press Enter to continue fflush stdout fgetc stdin Wait for LF printf n void Fill_array double data 20 Routine can be used to fill array passed from Main Program Fills entire array with sequence of 1 0 ata ata ata ata ata ata ata ata ata ata ata ata ata ata ata ata ata ata
107. 81 Chapter 4 Remote Interface Reference Frequency Sweep Commands FREQuency CENTer lt frequency gt MINimum MAXimum FREQuency CENTer MINimum MAXimum Set the center frequency used in conjunction with the frequency span Select from 1 uHz to 80 MHz limited to 1 MHz for ramps and 25 MHz for arbitrary waveforms The default is 550 Hz MIN 1 uHz MAX based on the frequency span and maximum frequency for the selected function as shown below The CENT query returns the center frequency in hertz Center Frequency max Max Frequency Span e The following equation shows the relationship between the center frequency and the start stop frequency Genter Frequency Stop Frequency gt Start Frequency FREQuency SPAN lt frequency gt MINimum MAXimum FREQuency SPAN MINimum MAXimum Set the frequency span used in conjunction with the center frequency Select from 0 Hz to 80 MHz limited to 1 MHz for ramps and 25 MHz for arbitrary waveforms The default is 900 Hz MIN 0 Hz MAX based on the center frequency and maximum frequency for the selected function The SPAN query returns the span in hertz can be a positive or negative value Frequency Span max 2 X Max Frequency Center Frequency e To sweep up in frequency set a positive frequency span To sweep down in frequency set a negative frequency span e The following equation shows the relationship between the span and the start s
108. A lie Time 4 Set the edge time for both edges Press the Edge Time softkey and then set the edge time for both the rising and falling edges to 50 ps The edge time represents the time from the 10 threshold to the 90 threshold of each edge note the display icon W 0us AL Frec Ampl Pulse Edge Period MIESE ame ST RE E 22 Chapter 1 Quick Start To View a Waveform Graph To View a Waveform Graph In the Graph Mode you can view a graphical representation of the current waveform parameters Each softkey parameter is shown in a different color corresponding to the lines above the softkeys at the bottom of the display Note that the softkeys are listed in the same order as in the normal display mode Enable the Graph Mode Press the key to enable the Graph Mode The name of the parameter currently selected is shown in the upper left corner of the display and the numeric value is highlighted Frequency Select the desired parameter To select a specific parameter note the colored bars above the softkeys at the bottom of the display and select the corresponding color For example to select amplitude press the softkey below the magenta colored bar e Asin the normal display mode you can edit numbers using either the numeric keypad or the knob and arrow keys e Parameters which normally toggle when you press a key a second time e g Freq Period also toggle in the Graph Mode e To exit th
109. AgtUtilsoO Copyright c 2000 Agilent Tec Agilent Technologies provides purposes only with the programming language to create and debug procedures answer questions relating to t Used to sequence messages bject hnologies All Rights Reserved being demonstrated and the tools Agilent support engineers can he functionality of the software WOVE Ue Te Tee Vee Oe TY We vee Oye OY We ve Oye Oy ne ny von eee en programming samples for illustration This sample program assumes that you are familiar used help components provided by Agilent but they will not modify these to provide added functionality or construct procedures to meet specificneeds You have a royalty free right to use modify reproduce this sample program and or any modified version in any way you find useful provided that you agree that Agilent has no warranty obligations or liability for any sample programs your r r y r L i r samples A r L and distribute d r r L Agilent 33250A 80 MHz Function Arbitrary Waveform Generator Examples Examples include Modulation Pulse Sweeping Burst and Status checking Examples illustrate various uses of short long form SCPI Examples also illustrate enabling disabling output BNCs To view results on Scope set to Channel 1 Output BNC 50ohms 50us div 200mV div Channel 2 Sync BNC 50us div 500mV div trigger on Channel 2 Microsoft Visual Basic 6 0 Programming Example
110. Chapter 3 Features and Functions Frequency Shift Keying FSK Modulation Carrier Waveform Shape e FSK carrier shape Sine Square Ramp or Arbitrary waveform The default is Sine You cannot use pulse noise or de as the carrier waveform e Front Fanel Operation Press any of the front panel function keys e Noise Ai J and then choose e Select Wform softkey to select the active waveform e Remote Interface Operation FUNCtion SHAPe SINusoid SQUare RAMP USER You can also use the APPLy command to select the function frequency amplitude and offset with a single command FSK Carrier Frequency The maximum carrier frequency depends on the function selected as shown below The default is 1 kHz for all functions Function Minimum Frequency Maximum Frequency Sine 1 wHz 80 MHz Square 1 wHz 80 MHz Ramp 1 wHz 1 MHz Arbs 1 wHz 25 MHz e When the External source is selected the output frequency is determined by the signal level on the rear panel Trig In connector When a logic low level is present the carrier frequency is output When a logic high level is present the hop frequency is output e Front Panel Operation To set the carrier frequency press the Freq softkey for the selected function Then use the knob or numeric keypad to enter the desired frequency e Remote Interface Operation FREQuency lt frequency gt MINimum MAXimum You can also use the APPLy command to select the functio
111. EE DATA DELete lt arb name gt DATA DELete ALL DATA ATTRibute AVERage lt arb name gt ATTRibute CFACtor lt arb name gt A A Ribute POINts lt arb name gt Ribute PTPeak lt arb name gt 1 The names of the built in arb waveforms are EXP_RISE EXP_FALL NEG_RAMP SINC and CARDIAC Parameters shown in bold are selected following a RST reset command 137 Chapter 4 Remote Interface Reference SCPI Command Summary Triggering Commands see page 195 for more information These commands are used for Sweep and Burst only TRIGger SOURce IMMediate EXTernal BUS TRIGger SOURce TRIGger TRG TRIGger DELay lt seconds gt MINimum MAXimum Triggered Burst Mode TRIGger DELay MINimum MAXimum TRIGger SLOPe POSitive NEGative Trig In Connector TRIGger SLOPe BURSt GATE POLarity NORMal INVerted External Gated Burst BURSt GATE POLarity OUTPut TRIGger SLOPe POSitive NEGative Trig Out Connector TRIGger SLOPe TRIGger OFF ON TRIGger State Storage Commands see page 209 for more information SAV 011121314 State 0 is the instrument state at power down RCL 011121314 States 1 through 4 are user defined states MEMory STATe NAME 0 1 2 3 4 lt name gt NAME 0 1 2 3 4 DELete 0 1 2 3 4 RECall AUTO OFF ON RECall AUTO STATe VALid 0 1 2 3 4 MEMor
112. Exponential Rise Exponential Fall Negative Ramp oe Ae Sinc Cardiac 199 Chapter 4 Remote Interface Reference Arbitrary Waveform Commands Arbitrary Waveform Commands DATA VOLATILE lt value gt lt value gt Download floating point values from 1 to 1 into volatile memory You can download from 1 to 65 536 64K points per waveform The function generator takes the specified number of points and expands them to fill waveform memory If you download less than 16 384 16K points a waveform with 16 384 points is automatically generated If you download more than 16 384 points a 65 536 point waveform is generated e The values 1 and 1 correspond to the peak values of the waveform if the offset is 0 volts For example if you set the amplitude to 10 Vpp OV offset 1 corresponds to 5V and 1 corresponds to 5V e The maximum amplitude will be limited if the data points do not span the full range of the output DAC Digital to Analog Converter For example the built in Sinc waveform does not use the full range of values between 1 and therefore its maximum amplitude is 6 087 Vpp into 50 ohms e Downloading floating point values using DATA VOLATILE is slower than downloading binary values using DATA DAC VOLATILE but is more convenient when using trigonometric functions which return values from 1 to 1 e The DATA command overwrites the previous wav
113. Features and Functions Output Configuration Output Termination Applies to output amplitude and offset voltage only The Agilent 33250A has a fixed series output impedance of 50 ohms to the front panel Output connector If the actual load impedance is different than the value specified the displayed amplitude and offset levels will be incorrect e Output termination 10 to 10 KQ or Infinite The default is 50Q e The output termination setting is stored in non volatile memory and does not change when power has been off or after a remote interface reset When shipped from the factory 50Q is selected e Ifyou specify a 50 ohm termination but are actually terminating into an open circuit the actual output will be twice the value specified For example if you set the offset to 100 mVdc and specify a 50 ohm load but are terminating the output into an open circuit the actual offset will be 200 mVdc e Ifyou change the output termination setting the displayed output amplitude and offset levels are automatically adjusted no error will be generated For example if you set the amplitude to 10 Vpp and then change the output termination from 50 ohms to high impedance the amplitude displayed on the function generator s front panel will double to 20 Vpp If you change from high impedance to 50 ohms the displayed amplitude will drop in half e You cannot specify the output amplitude in dBm if the output termination is currentl
114. IGger SOURce Select the trigger source for the triggered burst mode only In the triggered burst mode the function generator outputs a waveform with the specified number of cycles burst count each time a trigger is received After the specified number of cycles have been output the function generator stops and waits for the next trigger The default is IMM The SOUR query returns IMM EXT or BUS e When the Immediate internal source is selected the frequency at which the burst is generated is determined by the burst period BURS INT PER command e When the External source is selected the function generator will accept a hardware trigger applied to the rear panel Trig In connector The function generator outputs the specified number of cycles each time Trig In receives a TTL pulse with the edge polarity specified by the TRIG SLOP command see page 193 External trigger signals that occur during a burst are ignored 192 Chapter 4 Remote Interface Reference Burst Mode Commands e When the Bus software source is selected the function generator outputs one burst each time a bus trigger command is received To trigger the function generator from the remote interface either GPIB or RS 232 send the TRIG or TRG trigger command The front panel key is illuminated when the function generator is waiting for a bus trigger e When the External or Bus trigger source is selected the burst count and
115. M BORD SWAP the least significant byte LSB of each data point is assumed first Most computers use the swapped byte order 202 Chapter 4 Remote Interface Reference Arbitrary Waveform Commands FORMat BORDer NORMa1 SWAPped FORMat BORDer Used for binary block transfers only Select the byte order for binary transfers in the block mode using the DATA DAC command The default is NORM The BORD query returns NORM or SWAP In NORM byte order default the most significant byte MSB of each data point is assumed first In SWAP byte order the least significant byte LSB of each data point is assumed first Most computers use the swapped byte order The function generator represents binary data as signed 16 bit integers which are sent as two bytes Therefore each waveform data point requires 16 bits which must be transferred as two bytes on the function generator s 8 bit interface DATA COPY lt destination arb name gt VOLATILE Copy the waveform from volatile memory to the specified name in non volatile memory The source for the copy is always volatile You cannot copy from any other source and you cannot copy to volatile The arb name may contain up to 12 characters The first character must be a letter A Z but the remaining characters can be numbers 0 9 or the underscore character _ Blank spaces are not allowed If you specify a name with more than 12
116. Output pulse width 100e 6 g Arb Output pulse tran 10e 6 F Arb Output func pulse Arb Output output state on r For i 1 To 20 d Arb Output puls tran amp Sleep 300 i Next i Check_Errors r MsgBox Pulse Waveform with variable Edge Continued 0 00001 i 0 000001 Configure for Hi Z load 1MHz Sine 1Vpp OVdc offset Modulating signal Ramp Modulating frequency 10kHz Modulating depth 80 Turn ON AM modulation Routine checks for errors Example Turn OFF AM modulation Configure for 50 ohm load 20kHz Sine 1Vpp OVdc Offset FM deviation 20kHz FM Modulating Freq 1kHz Turn ON FM modulation Routine checks for errors Example Turn OFF FM modulation 1 second sweep time Start frequency 100Hz Stop frequency 20kHz Turn ON sweeping Routine checks for errors 33250A Example Turn OFF sweeping Disable Output BNC Low OV High 0 75V lms intervals 100us pulse width Edge time 10us Select Function Pulse Enable Output BNC Vary edge by lusec steps Wait 300msec Routine checks for errors Times vbOKOnly 33250A Example 283 Chapter 6 Application Programs Example Microsoft Visual Basic for Windows Triggered Burst Arb Output output state off Arb Output output sync off Arb Output func square Arb Output frequency 20e3 Arb Output volt 1 volt offset 0 Arb Output func square dcycle 20 Arb Output trig sour bus Arb Output burst ncycles 3 Arb Output
117. RMal INVerted BURSt GATE POLarity Select whether the function generator uses true high or true low logic levels on the rear panel Trig In connector for an externally gated burst The default is NORM true high logic The POL query returns NORM or INV OUTPut TRIGger SLOPe POSitive NEGative OUTPut TRIGger SLOPe Select a rising or falling edge for the trigger out signal When enabled using the OUTP TRIG command see below a TTL compatible square waveform with the specified edge is output from the rear panel Trig Out connector at the beginning of the sweep or burst Select POS to output a pulse with a rising edge or select NEG to output a pulse with a falling edge The default is POS The SLOP query returns POS or NEG e When the Immediate internal trigger source is selected TRIG SOUR IMM command the function generator outputs a square waveform with a 50 duty cycle from the Trig Out connector at the beginning of the sweep or burst The period of the waveform is equal to the specified sweep time SWE TIME command or burst period BURS INT PER command e When the External trigger source is selected TRIG SOUR EXT command the function generator automatically disables the trigger out signal The rear panel Trig Out connector cannot be used for both operations at the same time an externally triggered waveform uses the same connector to trigger
118. Sync signal follows the external gate signal However note that the signal will not go to a TTL low until the end of the last cycle may not be the zero crossing point if the waveform has an associated start phase Front Panel Operation Press viiy and select the Sync softkey again to toggle between off and on Remote Interface Operation OUTPut SYNC OFF ON Setting is stored in non volatile memory 63 Chapter 3 Features and Functions Pulse Waveforms Pulse Waveforms A shown below a pulse waveform consists of a period a pulse width a rising edge and a falling edge 90 90 50 50 a Pulse Width ee er 10 10 EREA gt Rise Time Fall Time Period Pulse Period e Pulse period 20 ns to 2000 seconds The default is 1 ms e The specified period must be greater than the sum of the pulse width and the edge time as shown below The function generator will adjust the pulse width and edge time as needed to accommodate the specified period Period gt Pulse Width 1 6 X Edge Time e Function Limitations If you change to a function whose minimum period is greater than that for a pulse waveform the period is adjusted to the minimum value allowed for the new function For example if you output a pulse waveform with a period of 50 ns and then change to the ramp function the function generator will automatically adjust the period to 1 us the lower limit for ram
119. Tus PRESet PSC 0 1 PSC xORC Parameters shown in bold are selected following a RST reset command 140 Chapter 4 Remote Interface Reference SCPI Command Summary Calibration Commands see page 239 for more information CALibration CALibration SECure STATe OFF ON lt code gt SECure STATe zS SECure CODE lt new code gt S S ETup lt O 1 2 3 115 gt SETup VALue lt value gt VALue COUNt STRing lt quoted string gt STRing IEEE 488 2 Common Commands CLS R SE lt enable value gt XF 5 F 4 n IDN LRN OPC OPC PSE POKL PSC RST SAV 011121314 State 0 is the instrument state at power down RCL 0 1 2 31 4 States 1 through 4 are user defined states STB SRE lt enable value gt SRE TRG TST Parameters shown in bold are selected following a RST reset command 141 Chapter 4 Remote Interface Reference Simplified Programming Overview Simplified Programming Overview This section gives an overview of the basic techniques used to program the function generator over the remote interface This section is only an overview and does not give all of the details you will need to write your own application programs Refer to the remainder of this chapter and also the application examples in chapter 6 for more details You may also want to
120. V command The carrier frequency must always be greater than or equal to the frequency deviation 263 222 222 222 222 222 222 Chapter 5 Error Messages Execution Errors Data out of range marker confined to sweep span value clipped to This generic message indicates that the specified marker frequency is outside the range of the start frequency and stop frequency The marker frequency must be between the specified start frequency and stop frequency If you attempt to set the marker frequency to a frequency not in this range the function generator will automatically set the marker frequency equal to the start frequency or stop frequency whichever is closer This error is generated only when both the sweep mode and the marker frequency are enabled Data out of range pulse width value clipped to This generic message indicates that the desired pulse width is limited to an upper or lower boundary which is usually dictated by the period of the pulse waveform Data out of range pulse edge time value clipped to This generic message indicates that the desired edge time is limited to an upper or lower boundary which is usually dictated by the pulse width and or period of the pulse waveform Data out of range FM deviation value clipped to This generic message indicates that the desired FM deviation is limited to a lower or upper boundary as set by the current function s frequency
121. Visual C for Windows el Using the Status Registers printf Using the Status Registers n TOO0bj gt Output apply sin 10e3 1 0 10kHz Sine wave 1Vpp TOObj gt Output trig sour bus Bus Trigger in Burst TOObj gt Output burst incycles 50000 50000 cycles x 0 1 5s TOObj gt Output burst stat on Turn ON burst mode TOOb4j gt Output ese 1 Operation complete enabled TOObj gt Output sre 32 Operation complete sets SRQ Check_Errors I00b 4 Routine check for errors IOObj gt 0utput trg opc OPC signals end of TRG _variant_t Stb Sth VvE VI IZ Force Enter to convert to Short while 1 TOObj gt Output stb Request Status Byte TOObj gt Enter amp Stb K Read Status Byte if short Stb amp 0x40 Test for Master Summary Bit break printf End of Program n catch _com_error amp e _bstr_t dsp e Description _bstr_t emsg e ErrorMessage fprintf stderr COM Exception occurred during processing nDescription s nMessage s n char dsp char emsg CoUninitialize return 0 292 Tutorial Tutorial In order to achieve the best performance from the Agilent 33250A it may be helpful for you to gain a better understanding of the internal operations of the instrument This chapter describes basic signal generation concepts and gives specific details on the internal operatio
122. Windows Download a 20 point Arbitrary waveform using ASCII printf Download a 20 point Arbitrary waveform using ASCII n Download 20 point waveform double Real_array 20 Fill_array Real_array IWritePtr pWrite I00bj gt Write pWrite gt Command data volatile VARIANT_FALSE Command into buffer for int i 0 i2 lt 2037 24 pWrite gt PutArgument i Real_array i Comma separated list to buffer pWrite gt Send Send buffer to the instrument TOObj gt Output func user volatile Select downloaded waveform TOObj gt Output apply user 10e63 1 0 Output waveform 10kHz 1Vpp Check_Errors I00b 4 Routine check for errors Pause Download a 6 point arbitrary waveform using Binary fe printf Download a 6 point Arbitrary waveform using Binary n long Len _variant_t DataArray 2047 2047 2047 2047 2047 2047 SAFEARRAY pBlock Create SCPI command with Binary block appended on end Len IO0Utils gt CreateIEEEBlock DataArray IIOUtils_Short IIOUtils_BigEndian _variant_t data dac volatile amp pBlock TOObj gt WriteBytes Len amp pBlock Send command and data SleepEx 100 0 Wait 100msec for interface for RS 232 only TOObj gt Output apply user 5000 1 0 Output waveform 5kHz 1Vpp Check_Errors I00b 4 Routine check for errors Pause Continued 291 Chapter 6 Application Programs Example Microsoft
123. ain e RTS CTS This mode operates the same as the DTR DSR mode but uses the RTS request to send and CTS clear to send lines on the RS 232 connector instead When the CTS line goes true the function generator sends data over the interface When the line goes false the function generator stops sending information typically within six characters The function generator sets the RTS line false when the input buffer is almost full about 100 characters and releases the line when space is available again 121 Chapter 3 Features and Functions Remote Interface Configuration e XON XOFF This mode uses special characters embedded in the data stream to control the flow If the function generator is addressed to send data it continues sending data until the XOFF character 13H is received When the XON character 11H is received the function generator resumes sending data e The handshake selection is stored in non volatile memory and does not change when power has been off or after a remote interface reset e To download binary data for arbitrary waveforms over the RS 232 interface you can use any handshake mode except XON XOFF Be sure to select Parity None 8 data bits You must also insert a pause of approximately 1 ms between sending the header and sending the binary block e Front Panel Operation Press and then select the Handshake softkey from the I O menu 122 Chapter 3 Features and Fun
124. al EXTernal 77 Chapter 3 Features and Functions Frequency Shift Keying FSK Modulation Frequency Shift Keying FSK Modulation You can configure the function generator to shift its output frequency between two preset values using FSK modulation The rate at which the output shifts between the two frequencies called the carrier frequency and the hop frequency is determined by the internal rate generator or the signal level on the rear panel Trig In connector For more information on the fundamentals of FSK Modulation refer to chapter 7 Tutorial To Select FSK Modulation e The function generator will allow only one modulation mode to be enabled at a time For example you cannot enable FSK and AM at the same time When you enable FSK the previous modulation mode is turned off e The function generator will not allow FSK to be enabled at the same time that sweep or burst is enabled When you enable FSK the sweep or burst mode is turned off e Front Panel Operation You must enable FSK before setting up any of the other modulation parameters Press hod and then select FSK using the Type softkey The FSK waveform is output using the present settings for the carrier frequency output amplitude and offset voltage e Remote Interface Operation To avoid multiple waveform changes enable FSK after you have set up the other modulation parameters FSKey STATe OFF ON 78
125. ally modulated AM and FM the Sync signal is referenced to the modulating waveform not the carrier and is a square waveform with a 50 duty cycle The Sync signal is a TTL high during the first half of the modulating waveform e For externally modulated AM and FM the Sync signal is referenced to the carrier waveform not the modulating waveform and is a square waveform with a 50 duty cycle 62 Chapter 3 Features and Functions Output Configuration For FSK the Sync signal is referenced to the hop frequency and is a square waveform with a 50 duty cycle The Sync signal is a TTL high on the transition to the hop frequency For frequency sweeps with Marker Off the Sync signal is a square waveform with a 50 duty cycle The Sync signal is a TTL high at the beginning of the sweep and goes low at the midpoint of the sweep The frequency of the sync waveform equals the specified sweep time For frequency sweeps with Marker On the Sync signal is a TTL high at the beginning of the sweep and goes low at the marker frequency For a triggered burst the Sync signal is a TTL high when the burst begins The Sync signal is a TTL low at the end of the specified number of cycles may not be the zero crossing point if the waveform has an associated start phase For an infinite count burst the Sync signal is the same as for a continuous waveform For an externally gated burst the
126. anel Operation Press witiy and then select the Number Format softkey from the System menu 116 Chapter 3 Features and Functions System Related Operations Firmware Revision Query You can query the function generator to determine which revision of firmware is currently installed The revision code contains five numbers in the form m mm L II f ff gg p m mm Main firmware revision number III f ff TO processor firmware revision number 99 p Loader firmware revision number Gate array revision number Printed circuit board revision number e Front Panel Operation Press utility and then select the Cal Info softkey from the Test Cal menu The revision code is listed as one of the messages on the front panel display e Remote Interface Operation Use the following command to read the function generator s firmware revision numbers be sure to dimension a string variable with at least 50 characters IDN This command returns a string in the form Agilent Technologies 33250A 0 m mm L Il f ff gg p SCPI Language Version Query The function generator complies with the rules and conventions of the present version of SCPI Standard Commands for Programmable Instruments You can determine the SCPI version with which the instrument is in compliance by sending a query from the remote interface You cannot query the SCPI version from the front panel e Remote Interface Operation SYSTem VERSi
127. ar Sweep n TOObj gt Output Sweep time 1 TOObj gt Output freq start 100 TOObj gt Output freq stop 20000 TOObj gt Output Sweep stat on Check_Errors I00bj Pause TOObj gt Output Sweep stat off Pulse period with variable Edge Times bf printf Pulse Waveform with variable Edge Times n TOObj gt Output output state off TOObj gt Output volt low O volt high 0 75 TOObj gt Output pulse period le 3 TOObj gt Output pulse width 100e 6 TOObj gt Output pulse tran 10e 6 TOObj gt Output func pulse TOObj gt Output output state on for i 0 i lt 10 it sprintf cmds puls tran f n 0 00001 0 000001 float i TO0O0bj gt Output cmds SleepEx 300 0 Check_Errors I00bj Pause Triggered Burst printf Triggered Burst n OObj gt Output output state off OObj gt Output output synce off OObj gt Output func square O0Obj gt Output frequency 20e3 OObj gt Output volt 1 volt offset 0 O0Obj gt Output func square dcycle 20 OObj gt Output trig sour bus OObj gt Output burst ncycles 3 0Obj gt Output burst state on OObj gt Output output state on O0Obj gt Output output syne on Check_Errors I00b for int i 1 i lt 20 i TOObj gt Output trg SleepEx 100 0 Pause Continued 290 Chapter 6 Application Programs Example Microsoft Visual C for
128. arithmic spacing You can also configure the function generator to output a single sweep one pass from start frequency to stop frequency by applying an external or manual trigger The function generator can produce a frequency sweep for sine square ramp or arbitrary waveforms pulse noise and de are not allowed For more information on the fundamentals of a sweep refer to chapter 7 Tutorial To Select Sweep e The function generator will not allow the sweep mode to be enabled at the same time that burst or any modulation mode is enabled When you enable sweep the burst or modulation mode is turned off e Front Panel Operation You must enable sweep before setting up any of the other sweep parameters Press to output a sweep using the present settings for frequency output amplitude and offset e Remote Interface Operation To avoid multiple waveform changes enable the sweep mode after you have set up the other parameters SWEep STATe OFF ON 82 Chapter 3 Features and Functions Frequency Sweep Start Frequency and Stop Frequency The start frequency and stop frequency set the upper and lower frequency bounds for the sweep The function generator begins at the start frequency sweeps to the stop frequency and then resets back to the start frequency e Start and Stop frequencies 1 uHz to 80 MHz limited to 1 MHz for ramps and 25 MHz for arbitrary waveforms The sweep is phase continuous over the f
129. at make up a single character The frame is defined as the bits from the start bit to the stop bit inclusively Within the frame you can select the baud rate number of data bits and parity type The function generator uses the following frame formats for seven and eight data bits Parity Start f Parity Stop Even Odd Bit 7 Data Bits Bit Bit Parity Start Stop None Bit 8 Data Bits Bit Connection to a Computer To connect the function generator to a computer you must have the proper interface cable Most computers are DTE Data Terminal Equipment devices Since the function generator is also a DTE device you must use a DTE to DTE interface cable These cables are also called null modem modem eliminator or crossover cables The interface cable must also have the proper connector on each end and the internal wiring must be correct Connectors typically have 9 pins DB 9 connector or 25 pins DB 25 connector with a male or female pin configuration A male connector has pins inside the connector shell and a female connector has holes inside the connector shell If you cannot find the correct cable for your configuration you may have to use a wiring adapter If you are using a DTE to DTE cable make sure the adapter is a straight through type Typical adapters include gender changers null modem adapters and DB 9 to DB 25 adapters 221 Chapter 4 Remote Interface Reference RS
130. ated If you change from high impedance to 50 ohms the displayed offset will drop in half See the OUTP LOAD command on page 163 for more information e Arbitrary Waveform Limitations For arbitrary waveforms the maximum offset and amplitude will be limited if the waveform data points do not span the full range of the output DAC Digital to Analog Converter For example the built in Sinc waveform does not use the full range of values between 1 and therefore its maximum offset is limited to 4 95 volts into 50 ohms 158 Chapter 4 Remote Interface Reference Output Configuration Commands e You can also set the offset by specifying a high level and low level For example if you set the high level to 2 volts and the low level to 3 volts the resulting amplitude is 5 Vpp with an associated offset voltage of 500 mV See the VOLT HIGH and VOLT LOW commands below for more information e To output a dc voltage level select the de voltage function using the FUNC DC command and then set the offset voltage level using the VOLT OFFS command You can set the de level to any value between 5 Vdc into 50 ohms or 10 Vdc into an open circuit VOLTage HIGH lt voltage gt MINimum MAXimum HIGH MINimum MAXimum LOW lt voltage gt MINimum MAXimum LOW MINimum MAXimum Set the high or low voltage levels For all functions the default high level is 50 mV and the default low level is 50 mV MIN selects the
131. aveform e Remote Interface Operation BURSt NCYCles lt cycles gt INFinity MINimum MAXimum 93 Chapter 3 Features and Functions Burst Mode Burst Period The burst period defines time from the start of one burst to the start of the next burst Used in the internal triggered burst mode only Keep in mind that burst period is different than the waveform frequency which specifies the frequency of the bursted signal e Burst period 1 ps to 500 seconds The default is 10 ms e The burst period setting is used only when Internal triggering is enabled The burst period is ignored when manual or external triggering is enabled or when the gated burst mode is selected e Itis not possible to specify a burst period which is too short for the function generator to output with the specified burst count and frequency see below If the burst period is too short the function generator will automatically adjust it as needed to continuously re trigger the burst Burst Count aoe a D00 Waveform Frequency A Burst Period gt e Front Panel Operation To set the burst period press the Burst Period softkey and then use the knob or numeric keypad to enter the period e Remote Interface Operation BURSt INTernal PERiod lt seconds gt MINimum MAXimum 94 Chapter 3 Features and Functions Burst Mode Burst Phase The burst phase defines the starting phase of the burst Burst phase 360 degrees to 360 de
132. aveform with varying edge times e Configuring a triggered burst waveform e Downloading ASCII and binary data for an arbitrary waveform e Using the 33250A status registers The example programs are also included on the CD ROM shipped with the Agilent 33250A see the examples directory The examples are placed in their own sub directory based on programming language The Basic directory contains one ASCII file and you can use the BASIC command GET filename to retrieve the example program The other two example sub directories contain all of the project files necessary for use with Microsoft Visual Basic or Visual C 276 Chapter 6 Application Programs Introduction The installation procedure on the CD ROM gives you the option to install the ActiveX components for instrument control These components are required for Visual Basic and Visual C All of the required hardware level drivers such as the SICL Standard Instrument Control Language libraries or the NI 488 2 libraries should have been loaded when you installed your GPIB interface card If you are using the RS 282 interface the SICL or NI 488 2 libraries also give you access to the RS 232 ports on your PC and make those drivers available for all three languages The instrument is shipped with both a GPIB interface and an RS 232 interface Only one interface can be enabled at a time The GPIB interface is selected when the instrument is shipped from the
133. before setting up any of the other burst parameters Press ust to output a burst using the present settings for frequency output amplitude and offset voltage e Remote Interface Operation To avoid multiple waveform changes enable the burst mode after you have set up the other parameters BURSt STATe OFF ON 89 Chapter 3 Features and Functions Burst Mode Burst Type You can use burst in one of two modes as described below The function generator enables one burst mode at a time based on the trigger source and burst source that you select see the table below e Triggered Burst Mode In this mode default the function generator outputs a waveform with a specified number of cycles burst count each time a trigger is received After the specified number of cycles have been output the function generator stops and waits for the next trigger You can configure the function generator to use an internal trigger to initiate the burst or you can provide an external trigger by pressing the front panel key applying a trigger signal to the rear panel Trig In connector or sending a software trigger command from the remote interface e External Gated Burst Mode In this mode the output waveform is either on or off based on the level of the external signal applied to the rear panel Trig In connector When the gate signal is true the function generator outputs a continuous waveform When the gate signal goes false t
134. below Select the shape of the modulating waveform You can modulate the carrier with a sine square ramp noise or arbitrary waveform pulse and dc are not allowed Use the AM INT FUNC command to select the modulating waveshape Set the modulating frequency Set the modulating frequency to any value from 2 mHz to 20 kHz using the AM INT FREQ command Set the modulation depth Set the modulation depth also called percent modulation to any value from 0 to 120 using the AM DEPT command Enable AM modulation After you have set up the other modulation parameters use the AM STAT ON command to enable AM 169 Chapter 4 Remote Interface Reference Amplitude Modulation AM Commands AM Commands Use the APPLy command or the equivalent FUNC FREQ VOLT and VOLT OFFS commands to configure the carrier waveform AM SOURce INTernal EXTernal AM SOURce Select the source of the modulating signal The function generator will accept an internal or external modulation source The default is INT The SOUR query returns INT or EXT e Ifyou select the External source the carrier waveform is modulated with an external waveform The modulation depth is controlled by the 5V signal level present on the rear panel Modulation In connector For example if you have set the modulation depth to 100 using the AM DEPT command then when the modulating signal is at 5 volts the output wi
135. bled at the same time When you enable a modulation sweep or burst mode all other modes are turned off Settings conflict FSK turned off by selection of other mode or modulation The function generator will allow only one modulation sweep or burst mode to be enabled at the same time When you enable a modulation sweep or burst mode all other modes are turned off Settings conflict FM turned off by selection of other mode or modulation The function generator will allow only one modulation sweep or burst mode to be enabled at the same time When you enable a modulation sweep or burst mode all other modes are turned off Settings conflict AM turned off by selection of other mode or modulation The function generator will allow only one modulation sweep or burst mode to be enabled at the same time When you enable a modulation sweep or burst mode all other modes are turned off 255 221 221 221 221 221 221 221 Chapter 5 Error Messages Execution Errors Settings conflict sweep turned off by selection of other mode or modulation The function generator will allow only one modulation sweep or burst mode to be enabled at the same time When you enable a modulation sweep or burst mode all other modes are turned off Settings conflict not able to modulate this function The function generator cannot generate a modulated waveform using the pulse noise or de voltage functions
136. burst phase remain in effect but the burst period is ignored e The APPLy command automatically sets the trigger source to Immediate equivalent to TRIG SOUR IMM command e To ensure synchronization when the Bus source is selected send the WAL wait command When the WAI command is executed the function generator waits for all pending operations to complete before executing any additional commands For example the following command string guarantees that the first trigger is accepted and the operation is executed before the second trigger is recognized TRIG SOUR BUS TRG WAI TRG WAI e You can use the OPC operation complete query command or the OPC operation complete command to signal when the burst is complete The OPC command returns 1 to the output buffer when the burst is complete The OPC command sets the Operation Complete bit bit 0 in the Standard Event register when the burst is complete TRIGger DELay lt seconds gt MINimum MAXimum TRIGger DELay MINimum MAXimum Insert a time delay between the receipt of the trigger and the start of the burst waveform used in triggered burst mode only Select from 0 seconds to 85 seconds The default delay is 0 MIN 0 seconds MAX 85 seconds The DEL query returns the trigger delay in seconds TRIGger SLOPe POSitive NEGative TRIGger SLOPe Select whether the function generator uses the rising edge or falling edge of the trigger signa
137. but it is processed like any other instrument command This command returns the same result as a Serial Poll but the Master Summary bit bit 6 is not cleared by the STB command SRE lt enable value gt SRE Enable bits in the Status Byte to generate a Service Request To enable specific bits you must write a decimal value which corresponds to the binary weighted sum of the bits in the register The selected bits are summarized in the Master Summary bit bit 6 of the Status Byte Register If any of the selected bits change from 0 to 1 a Service Request signal is generated The SRE query returns a decimal value which corresponds to the binary weighted sum of all bits enabled by the SRE command e A CLS clear status does not clear the enable register but it does clear all bits in the event register e A STATus PRESet does not clear the bits in the Status Byte enable register e A PSC 0 preserves the contents of the enable register through power cycles 235 Chapter 4 Remote Interface Reference Status Reporting Commands Questionable Data Register Commands See the table on page 231 for the register bit definitions STATus QUEStionable CONDition Query the condition register in this group This is a read only register and bits are not cleared when you read the register A query of this register returns a decimal value which corresponds to the binary weighted s
138. by your computer or modem You can select the handshake mode from the front panel only e Select one of the following None DTR DSR factory setting Modem RTS CTS or XON XOFF e None In this mode data is sent and received over the interface without any flow control used When using this method use a slower baud rate lt 9600 baud and avoid sending more than 128 characters without stopping or reading a response e DTR DSR Inthis mode the function generator monitors the state of the DSR data set ready line on the RS 232 connector When the line goes true the function generator sends data over the interface When the line goes false the function generator stops sending information typically within six characters The function generator sets the DTR line false when the input buffer is almost full about 100 characters and releases the line when space is available again e Modem This mode uses the DTR DSR and RTS CTS lines to control the flow of data between the function generator and a modem When the RS 232 interface is selected the function generator sets the DTR line true The DSR line is set true when the modem is on line The function generator sets the RTS line true when it is ready to receive data The modem sets the CTS line true when it is ready to accept data The function generator sets the RTS line false when the input buffer is almost full about 100 characters and releases the line when space is available ag
139. ce or you may have used a blank space instead of a comma Examples TRIG SOUR BUS or APPL SIN 1 1000 GET not allowed A Group Execute Trigger GET is not allowed within a command string Parameter not allowed More parameters were received than were expected for the command You may have entered an extra parameter or added a parameter to a command that does not require a parameter Example APPL 10 Missing parameter Fewer parameters were received than were expected for this command You have omitted one or more parameters that are required for this command Example OUTP LOAD 249 112 113 123 124 128 131 138 148 151 Chapter 5 Error Messages Command Errors Program mnemonic too long A command header was received which contained more than the maximum 12 characters allowed This error is also reported when a character type parameter is too long Example OUTP SYNCHRONIZATION ON Undefined header A command was received that is not valid for this instrument You may have misspelled the command or it may not be a valid command If you are using the short form of the command remember that it may contain up to four letters Example TRIGG SOUR BUS Exponent too large A numeric parameter was found whose exponent was larger than 32 000 Example BURS NCYCL 1E34000 Too many digits A numeric parameter was found whose mantissa contained more than 255 digits excluding leading zeros
140. cing the amplitude below the expected range change 304 Chapter 7 Tutorial Ground Loops As shown below the 33250A has a fixed series output impedance of 50Q forming a voltage divider with the load resistance Agilent 33250A 509 De m S l aac i OU Veen R OM Ele As a convenience you can specify the load impedance as seen by the function generator and thereby display the correct load voltage If the actual load impedance is different than the value specified the displayed amplitude offset and high low levels will be incorrect Variations in source resistance are measured and taken into account during an instrument calibration Therefore the accuracy of the load voltage depends primarily on the accuracy of the load resistance as shown below 50 SAC age ie Ry 50 xA R Ground Loops Except for its remote interface connectors and trigger connector the 33250A is isolated from chassis earth ground This isolation helps to eliminate ground loops in your system and also allows you to reference the output signal to voltages other than ground The illustration on the following page shows the function generator connected to a load through a coaxial cable Any difference in ground potentials Vqnp will tend to make current Iqnp flow in the shield of the cable thus causing a voltage drop due to the shield s impedance Zshiel a The resulting voltage drop IGND X Zghielg appear
141. command performs the following operations e Sets the trigger source to Immediate equivalent to sending the TRIG SOUR IMM command e Turns off any modulation sweep or burst mode currently enabled and places the instrument in the continuous waveform mode e Turns on the Output connector OUTP ON command but does not change the output termination setting OUTP LOAD command e Overrides the voltage autorange setting and automatically enables autoranging VOLT RANG AUTO command e For square waveforms overrides the current duty cycle setting and automatically selects 50 FUNC SQU DCYC command e For ramp waveforms overrides the current symmetry setting and automatically selects 100 FUNC RAMP SYMM command The syntax statements for the APPLy command are shown on page 149 144 Chapter 4 Remote Interface Reference Using the APPLy Command Output Frequency e For the frequency parameter of the APPLy command the output frequency range depends on the function specified You can substitute MINimum MAXimum or DEFault in place of a specific value for the frequency parameter MIN selects the lowest frequency allowed for the function specified and MAX selects the highest frequency allowed The default frequency is 1 kHz for all functions Function Minimum Frequency Maximum Frequency Sine 1 wHz 80 MHz Square 1 wHz 80 MHz Ramp 1 wHz 1 MHz Pulse 500 uHz 50 MHz Noise DC Not Applicable No
142. complete listing of the error messages e Errors are retrieved in first in first out FIFO order The first error returned is the first error that was stored Errors are cleared as you read them The function generator beeps once each time an error is generated unless disabled using the SYST BEEP STAT command e If more than 20 errors have occurred the last error stored in the queue the most recent error is replaced with Queue overflow No additional errors are stored until you remove errors from the queue If no errors have occurred when you read the error queue the function generator responds with No error e The error queue is cleared by the CLS clear status command or when the power is cycled The errors are also cleared when you read the queue The error queue is not cleared by a reset RST command e Errors have the following format the error string may contain up to 255 characters 113 Undefined header 213 Chapter 4 Remote Interface Reference System Related Commands IDN Read the function generator s identification string which contains four fields separated by commas The first field is the manufacturer s name the second field is the model number the third field is not used always Q and the fourth field is a revision code which contains five numbers separated by dashes e The command returns a string with the following format be sure to dimension a strin
143. corresponds to the binary weighted sum of all bits set in the register ESE lt enable value gt ESE Enable bits in the Standard Event Status Register to be reported in the Status Byte The selected bits are summarized in the Standard Event bit bit 5 of the Status Byte Register The ESE query returns a decimal value which corresponds to the binary weighted sum of all bits enabled by the ESE command e A CLS clear status does not clear the enable register but it does clear all bits in the event register e A STATus PRESet does not clear the bits in the Status Byte enable register e A PSC 0 preserves the contents of the enable register through power cycles 237 Chapter 4 Remote Interface Reference Status Reporting Commands Miscellaneous Status Register Commands CLS Clear the event register in all register groups This command also clears the error queue and cancels a OPC operation STATus PRESet Clear all bits in the Questionable Data enable register and the Standard Operation enable register PSC 0 1 PSC Power On Status Clear Clear the Standard Event enable register and Status Byte condition register at power on PSC 1 When PSC 0 is in effect these two registers are not cleared at power on The default is PSC 1 The PSC query returns the power on status clear setting Returns 0 do not clear at power on or 1 clear at power
144. ctions You will find that this chapter makes it easy to look up all the details about a particular feature of the function generator Whether you are operating the function generator from the front panel or over the remote interface this chapter will be useful This chapter is divided into the following sections e Output Configuration on page 49 e Pulse Waveforms on page 64 e Amplitude Modulation AM on page 67 e Frequency Modulation FM on page 72 e Frequency Shift Keying FSK Modulation on page 78 e Frequency Sweep on page 82 e Burst Mode on page 89 e Triggering on page 98 e Arbitrary Waveforms on page 103 e System Related Operations on page 109 e Remote Interface Configuration on page 118 e Calibration Overview on page 123 e Factory Default Settings on page 127 Some knowledge of the front panel menus will be helpful before you read this chapter If you have not already read chapter 2 Front Panel Menu Operation starting on page 29 you may want to read it now Chapter 4 Remote Interface Reference starting on page 129 lists the syntax for the SCPI commands available to program the function generator Throughout this manual the following conventions are used for SCPI command syntax for remote interface programming e Square brackets indicate optional keywords or parameters e Braces enclose parameters within a command string e Triangle brackets lt gt enclose parameters
145. ctions Calibration Overview Calibration Overview This section gives a brief introduction to the calibration features of the function generator For a more detailed discussion of the calibration procedures see chapter 4 in the Agilent 33250A Service Guide Calibration Security This feature allows you to enter a security code to prevent accidental or unauthorized calibrations of the function generator When you first receive your function generator it is secured Before you can perform a calibration you must unsecure the function generator by entering the correct security code If you forget your security code you can disable the security feature by adding a jumper inside the instrument See the Agilent 33250A Service Guide for more information e The security code is set to AT33250A when the function generator is shipped from the factory The security code is stored in non volatile memory and does not change when power has been off or after a remote interface reset e The security code may contain up to 12 alphanumeric characters The first character must be a letter but the remaining characters can be letters numbers or an underscore _ You do not have to use all 12 characters but the first character must always be a letter 123 Chapter 3 Features and Functions Calibration Overview To Unsecure for Calibration You can unsecure the function generator either from the front panel or over the re
146. cy and deviation must be less than or equal to the maximum frequency for the selected function plus 100 kHz 80 1 MHz for sine and square 1 1 MHz for ramp and 25 1 MHz for arbitrary waveforms If you attempt to set the deviation to a value that is not valid the function generator will limit it to the maximum value allowed with the present carrier frequency Front Panel Operation After enabling FM press the Freq Dev softkey Then use the knob or numeric keypad to enter the desired deviation Remote Interface Operation FM DEViation lt peak deviation in Hz gt MINimum MAXimum 76 Chapter 3 Features and Functions Frequency Modulation FM Modulating Source The function generator will accept an internal or external modulation source for FM e Modulating source Internal or External The default is Internal e Ifyou select the External source the carrier waveform is modulated with an external waveform The frequency deviation is controlled by the 5V signal level present on the rear panel Modulation In connector For example if you have set the deviation to 100 kHz then a 5V signal level corresponds to a 100 kHz increase in frequency Lower external signal levels produce less deviation and negative signal levels reduce the frequency below the carrier frequency Modulation In 5 V OV e Front Panel Operation After enabling FM press the Source softkey e Remote Interface Operation FM SOURce INTern
147. d BURS MODE GAT command the function generator automatically disables the trigger out signal The rear panel Trig Out connector cannot be used for both operations at the same time an externally triggered waveform uses the same connector to trigger the burst e When the Bus software trigger source is selected TRIG SOUR BUS command the function generator outputs a pulse gt 1 ps pulse width from the Trig Out connector at the beginning of each burst OUTPut TRIGger OFF ON OUTPut TRIGger Disable or enable the trigger out signal used with burst and sweep only When enabled a TTL compatible square waveform with the specified edge OUTP TRIG SLOP command is output from the rear panel Trig Out connector at the beginning of the burst The default is OFF The TRIG query returns 0 OFF or 1 ON 194 Chapter 4 Remote Interface Reference Triggering Commands Triggering Commands Applies to Sweep and Burst only See also Triggering starting on page 98 in chapter 3 TRIGger SOURce IMMediate EXTernal BUS TRIGger SOURce Select the source from which the function generator will accept a trigger The function generator will accept an immediate internal trigger a hardware trigger from the rear panel Trig In connector or a software bus trigger The default is IMM The SOUR query returns IMM EXT or BUS When the Immediate internal source is selected
148. d SQUare RAMP PULSe NOISe DC USER You can also use the APPLy command to select the function frequency amplitude and offset with a single command 50 Chapter 3 Features and Functions Output Configuration Output Frequency As shown below the output frequency range depends on the function currently selected The default frequency is 1 kHz for all functions Function Minimum Frequency Maximum Frequency Sine 1 wHz 80 MHz Square 1 wHz 80 MHz Ramp 1 wHz 1 MHz Pulse 500 wHz 50 MHz Noise DC Not Applicable Not Applicable Arbs 1 wHz 25 MHz e Function Limitations If you change to a function whose maximum frequency is less than that of the current function the frequency is adjusted to the maximum value for the new function For example if you are currently outputting an 80 MHz sine wave and then change to the ramp function the function generator will automatically adjust the output frequency to 1 MHz the upper limit for ramps e Burst Limitation For internally triggered bursts the minimum frequency is 2 mHz For sine and square waveforms frequencies above 25 MHz are allowed only with an infinite burst count e Duty Cycle Limitations For square waveforms the function generator may not be able to use the full range of duty cycle values at higher frequencies as shown below 20 to 80 frequency lt 25 MHz 40 to 60 25 MHz lt frequency lt 50 MHz 50 frequency gt 50 MHz If yo
149. d by the BURS NCYC command takes priority over the burst period as long as the burst period is not at its maximum value The function generator has increased the burst period to accommodate the specified burst count or waveform frequency 252 221 221 221 221 221 221 Chapter 5 Error Messages Execution Errors Settings conflict burst count reduced Since the burst period is currently at its maximum the function generator has reduced the burst count to allow the specified waveform frequency Settings conflict trigger delay reduced to fit entire burst The function generator has reduced the trigger delay in order to maintain the current burst period and burst count The trigger delay is the time between the receipt of the trigger and the start of the burst waveform Settings conflict triggered burst not available for noise You cannot use the noise function in the triggered burst mode Noise is allowed only in the gated burst mode Settings conflict amplitude units changed to Vpp due to high Z load The output units VOLT UNIT command cannot be set to dBm if the output termination is currently set to high impedance OUTP LOAD command The function generator has converted the units to Vpp Settings conflict trigger output disabled by trigger external When the external trigger source is selected TRIG SOUR EXT command the function generator automatically disables the trigger out s
150. d from the factory the baud rate is set to 57 600 baud You can set the baud rate from the front panel only e Select one of the following 300 600 1200 2400 4800 9600 19200 38400 57600 factory setting or 115200 baud e The baud rate selection is stored in non volatile memory and does not change when power has been off or after a remote interface reset and then select the Baud Rate e Front Panel Operation Press wiility softkey from the I O menu Parity Selection RS 232 You can select the parity for RS 232 operation When shipped from the factory the instrument is configured for no parity with 8 data bits You can set the parity from the front panel only e Select one of the following None 8 data bits Even 7 data bits or Odd 7 data bits When you set the parity you are also setting the number of data bits e The parity selection is stored in non volatile memory and does not change when power has been off or after a remote interface reset e Front Panel Operation Press v softkey from the I O menu ity and then select the Parity Bits 120 Chapter 3 Features and Functions Remote Interface Configuration Handshake Selection RS 232 You can select one of several handshake or flow control methods to coordinate the transfer of data between the function generator and your computer or modem The method that you select will be determined by the handshake mode used
151. e the carrier waveform is modulated with an external waveform The modulation depth is controlled by the 5V signal level present on the rear panel Modulation In connector For example if you have set the modulation depth to 100 then when the modulating signal is at 5 volts the output will be at the maximum amplitude When the modulating signal is at 5 volts then the output will be at the minimum amplitude Modulation In 5 V OV e Front Panel Operation After enabling AM press the Source softkey e Remote Interface Operation AM SOURce INTernal EXTernal 71 Chapter 3 Features and Functions Frequency Modulation FM Frequency Modulation FM A modulated waveform consists of a carrier waveform and a modulating waveform In FM the frequency of the carrier is varied by the instantaneous voltage of the modulating waveform For more information on the fundamentals of Frequency Modulation refer to chapter 7 Tutorial To Select FM Modulation e The function generator will allow only one modulation mode to be enabled at a time For example you cannot enable FM and AM at the same time When you enable FM the previous modulation mode is turned off e The function generator will not allow FM to be enabled at the same time that sweep or burst is enabled When you enable FM the sweep or burst mode is turned off e Front Panel Operation You must enable FM before setting up any of the other
152. e Graph Mode press CP again Grash key also serves as a key to restore front panel control after remote interface operations 23 Chapter 1 Quick Start To Output a Stored Arbitrary Waveform To Output a Stored Arbitrary Waveform There are five built in arbitrary waveforms stored in non volatile memory The following steps show you how to output the built in exponential fall waveform from the front panel For information on creating a custom arbitrary waveform refer to To Create and Store an Arbitrary Waveform on page 109 1 Select the arbitrary waveform function When you press the key to select the arbitrary waveform function a temporary message is displayed indicating which waveform is currently selected the default is exponential rise 2 Select the active waveform Press the Select Wform softkey and then press the Built In softkey to select from the five built in waveforms Then press the Exp Fall softkey The waveform is output using the present settings for frequency amplitude and offset unless you change them Exp Neg Fall Ramp Sinc Cardiac CANCEL The selected waveform is now assigned to the press this key the selected arbitrary waveform is output To quickly determine which arbitrary waveform is currently selected press Arb 24 Chapter 1 Quick Start To Use the Built In Help System To Use the Built In Help System The built in help
153. e Operation FREQuency lt frequency gt MINimum MAXimum You can also use the APPLy command to select the function frequency amplitude and offset with a single command 68 Chapter 3 Features and Functions Amplitude Modulation AM Modulating Waveform Shape The function generator will accept an internal or external modulation source for AM Modulating waveform shape internal source Sine Square Ramp Negative Ramp Triangle Noise or Arb waveform The default is Sine e Square has 50 duty cycle e Ramp has 100 symmetry Be e Triangle has 50 symmetry yes e Negative ramp has 0 symmetry You can use noise as the modulating waveshape but you cannot use noise pulse or de as the carrier waveform If you select an arbitrary waveform as the modulating waveshape the waveform is automatically limited to 8K points Extra waveform points are removed using decimation Front Panel Operation After enabling AM press the Shape softkey Remote Interface Operation AM INTernal FUNCtion SINusoid SQUare RAMP NRAMp TRIlangle NOISe USER Modulating Waveform Frequency The function generator will accept an internal or external modulation source for AM Modulating frequency internal source 2 mHz to 20 kHz The default is 100 Hz Front Panel Operation After enabling AM press the AM Freq softkey Remote Interface Operation AM INTernal FREQuency lt frequency gt MINimum MAXimum
154. e command does not have a query form SYSTem LOCal Place the function generator in the local mode for RS 232 operation All keys on the front panel are fully functional while in the local mode SYSTem RWLock Place the function generator in the remote mode for RS 232 operation and disable all front panel keys lt Break gt Clear the operation in progress over the RS 232 interface and discard any pending output data This is equivalent to the IEEE 488 Device Clear operation over the GPIB interface 218 Chapter 4 Remote Interface Reference RS 232 Interface Configuration RS 232 Interface Configuration See also Remote Interface Configuration on page 118 in chapter 3 This section contains information to help you use the function generator over the RS 232 interface The programming commands for RS 232 operation are listed on the previous page RS 232 Configuration Overview Configure the RS 232 interface using the parameters shown below Use the front panel Utility I O menu to select the baud rate parity number of data bits and handshake mode see page 45 for more information on using the front panel menus Baud Rate 300 600 1200 2400 4800 9600 19200 38400 57600 factory setting 115200 Parity Data Bits None 8 data bits factory setting Even 7 data bits Odd 7 data bits Handshake Mode None no handshake mode DTR DSR factory setting Modem RTS CTS XON XOFF Number of Start Bi
155. e function generator to recall the power down state when power is restored press and select the Pwr On Last softkey You can assign a custom name to each of the four storage locations e The custom name can contain up to 12 characters The first character must be a letter but the remaining characters can be letters numbers or the underscore character _ e To add additional characters press the right arrow key until the cursor is to the right of the existing name and then turn the knob e To delete all characters to the right of the cursor press the key Remote Interface Operation SAV 0 112 3 4 State 0 is the instrument state at power down RCL 0 112 3 4 States 1 2 3 and 4 are user defined states To assign a custom name to a stored state to be recalled from the front panel send the following command From the remote interface you can only recall a stored state using a number 0 through 4 MEM STATE NAME 1 TEST_WFORM_1 To configure the function generator to automatically recall the power down state when power is restored send the following command MEMory STATe RECall AUTO ON 111 Chapter 3 Features and Functions System Related Operations Error Conditions A record of up to 20 command syntax or hardware errors can be stored in the function generator s error queue See chapter 5 for a complete listing of the errors Errors are retrieved in first in first
156. e is selected the function generator will accept a hardware trigger applied to the rear panel Trig In connector The function generator initiates one sweep each time Trig In receives a TTL pulse 312 Chapter 7 Tutorial Frequency Sweep A sweep consists of a finite number of small frequency steps Since each step takes the same amount of time longer sweep times result in smaller steps and therefore better resolution The number of discrete frequency points in the sweep is automatically calculated by the function generator and is based on the sweep time you select Sync Output Main Output Frequency Sweep For triggered sweeps the trigger source can be an external signal the key or a command received from the remote interface The input for external trigger signals is the rear panel Trig In connector This connector accepts TTL compatible levels and is referenced to chassis ground not floating ground When not used as an input the Trig In connector can be configured as an output to enable the 33250A to trigger other instruments at the same time as its internal trigger occurs 313 Chapter 7 Tutorial Frequency Sweep Syne and Marker Signals The output from the front panel Sync connector goes high at the beginning of each sweep If you have disabled the Marker function the Sync signal goes low at the midpoint of the sweep However if you have enabled the Marker function the Sync
157. e measurement outside of the expected range 269 615 616 617 618 to 625 626 to 630 Chapter 5 Error Messages Self Test Errors Self test failed primary phase locked loop This error indicates that the primary PLL U901 U903 has failed to lock Self test failed secondary phase locked loop at 200 MHz This error indicates that the secondary PLL U904 U907 which is used for the pulse function has failed to lock at 200 MHz Self test failed secondary phase locked loop at 100 MHz This error indicates that the secondary PLL U904 U907 which is used for the pulse function has failed to lock at 100 MHz 618 Self test failed display contrast DAC 619 Self test failed leading edge DAC 620 Self test failed trailing edge DAC 621 Self test failed square wave threshold DAC 622 Self test failed time base calibration DAC 623 Self test failed dc offset DAC 624 Self test failed null DAC 625 Self test failed amplitude DAC These errors indicate a malfunctioning system DAC U701 U705 DAC MUX logic circuit or DAC MUX U706 U708 U603 channels These self tests use the internal ADC to verify that the system DAC s are operating properly For each DAC the readings are taken at 25 50 and 75 of full scale 626 Self test failed analog digital path select relay 627 Self test failed 10 dB attenuator path 628 Self test failed 20 dB attenuator path 629 Self test failed 20 dB amplifier path
158. e modulating waveform is a square wave with a 50 duty cycle FSKey INTernal RATE lt rate in Hz gt MINimum MAXimum FSKey INTernal RATE MINimum MAXimum Set the rate at which the output frequency shifts between the carrier and hop frequency Select from 2 mHz to 1 MHz The default is 10 Hz MIN 2 mHz MAX 1 MHz The RATE query returns the FSK rate in hertz e The FSK rate is only used when the Internal source is selected FSK SOUR INT command and is ignored when the external source is selected FSK SOUR EXT command FSKey STATe OFF ON FSKey STATe Disable or enable FSK modulation To avoid multiple waveform changes you can enable FSK after you have set up the other modulation parameters The default is OFF The STAT query returns 0 OFF or 1 ON e The function generator will allow only one modulation mode to be enabled at a time For example you cannot enable FSK and AM at the same time When you enable FSK the previous modulation mode is turned off e The function generator will not allow FSK to be enabled at the same time that sweep or burst is enabled When you enable FSK the sweep or burst mode is turned off 178 Chapter 4 Remote Interface Reference Frequency Sweep Commands Frequency Sweep Commands See also Frequency Sweep starting on page 82 in chapter 3 Sweep Overview The following is an overview of the steps required to generate a sweep The commands
159. e other status registers Data that is waiting in the function generator s output buffer is immediately reported on the Message Available bit bit 4 Clearing an event register from one of the other register groups will clear the corresponding bits in the Status Byte condition register Reading all messages from the output buffer including any pending queries will clear the Message Available bit To set the enable register mask and generate an SRQ service request you must write a decimal value to the register using the SRE command Bit Definitions Status Byte Register Decimal Bit Number Value Definition 0 Not Used 1 Not Used Returns 0 1 Not Used 2 Not Used Returns 0 2 Error Queue 4 One or more errors are stored in the Error Queue 3 Questionable Data 8 One or more bits are set in the Questionable Data Register bits must be enabled 4 Message Available 16 Data is available in the instrument s output buffer 5 Standard Event 32 One or more bits are set in the Standard Event Register bits must be enabled 6 Master Summary 64 One or more bits are set in the Status Byte Register bits must be enabled 7 Not Used 128 Not Used Returns 0 227 Chapter 4 Remote Interface Reference The SCPI Status System The Status Byte condition register is cleared when e You execute the CLS clear status command e You read the event register from one of the other re
160. e register the waveform output frequency changes phase continuously following the next clock cycle The PIR determines how fast the phase value changes with time and ultimately controls the frequency being synthesized More bits in the phase accumulator result in finer frequency resolution Since the PIR affects only the rate of change of the phase value and not the phase itself changes in waveform frequency are phase continuous 296 Chapter 7 Tutorial Direct Digital Synthesis Phase Increment Register PIR f 64 Bits Pa _ 200 MHz Y MSBs 64 Bits 64 Bits 140r 16 bits Waveform Memory Address p Phase Register Phase Accumulator Circuitry The 33250A uses a 64 bit phase accumulator which yields 284 x 200 MHz or 10 8 picohertz frequency resolution internally Note that only the 14 or 16 most significant bits of the Phase Register are used to address waveform memory Therefore when synthesizing low frequencies less than 12 21 kHz the address will not change during every clock cycle However at higher frequencies greater than 12 2 kHz the address will change by more than one location during each clock cycle and some points will be skipped If too many points are skipped a phenomenon known as aliasing will occur and the waveform output will become somewhat distorted The Nyquist Sampling Theorem states that in order to prevent aliasing the highest frequency component
161. e time of ship ment Agilent further certifies that its calibration measure ments are traceable to the United States National Insti tute of Standards and Technology formerly National Bureau of Standards to the extent allowed by that organi zation s calibration facility and to the calibration facilities of other International Standards Organization members Warranty This Agilent product is warranted against defects in materials and workmanship for a period of three years from date of shipment Duration and conditions of warranty for this product may be superceded when the product is integrated into becomes a part of other Agilent products During the warranty period Agilent will at its option either repair or replace products which prove to be defective Warranty Service For warranty service or repair this product must be returned to a service facility designated by Agilent For products returned to Agilent for warranty service the Buyer shall prepay ship ping charges to Agilent and Agilent shall pay shipping charges to return the product to the Buyer However the Buyer shall pay all shipping charges duties and taxes for products returned to Agilent from another country Limitation of Warranty The foregoing warranty shall not apply to defects resulting from improper or inadequate maintenance by the Buyer Buyer supplied products or interfacing unauthorized mod ification or misuse operatio
162. eared No Change Off Factory Setting Internal Immediate Factory Setting 10 GPIB IEEE 488 e 57 600 Baud None 8 data bits DTR DSR Factory Setting Secured Parameters marked with a bullet are stored in non volatile memory For your convenience this table is duplicated on the rear cover of this manual and on the Quick Reference Card 127 128 Remote Interface Reference Remote Interface Reference e SCPI Command Summary on page 131 scr e Simplified Programming Overview on page 142 e Using the APPLy Command on page 144 e Output Configuration Commands on page 153 e Pulse Configuration Commands on page 166 e Amplitude Modulation AM Commands on page 169 e Frequency Modulation FM Commands on page 172 e Frequency Shift Keying FSK Commands on page 176 e Frequency Sweep Commands on page 179 e Burst Mode Commands on page 187 e Triggering Commands on page 195 e Arbitrary Waveform Commands on page 198 e State Storage Commands on page 209 e System Related Commands on page 213 e Interface Configuration Commands on page 218 e RS 232 Interface Configuration on page 219 e Phase Lock Commands on page 223 e The SCPI Status System on page 225 e Status Reporting Commands on page 235 e Calibration Commands on page 239 e An Introduction to the SCPI Language on page 241 e Using Device Clear on page 246 familiar with the language before attempting to pr
163. ed on the function generator s front panel will double to 20 Vpp and no error will be generated If you change from high impedance to 50 ohms the displayed amplitude will drop in half See the OUTP LOAD command on page 163 for more information You can set the output amplitude in Vpp Vrms or dBm by specifying the units as part of the APPLy command as shown below APPL SIN 5 0E 3 3 0 VRMS 2 5 Or you can use the VOLT UNIT command see page 165 to specify the output units for all commands that follow Unless you specify the units as part of the APPLy command the VOLT UNIT command takes precedence For example if you select Vrms using the VOLT UNIT command and do not include units with the APPLy command the value specified for the amplitude parameter in the APPLy command will be in Vrms 146 Chapter 4 Remote Interface Reference Using the APPLy Command You cannot specify the output amplitude in dBm if the output termination is currently set to high impedance The units are automatically converted to Vpp See the VOLT UNIT command on page 165 for more information Limits Due to Units Selection In some cases the amplitude limits are determined by the output units selected This may occur when the units are Vrms or dBm due to the differences in crest factor for the various output functions For example if you output a 5 Vrms square wave into 50 ohms and then change to the sine wave function
164. ed to 1 MHz for ramps and 25 MHz for arbitrary waveforms The default is 550 Hz e Frequency span 0 Hz to 80 MHz limited to 1 MHz for ramps and 25 MHz for arbitrary waveforms The default is 900 Hz e To sweep up in frequency set a positive frequency span To sweep down in frequency set a negative frequency span e For sweeps with Marker Off the Sync signal is a square waveform with a 50 duty cycle The Sync signal is a TTL high at the beginning of the sweep and goes low at the midpoint of the sweep The frequency of the sync waveform is equal to the specified sweep time The signal is output from the front panel Sync connector e For sweeps with Marker On the Sync signal is a TTL high at the beginning of the sweep and goes low at the marker frequency The signal is output from the front panel Sync connector e Front Panel Operation After enabling sweeps press the Start or Stop softkey again to toggle to the Center or Span softkey Then use the knob or numeric keypad to enter the desired values e Remote Interface Operation FREQuency CENTer lt frequency gt MINimum MAXimum FREQuency SPAN lt frequency gt MINimum MAXimum 84 Sweep Mode Chapter 3 Features and Functions Frequency Sweep You can sweep with either linear or logarithmic spacing For a linear sweep the function generator varies the output frequency in a linear fashion during the sweep For a logarithmic sweep the f
165. eform This section gives an example which shows you how to create and store an arbitrary waveform from the front panel To download an arbitrary waveform from the remote interface see Arbitrary Waveform Commands starting on page 198 For this example you will create and store the ramp waveform shown below using four waveform points Volt Div 1 Volt Time Div 1 ms 2 message is displayed indicating which waveform is currently selected Start the arbitrary waveform editor Press the Create New softkey to start the waveform editor While in the waveform editor you define the waveform by specifying time and voltage values for each point in the waveform When creating a new waveform the previous waveform in volatile memory is overwritten 103 Chapter 3 Features and Functions Arbitrary Waveforms Set the waveform period Press the Cycle Period softkey to set the time boundaries for the waveform The time value of the last point that can be defined in the waveform must be less than the specified cycle period For this example set the period of the waveform to 10 ms 1 000 000 0ms J Cycle j High Lowy Interp Init Edit Period Limit Limit Off Points Points Set the waveform voltage limits Press the High V Limit and Low V Limit softkeys to set the upper and lower voltage levels that can be reached while editing the waveform The upper limit must be greater than the lower limit By
166. eform in volatile memory and no error will be generated Use the DATA COPY command to copy the waveform to non volatile memory e Up to four user defined waveforms can be stored in non volatile memory Use the DATA DEL command to delete the waveform in volatile memory or any of the four user defined waveforms in non volatile memory Use the DATA CAT command to list all waveforms currently stored in volatile and non volatile memory as well as the five built in waveforms e After downloading the waveform data to memory use the FUNC USER command to choose the active waveform and the FUNC USER command to output it e The following statement shows how to use the DATA command to download seven points to volatile memory DATA VOLATILE 1 67 33 0 TEEN SO T 1 200 Chapter 4 Remote Interface Reference Arbitrary Waveform Commands DATA DAC VOLATILE lt binary block gt lt value gt lt value gt Download binary or decimal integer values from 2047 to 2047 into volatile memory You can download from 1 to 65 536 64K points per waveform in IEEE 488 2 binary block format or as a list of values The range of values corresponds to the values available using internal 12 bit DAC Digital to Analog Converter codes The function generator takes the specified number of points and expands them to fill waveform memory If you download less than 16 384 16K points a waveform with 16 384 points is automatica
167. ement Enter error string response Selecting a Trigger Source When Sweep or Burst is enabled the function generator will accept an immediate internal trigger a hardware trigger from the rear panel Trig In connector a manual trigger from the front panel key ora software bus trigger By default the internal trigger source is selected If you want to use an external or a software trigger source you must first select that source For example the following command strings sent from your computer will output a 3 cycle burst each time the rear panel Trig In connector receives the rising edge of a TTL pulse BURS NCYC 3 Set burst count to 3 cycles TRIG SLOP POS Set polarity to rising edge TRIG SOUR EXT Select external trigger source BURS STAT ON Enable burst mode 143 Chapter 4 Remote Interface Reference Using the APPLy Command Using the APPLy Command See also Output Configuration starting on page 49 in chapter 3 The APPLy command provides the most straightforward method to program the function generator over the remote interface You can select the function frequency amplitude and offset all in one command as shown in the syntax statement below APPLy lt function gt lt frequency gt lt amplitude gt lt offset gt For example the following command string sent from your computer will output a 3 Vpp sine wave at 5 kHz with a 2 5 volt offset APPL SIN 5 KHZ 3 0 VPP 2 5 V The APPLy
168. empt to set the marker frequency to a frequency not in this range the function generator will automatically set the marker frequency equal to the start frequency or stop frequency whichever is closer e The Sync signal setting is overridden by the setting of the Marker frequency used with the sweep mode see page 62 Therefore when the marker frequency is enabled and the sweep mode is also enabled the Sync signal setting is ignored e Front Panel Operation After enabling sweeps press the Marker softkey Then use the knob or numeric keypad to enter the desired marker frequency e Remote Interface Operation MARKer FREQuency lt frequency gt MINimum MAXimum 86 Chapter 3 Features and Functions Frequency Sweep Sweep Trigger Source In the sweep mode the function generator outputs a single sweep when a trigger signal is received After one sweep from the start frequency to the stop frequency the function generator waits for the next trigger while outputting the start frequency Sweep trigger source Internal External or Manual The default is Internal When the Internal immediate source is selected the function generator outputs a continuous sweep at a rate determined by the sweep time specified When the External source is selected the function generator will accept a hardware trigger applied to the rear panel Trig In connector The function generator initiates one sweep each time Trig In receives a
169. en volt 1 volt offset 0 1Vpp and OV offset 060 OUTPUT Fgen func square dcycle 20 20 duty cycle 070 OUTPUT Fgen trig sour bus Bus triggering 080 OUTPUT Fgen burst ncycles 3 l 090 OUTPUT Fgen burst state on Enable Burst 00 OUTPUT Fgen output state on Turn ON Output BNC 10 OUTPUT Fgen output sync on Enable Sync BNC 20 Check_errors 30 FOR I 1 TO 20 40 OUTPUT Fgen trg Send BUS trigger 50 WAIT 1 Wait 100msec 60 NEXT 70 PAUSE so 90 PRINT Download 20 point Arbitrary waveform 200 4 210 REAL Arb_20 1 20 220 DATA k h Akr 20 op lp lel ely a hel lel 230 READ Arb_20 240 OUTPUT Fgen data volatile Arb_20 250 OUTPUT Fgen func user volatile 260 OUTPUT Fgen apply user 10e3 1 0 270 Check_errors r 280 PAUSE 290r ot 300 PRINT Download 6 point Arbitrary waveform using Binary press CONTinue 310 320 INTEGER Arb_6 1 6 l 330 DATA 2047 2047 2047 2047 2047 2047 340 READ Arb_6 l 350 OUTPUT Fgen data dac volatile 212 360 Note that the WAIT commands are not needed for GPIB only for RS 232 370 WAIT 1 380 OUTPUT Bin Arb_6 l 390 WAIT 1 l 400 OUTPUT Fgen apply user 5000 1 0 Terminator APPLy 410 Check_errors 420 PAUSE 430 Continued 280 440 450 460 470 480 490 500 510 520 530 540 550 560 570 580 590 600 610 620 630 640 650 660 670 680 690 700 710 720 730 740 750 760 770 780 790 800 810 820 830
170. ence The SCPI Status System The Questionable Data event register is cleared when e You execute the CLS clear status command e You query the event register using the STAT QUES EVEN command The Questionable Data enable register is cleared when e You turn on the power the PSC command does not apply e You execute the STAT PRES command e You execute the STAT QUES ENAB 0 command 232 Chapter 4 Remote Interface Reference The SCPI Status System The Standard Event Register The Standard Event register group reports the following types of events power on detected command syntax errors command execution errors self test or calibration errors query errors or the OPC command has been executed Any or all of these conditions can be reported to the Standard Event summary bit through the enable register To set the enable register mask you must write a decimal value to the register using the ESE command Bit Definitions Standard Event Register Decimal Bit Number Value Definition 0 Operation Complete 1 All commands prior to and including OPC have completed and the overlapped command e g RG for burst has completed 1 Not Used 2 Not Used Returns 0 2 Query Error 4 The instrument tried to read the output buffer but it was empty Or a new command line was received before a previous query has been read Or both the input and output
171. ency of the waveform is equal to the specified sweep time When the External trigger source is selected the function generator automatically disables the trigger out signal The Trig Out connector cannot be used for both operations at the same time an externally triggered waveform uses the same connector to trigger the sweep When the Manual trigger source is selected the function generator outputs a pulse gt 1 ps pulse width from the Trig Out connector at the beginning of each sweep or burst Front Panel Operation After enabling sweeps press the Trigger Setup softkey Then select the desired edge by pressing the Trig Out softkey Remote Interface Operation OUTPut TRIGger SLOPe POSitive NEGative OUTPut TRIGger OFF ON 88 Chapter 3 Features and Functions Burst Mode Burst Mode You can configure the function generator to output a waveform with a specified number of cycles called a burst The function generator can produce a burst using sine square ramp pulse or arbitrary waveforms noise is allowed only in the gated burst mode and dc is not allowed For more information on the fundamentals of the burst mode refer to chapter 7 Tutorial To Select Burst e The function generator will not allow burst to be enabled at the same time that sweep or any modulation mode is enabled When you enable burst the sweep or modulation mode is turned off e Front Panel Operation You must enable burst
172. ending a bus trigger command The function generator initiates one sweep or outputs one burst each time a bus trigger command is received e To select the bus trigger source send the following command TRIGger SOURce BUS e To trigger the function generator from the remote interface GPIB or RS 232 when the Bus source selected send the TRIG or TRG trigger command The front panel key is illuminated when the function generator is waiting for a bus trigger 100 Chapter 3 Features and Functions Triggering Trigger Input Signal This rear panel connector is used in the following modes Trig In Out INPUT FSK Burst 45V gt gt 100ns ry OV Rising edge shown Triggered Sweep Mode To select the external source press the Trigger Setup softkey and then select the Source Ext softkey or execute the TRIG SOUR EXT command from the remote interface sweep must be enabled When the rising or falling edge you specify which edge of a TTL pulse is received on the Trig In connector the function generator outputs a single sweep Externally Modulated FSK Mode To enable the externally modulated mode press the Source softkey from the front panel or execute the FSK SOUR EXT command from the remote interface FSK must be enabled When a logic low level is present the carrier frequency is output When a logic high level is present the hop frequency is output The maximum external FSK rate is 1 MHz Tri
173. enerator is to become acquainted with the front panel We have written the exercises in this chapter to prepare the instrument for use and help you get familiar with some of its front panel operations This chapter is divided into the following sections e To Prepare the Function Generator for Use on page 15 e To Adjust the Carrying Handle on page 16 e To Set the Output Frequency on page 17 e To Set the Output Amplitude on page 18 e To Set a DC Offset Voltage on page 20 e To Set the Duty Cycle on page 21 e To Configure a Pulse Waveform on page 22 e To View a Waveform Graph on page 23 e To Output a Stored Arbitrary Waveform on page 24 e To Use the Built In Help System on page 25 e To Rack Mount the Function Generator on page 27 14 Power Switch 1 2 Chapter 1 Quick Start To Prepare the Function Generator for Use To Prepare the Function Generator for Use Check the list of supplied items Verify that you have received the following items with your instrument If anything is missing please contact your nearest Agilent Sales Office Q One power cord This User s Guide One Service Guide One folded Quick Reference Guide Certificate of Calibration Connectivity software on CD ROM One RS 232 cable Oocvovovo vO Connect the power cord and turn on the function generator Several power on information messages are displayed after the function generator performs its power on self test
174. enerator uses the current units selection for both front panel and remote interface operations For example if you select VRMS from the remote interface using the VOLT UNIT command the units are displayed as VRMS on the front panel e The VOLT query command see page 156 returns the output amplitude in the units set by the most recent VOLT UNIT command e The output units for amplitude cannot be set to dBm if the output termination is currently set to high impedance The units are automatically converted to Vpp See the OUTP LOAD command on page 163 for more information e Unless you specify the units as part of the APPLy or VOLT command the VOLT UNIT command takes precedence For example if you select Vrms using the VOLT UNIT command and do not include units with the APPLy or VOLT command the value specified for the amplitude parameter in the APPLy command will be in Vrms 165 Chapter 4 Remote Interface Reference Pulse Configuration Commands Pulse Configuration Commands See also Pulse Waveforms starting on page 64 in chapter 3 This section describes the low level commands used to program the function generator to output a pulse waveform To select the pulse function use the FUNC PULS command see page 153 Refer to the diagram below for the command descriptions that follow 90 90 50 50 a Pulse Width E 10 10 lt o Rise Time Fall Time Period
175. enu The calibration message is listed as one of the messages on the display e Remote Interface Operation To store the calibration message send the following command CAL STR Cal Due 01 June 2001 126 Note The power on state will be different if you have enabled the power down recall mode See Instrument State Storage on page 109 Chapter 3 Features and Functions Factory Default Settings Factory Default Settings Output Configuration Function Frequency Amplitude Offset Output Units Output Termination Autorange Carrier Waveform Modulating Waveform AM Depth FM Deviation FSK Hop Frequency FSK Rate Modulation State Sweep Start Stop Frequency Sweep Time Sweep Mode Sweep State Burst Burst Frequency Burst Count Burst Period Burst Starting Phase Burst State Power Down Recall Display Mode Error Queue Output State Triggering Operations Trigger Source GPIB Address Interface Baud Rate Parity Handshake Calibration Calibration State Modulation AM FM FSK System Related Operations Stored States Stored Arbs Remote Inteface Configuration Factory Setting Sine wave 1 kHz 100 mVpp 0 000 Vdc Vpp 50Q On Factory Setting 1 kHz Sine wave 100 Hz Sine wave 100 100 Hz 100 Hz 10 Hz Off Factory Setting 100 Hz 1 kHz 1 Second Linear Off Factory Setting 1 kHz 1 Cycle 10 ms 0 Off Factory Setting e Disabled On Errors are Cl
176. equation 1 x 10 Phase Noise in dBc 20 Jitter in Seconds rms _ 2n x Frequency Quantization Errors Finite DAC resolution 12 bits leads to voltage quantization errors Assuming the errors are uniformly distributed over a range of 0 5 least significant bit LSB the equivalent noise level is 74 dBc for a sine wave that uses the full DAC range 4 096 levels Similarly finite length waveform memory leads to phase quantization errors Treating these errors as low level phase modulation and assuming a uniform distribution over a range of 0 5 LSB the equivalent noise level is 76 dBc for a sine wave that is 16K samples long All of the 33250 s standard waveforms use the entire DAC range and are 16K samples in length Any arbitrary waveforms that use less than the entire DAC range or that are specified with fewer than 16 384 points will exhibit proportionally higher relative quantization errors 303 Chapter 7 Tutorial Output Amplitude Control Output Amplitude Control The 33250A uses an analog multiplier to control the signal amplitude over a 10 dB range As shown below one of the multiplier s inputs is routed from the output of an anti aliasing filter The other input is routed from a dc control voltage which is the sum of the outputs from two DACs One of the DACs is set to a nominal voltage corresponding to the desired output amplitude The second DAC provides a voltage to correct for frequency respon
177. er from the fundamental frequency and its harmonics is transferred to the spectral components of the rectangular sampling function You can reduce leakage errors by adjusting the window length to include an integer number of cycles or by including more cycles within the window to reduce the residual end point discontinuity size Some signals are composed of discrete non harmonically related frequencies Since these signals are non repetitive all frequency components cannot be harmonically related to the window length You should be careful in these situations to minimize end point discontinuities and spectral leakage 0 90 180 270 360 0 90 180 270 360 1 Cycle Arbitrary Waveform with Discontinuity 400 600 700 00 80 D0 KHz kHz kHz kHz kHz kHz Spectrum of Above Waveform at 100 kHz 299 Chapter 7 Tutorial Square Waveform Generation Square Waveform Generation To eliminate distortion due to aliasing at higher frequencies the 33250A uses a different waveform generation technique to create square waves For frequencies above 2 MHz square waveforms are created by routing a DDS generated sine wave into a comparator The digital output from the comparator is then used as the basis for the square wave output The duty cycle of the waveform can be varied by changing the comparator s threshold For frequencies below 2 MHz different waveshapes are loaded into waveform memory to m
178. er source e Specify the slope rising or falling edge of the Trig Out signal 31 Chapter 2 Front Panel Menu Operation Front Panel Menu Reference Store and recall instrument states e Store up to four instrument states in non volatile memory e Assign a custom name to each storage location e Recall stored instrument states e Restore all instrument settings to their factory default values e Select the instrument s power on configuration last or factory default Configure system related parameters e Generate a dc only voltage level e Enable disable the Sync signal which is output from the Sync connector e Select the output termination 1Q to 10 KQ or Infinite e Enable disable amplitude autoranging Select the waveform polarity normal or inverted e Select the GPIB address e Configure the RS 232 interface baud rate parity and handshake mode Select how periods and commas are used in numbers displayed on the front panel e Select the local language for front panel messages and help text e Enable disable the tone heard when an error is generated e Enable disable the display bulb saver mode e Adjust the contrast setting of the front panel display e Perform an instrument self test e Secure unsecure the instrument for calibration and perform manual calibrations e Query the instrument s firmware revision codes View the list of Help topics
179. eral low level registers called Condition registers Event registers and Enable registers which control the action of specific bits within the register group What is a Condition Register A condition register continuously monitors the state of the instrument The bits in the condition register are updated in real time and the bits are not latched or buffered This is a read only register and bits are not cleared when you read the register A query of a condition register returns a decimal value which corresponds to the binary weighted sum of all bits set in that register What is an Event Register An event register latches the various events from changes in the condition register There is no buffering in this register while an event bit is set subsequent events corresponding to that bit are ignored This is a read only register Once a bit is set it remains set until cleared by query command such as STAT QUES EVEN or a CLS clear status command A query of this register returns a decimal value which corresponds to the binary weighted sum of all bits set in that register What is an Enable Register An enable register defines which bits in the event register will be reported to the Status Byte register group You can write to or read from an enable register A CLS clear status command will not clear the enable register but it does clear all bits in the event register A STAT PRES command clears all bits in t
180. eration methods The 33250A uses a signal generation technique called Direct Digital Synthesis DDS for all waveform functions except pulse As shown below a stream of digital data representing the desired waveform is sequentially read from waveform memory and is applied to the input of a digital to analog converter DAC The DAC is clocked at the function generator s sampling frequency of 200 MHz and outputs a series of voltage steps approximating the desired waveform A low pass anti aliasing filter then smooths the voltage steps to create the final waveform Waveform nn Memory S Anti Aliasing 200 MHz 3 Filter Waveform DAC Direct Digital Synthesis Circuitry The 33250A uses two anti aliasing filters A ninth order elliptical filter is used for continuous sine waves because of its nearly flat passband and sharp cutoff above 80 MHz Since elliptical filters exhibit severe ringing for waveforms other than continuous sine waves a seventh order linear phase filter is used for all other waveforms functions For standard waveforms and arbitrary waveforms that are defined with fewer than 16 384 16K points the function generator uses waveform memory that is 16K words deep For arbitrary waveforms that are defined with more than 16K points the function generator uses waveform memory that is 65 536 64K words deep 295 Chapter 7 Tutorial Direct Digital Synthesis The 33250A repre
181. ery command or the OPC operation complete command to signal when the sweep or burst is complete The OPC command returns 1 to the output buffer when the sweep or burst is complete The OPC command sets the Operation Complete bit bit 0 in the Standard Event register when the sweep or burst is complete TRIGger Trigger a sweep or burst from the remote interface This command can be used with any of the available trigger sources TRIG SOUR command For example you can use the TRIG command to issue an immediate trigger while waiting for an external trigger TRG Trigger a sweep or burst from the remote interface only if the bus software trigger source is currently selected TRIG SOUR BUS command TRIGger DELay lt seconds gt MINimum MAXimum TRIGger DELay MINimum MAXimum Insert a time delay between the receipt of the trigger and the start of the burst waveform used in triggered burst mode only Select from 0 seconds to 85 seconds The default delay is 0 MIN 0 seconds MAX 85 seconds The DEL query returns the trigger delay in seconds TRIGger SLOPe POSitive NEGative TRIGger SLOPe Select whether the function generator uses the rising edge or falling edge of the trigger signal on the rear panel Trig In connector The default is POS rising edge The SLOP query returns POS or NEG 196 Chapter 4 Remote Interface Reference Triggering Commands BURSt GATE POLarity NO
182. ete calibration may increase the value by many counts e Front Panel Operation Press Utility and then select the Cal Info softkey from the Test Cal menu The calibration count is listed as one of the messages on the display e Remote Interface Operation CALibration COUNt 125 Chapter 3 Features and Functions Calibration Overview Calibration Message The function generator allows you to store one message in calibration memory in the mainframe For example you can store such information as the date when the last calibration was performed the date when the next calibration is due the function generator s serial number or the name and phone number of the person to contact for a new calibration e You can record a calibration message only from the remote interface and only when the function generator is unsecured You can read the message from either the front panel or over the remote interface You can read the calibration message whether the function generator is secured or unsecured e The calibration message may contain up to 40 characters additional characters are truncated e Storing a calibration message will overwrite any message previously stored in memory e The calibration message is stored in non volatile memory and does not change when power has been off or after a remote interface reset e Front Panel Operation Press Vii and then select the Cal Info softkey from the Test Cal m
183. etting This feature is available from the front panel only Display contrast 0 to 100 The default is 50 The contrast setting is stored in non volatile memory and does not change when power has been off or after a remote interface reset Front Panel Operation Press wiility softkey from the System menu and then select the Display Contr Self Test A power on self test occurs automatically when you turn on the function generator This limited test assures you that the function generator is operational A complete self test runs a series of tests and takes approximately 15 seconds to execute If all tests pass you can have high confidence that the function generator is fully operational If the complete self test is successful Self Test Passed is displayed on the front panel If the self test fails Self Test Failed is displayed and an error number is shown See the Agilent 33250A Service Guide for instructions on returning the instrument to Agilent for service Front Panel Operation Press vitity and then select the Self Test softkey from the Test Cal menu Remote Interface Operation TST Returns 0 if the self test passes or 1 if it fails If the self test fails an error message is also generated with additional information on why the test failed 114 Chapter 3 Features and Functions System Related Operations Display Control For security reasons or to speed up the
184. fied arb waveform does not exist error is generated DATA ATTRibute PTPeak lt arb name gt Query the peak to peak value of all data points for the specified arbitrary waveform The default arb name is the arbitrary waveform currently active selected with FUNC USER command e This command returns a value from 0 to 1 0 with 1 0 indicating full amplitude available e The maximum amplitude will be limited if the data points do not span the full range of the output DAC Digital to Analog Converter For example the built in Sinc waveform does not use the full range of binary values between 1 and therefore its maximum amplitude is 6 087 Vpp into 50 ohms e Ifyou query a waveform that is not currently stored in memory a Specified arb waveform does not exist error is generated 208 Chapter 4 Remote Interface Reference State Storage Commands State Storage Commands The function generator has five storage locations in non volatile memory to store instrument states The locations are numbered 0 through 4 The function generator automatically uses location 0 to hold the state of the instrument at power down You can also assign a user defined name to each of the locations 1 through 4 for use from the front panel SAV 0 1 2 3 4 Store save the current instrument state in the specified non volatile storage location Any state previously stored in the same location will be
185. fifth instrument state you cannot store to this location from the front panel However note that location 0 is automatically overwritten when power is cycled the instrument state previously stored will be overwritten e The state storage feature remembers the selected function including arbitrary waveforms frequency amplitude dc offset duty cycle symmetry as well as any modulation parameters in use e When shipped from the factory storage locations 1 through 4 are empty location 0 contains the power down state e When power is turned off the function generator automatically stores its state in storage location 0 You can configure the function generator to automatically recall the power down state when power is restored However when shipped from the factory the function generator is configured to automatically recall the factory default state at power on 109 Chapter 3 Features and Functions System Related Operations e You can assign a custom name to each of the storage locations however you cannot name location 0 from the front panel You can name a location from the front panel or over the remote interface but you can only recall a state by name from the front panel From the remote interface you can only recall a stored state using a number 0 through 4 e The name can contain up to 12 characters The first character must be a letter A Z but the remaining charac
186. finite using the BURS NCYC command Used in the triggered burst mode only Set the burst period Set the burst period the interval at which internally triggered bursts are generated to any value from 1 ps to 500 seconds using the BURS INT PER command Used only in the triggered burst mode with an internal trigger source Set the burst starting phase Set the starting phase of the burst to any value from 360 degrees to 360 degrees using the BURS PHAS command Select the trigger source Select the trigger source using the TRIG SOUR command Used in the triggered burst mode only Enable the burst mode After you have set up the other burst parameters use the BURS STAT ON command to enable the burst mode 188 Chapter 4 Remote Interface Reference Burst Mode Commands Burst Mode Commands Use the APPLy command or the equivalent FUNC FREQ VOLT and VOLT OFFS commands to configure the waveform For internally triggered bursts the minimum frequency is 2 mHz For sine and square waveforms frequencies above 25 MHz are allowed only with an infinite burst count BURSt MODE TRIGgered GATed BURSt MODE Select the burst mode In the triggered mode the function generator outputs a waveform with a specified number of cycles burst count each time a trigger is received from the specified trigger source TRIG SOUR command In the gated mode the output waveform is either on or off based
187. function generator and a modem When the RS 232 interface is selected the function generator sets the DTR line true The DSR line is set true when the modem is on line The function generator sets the RTS line true when it is ready to receive data The modem sets the CTS line true when it is ready to accept data The function generator sets the RTS line false when the input buffer is almost full about 100 characters and releases the line when space is available again e RTS CTS This mode operates the same as the DTR DSR mode but uses the RTS request to send and CTS clear to send lines on the RS 232 connector instead When the CTS line goes true the function generator sends data over the interface When the line goes false the function generator stops sending information typically within six characters The function generator sets the RTS line false when the input buffer is almost full about 100 characters and releases the line when space is available again e XON XOFF This mode uses special characters embedded in the data stream to control the flow If the function generator is addressed to send data it continues sending data until the XOFF character 13H is received When the XON character 11H is received the function generator resumes sending data 220 Chapter 4 Remote Interface Reference RS 232 Interface Configuration RS 232 Data Frame Format A character frame consists of all the transmitted bits th
188. g variable with at least 50 characters Agilent Technologies 33250A 0 m mm L Il f ff gg p m mm Main firmware revision number LII Loader firmware revision number f ff TO processor firmware revision number gg Gate array revision number p Printed circuit board revision number DISPlay OFF ON DISPlay Disable or enable the function generator front panel display When it is disabled the front panel display is blanked however the bulb used to backlight the display remains enabled The DISP query returns 0 OFF or 1 ON e With the front panel display disabled there will be some improvement in command execution speed from the remote interface e Sending a message to the front panel display from the remote interface DISP TEXT command overrides the display state This means that you can display a message even if the display is disabled remote interface errors are always displayed even if the display is disabled e The display is automatically enabled when power is cycled after an instrument reset RST command or when you return to local front panel operation Press the key or execute the IEEE 488 GTL Go To Local command from the remote interface to return to the local state e The display state is saved when you store the instrument state using SAV command When you recall the instrument state using RCL command the front panel display will return to the previous state 214 Chapter
189. ggered Burst Mode To select the external source press the Trigger Setup softkey and then select the Source Ext softkey or execute the TRIG SOUR EXT command from the remote interface burst must be enabled The function generator outputs a waveform with a specified number of cycles burst count each time a trigger is received from the specified trigger source External Gated Burst Mode To enable the gated mode press the Gated softkey or execute the BURS MODE GAT command from the remote interface burst must be enabled When the external gate signal is true the function generator outputs a continuous waveform When the external gate signal goes false the current waveform cycle is completed and then the function generator stops while remaining at the voltage level corresponding to the starting burst phase For noise the output stops immediately when the gate signal goes false 101 Chapter 3 Features and Functions Triggering Trigger Output Signal A trigger out signal is provided on the rear panel Trig Out connector used with sweep and burst only When enabled a TTL compatible square waveform with either a rising edge default or falling edge is output from the rear panel Trig Out connector at the beginning of the sweep or burst Trig In Out OUTPUT FSK Burst 45V gt gt 1 us lt lt OV Rising edge shown e When the Internal immediate trigger source is selected the function generator
190. gister groups only the corresponding bits are cleared in the condition register The Status Byte enable register is cleared when e You execute the SRE 0 command e You turn the power on and have previously configured the function generator to clear the enable register using the PSC 1 command Note that the enable register will not be cleared at power on if you have configured the function generator using the PSC 0 command 228 Chapter 4 Remote Interface Reference The SCPI Status System Using Service Request SRQ and Serial Poll You must configure your computer to respond to the IEEE 488 service request SRQ interrupt to use this capability Use the Status Byte enable register SRE command to select which condition bits will assert the IEEE 488 SRQ line If bit 6 RQS transitions from a 0 to a 1 then an IEEE 488 service request message is sent to your computer The computer may then poll the instruments on the interface bus to identify which one is asserting the service request line that is the instrument with bit 6 set in its Serial Poll response When a Serial Poll is issued bit 6 RQS is cleared in the Serial Poll response no other bits are affected and the service request line is cleared The Master Summary Bit in the STB response is not cleared To obtain the Serial Poll response send an IEEE 488 Serial Poll message The instrument sends a one byte binary response Performi
191. grees The default is 0 degrees From the remote interface you can set the starting phase in degrees or radians using the UNIT ANGL command see page 192 From the front panel the starting phase is always displayed in degrees radians are not available If you set the starting phase in radians from the remote interface and then return to front panel operation you will see that the function generator converts the phase to degrees For sine square and ramp waveforms 0 degrees is the point at which the waveform crosses zero volts or the dc offset value in a positive going direction For arbitrary waveforms 0 degrees is the first waveform point downloaded to memory The burst phase has no effect on pulse or noise waveforms The burst phase is also used in the gated burst mode When the gate signal goes false the current waveform cycle is completed and then the function generator stops The output will remain at the voltage level corresponding to the starting burst phase Front Panel Operation To set the burst phase press the Start Phase softkey and then use the knob or numeric keypad to enter the desired phase in degrees Remote Interface Operation BURSt PHASe lt angle gt MINimum MAXimum 95 Chapter 3 Features and Functions Burst Mode Burst Trigger Source In the triggered burst mode the function generator outputs a burst with the specified number of cycles burst count each time a trigger is received Af
192. h lt seconds gt MINimum MAXimum 50 to 50 Thresholds WIDTh MINimum MAXimum TRANsition lt seconds gt MINimum MAXimum 10 to 90 Thresholds TRANsition MINimum MAXimum Modulation Commands see page 169 for more information AM INTernal FUNCtion SINusoid SQUare RAMP NRAMp TRIangle NOISe USER FUNCtion AM INTernal FREQuency lt frequency gt MINimum MAXimum FREQuency MINimum MAXimum AM DEPTh lt depth in percent gt MINimum MAXimum AM DEPTh MINimum MAXimum AM SOURce INTernal EXTernal AM SOURce AM STATe OFF ON AM STATe Parameters shown in bold are selected following a RST reset command 133 Chapter 4 Remote Interface Reference SCPI Command Summary FM Commands FM INTernal FUNCtion SINusoid SQUare RAMP NRAMp TRIangle NOISe USER FUNCtion FM INTernal FREQuency lt frequency gt MINimum MAXimum FREQuency MINimum MAXimum FM DEViation lt peak deviation in Hz gt MINimum MAXimum FM DEViation MINimum MAXimum M SOURce INTernal EXTernal M SOURce FM STATe OFF ON FM STATe FSK Commands FSKey FREQuency lt frequency gt MINimum MAXimum Key FREQuency INimum MAXimum S S FSKey INTernal RATE lt rate in Hz gt MINimum MAXimum FSKey INTernal RATE MINimum MAXimum S S Ss S Key SOURce INTernal EXTernal Key SOURcCe
193. he modulation For example a depth setting of 80 causes the amplitude to vary from 10 to 90 of the amplitude setting 90 10 80 with either an internal or a full scale 5V external modulating signal 310 Chapter 7 Tutorial Modulation Frequency Modulation FM For FM the DSP uses modulation samples to modify the output frequency of the instrument by changing the content of the PIR see Direct Digital Synthesis on page 295 Note that since the rear panel Modulation In connector is dc coupled you can use the 33250A to emulate a voltage controlled oscillator VCO The variation in frequency of the modulating waveform from the carrier frequency is called the frequency deviation Waveforms with frequency deviations less than 1 of the modulating signal s bandwidth are referred to as narrowband FM Waveforms with larger deviations are referred to as wideband FM The bandwidth of the modulated signal can be approximated by the following equations BW 2 x Modulating Signal Bandwidth For narrowband FM BW 2 x Deviation Modulating Signal Bandwidth For wideband FM In the United States commercial FM stations usually have a modulation bandwidth of 15 kHz and deviation of 75 kHz making them wideband Therefore the modulated bandwidth is 2 x 75 kHz 15 kHz 180 kHz Channel spacing is 200 kHz Modulating Signal HH a i i l i Modulated Carrier Frequency Modulation 311
194. he current waveform cycle is completed and then the function generator stops while remaining at the voltage level corresponding to the starting burst phase of the selected waveform For a noise waveform the output stops immediately when the gate signal goes false Burst Mode Burst Count Burst Period Burst Phase Trigger Source BURS MODE BURS NCYC BURS INT PER BURS PHAS TRIG SOUR Triggered Burst Mode Internal Trigger TRIGgered Available Available Available IMMediate Triggered Burst Mode F External Trigger TRIGgered Available Not Used Available EXTernal BUS Gated Burst Mode GATed Not Used Not Used Available Not Used External Trigger 90 Chapter 3 Features and Functions Burst Mode When the gated mode is selected the burst count burst period and trigger source are ignored these parameters are used for the triggered burst mode only If a manual trigger is received it is ignored and no error will be generated When the gated mode is selected you can also select the polarity of the signal on the rear panel Trig In connector Front Panel Operation After enabling bursts press the N Cycle triggered or Gated softkey To select the polarity of the external gate signal on the Trig In connector press the Polarity softkey The default polarity is POS true high logic Remote Interface Operation BURSt MODE TRIGgered GATed Use the following command to select the po
195. he enable register To enable bits in the enable register to be reported to the Status Byte register you must write a decimal value which corresponds to the binary weighted sum of the corresponding bits 225 Chapter 4 Remote Interface Reference The SCPI Status System Agilent 33250A Status System Questionable Data Register NOTES C Condition Register C EV EN EV Event Register o Volt Ovid o lt gt Jh EN Enable Register H 1 a Ovid Overload a Over Temp 3 ae 5 Loop Unlock 5 6 6 7 Ext Mod Ovid 7 8 Cal Error 8 External Ref 9 T a y t2 E 13 14 14 Jj AES 15 Error Queue STAT QUES COND STAT QUES EVENt A lt a n STAT QUES ENABLe lt value gt STAT QUES ENABLe r Status Byte Register SYST ERRor Output Buffer SN lt Serial Poll SRE lt value gt STB SRE __ Summary Bit RQS Standard Event Register EV Operation Complete 1 Query Error 2 Device Error 3 Execution Error 4 Command Error 5 X 6 Power On 7 I lt ESR ESE lt value gt ESE 226 Chapter 4 Remote Interface Reference The SCPI Status System The Status Byte Register The Status Byte summary register reports conditions from th
196. ictions below The default edge time is 5 ns e The specified edge time must fit within the specified pulse width as shown below The function generator will adjust the edge time as needed to accommodate the specified pulse width Edge Time lt 0 625 X Pulse Width e Front Panel Operation After selecting the pulse function press the Edge Time softkey Then use the knob or numeric keypad to enter the desired edge time e Remote Interface Operation PULSe TRANsition lt seconds gt MINimum MAXimum 66 Chapter 3 Features and Functions Amplitude Modulation AM Amplitude Modulation AM A modulated waveform consists of a carrier waveform and a modulating waveform In AM the amplitude of the carrier is varied by the instantaneous voltage of the modulating waveform The function generator will accept an internal or external modulation source For more information on the fundamentals of Amplitude Modulation refer to chapter 7 Tutorial To Select AM Modulation e The function generator will allow only one modulation mode to be enabled at a time For example you cannot enable AM and FM at the same time When you enable AM the previous modulation mode is turned off e The function generator will not allow AM to be enabled at the same time that sweep or burst is enabled When you enable AM the sweep or burst mode is turned off e Front Panel Operation You must enable AM before setting up any of the other
197. ified frequency amplitude and dc offset The waveform is output as soon as the command is executed e This command preserves the current pulse width setting PULS WIDT command and edge time setting PULS TRAN command However based on the specified frequency the function generator will adjust the pulse width or edge time to comply with the frequency restrictions for pulse waveforms See page 166 for more information on setting the pulse width and edge time e In most applications the repetition rate for pulse waveforms is specified using a waveform period rather than frequency The APPLy command will make approximations in some cases to generate a pulse with the specified frequency Therefore the recommended method for setting the repetition rate for pulse waveforms is using the PULS PER command see page 166 150 Chapter 4 Remote Interface Reference Using the APPLy Command APPLy NOISe lt frequency DEFault gt lt amplitude gt lt offset gt 1 Output Gaussian noise with the specified amplitude and dc offset The waveform is output as soon as the command is executed e The frequency parameter has no effect for this command but you must specify a value or DEF ault the noise function has a 50 MHz bandwidth If you specify a frequency it has no effect on the noise output but the value is remembered when you change to a different function The following statement shows the use of the APPLy command for
198. ignal The rear panel Trig connector cannot be used for both operations at the same time an externally triggered waveform uses the same connector to trigger the sweep or burst Settings conflict trigger output connector used by FSK If you have enabled FSK and have selected the external trigger source FSK SOUR EXT command the trigger out signal cannot be enabled OUTP TRIG ON command The rear panel Trig connector cannot be used for both operations at the same time 253 221 221 221 221 221 Chapter 5 Error Messages Execution Errors Settings conflict trigger output connector used by burst gate If you have selected the gated burst mode BURS MODE GAT command with burst enabled the trigger out signal cannot be enabled OUTP TRIG ON command The rear panel Trig connector cannot be used for both operations at the same time Settings conflict trigger output connector used by trigger external When the external trigger source is selected TRIG SOUR EXT command the function generator automatically disables the trigger out signal The rear panel Trig connector cannot be used for both operations at the same time Settings conflict frequency reduced for user function For arbitrary waveforms the output frequency is limited to 25 MHz When you change to the arbitrary waveform function APPL USER or FUNC USER command from a function that allows a higher frequency the f
199. igure a Pulse Waveform 22 To View a Waveform Graph 23 To Output a Stored Arbitrary Waveform 24 To Use the Built In Help System 25 To Rack Mount the Function Generator 27 Chapter 2 Front Panel Menu Operation Front Panel Menu Reference 31 To Select the Output Termination 33 To Reset the Function Generator 33 To Output a Modulated Waveform 34 To Output an FSK Waveform 36 To Output a Frequency Sweep 38 To Output a Burst Waveform 40 To Trigger a Sweep or Burst 42 To Store the Instrument State 43 To Configure the Remote Interface 44 U9 U05 Chapter 3 Features and Functions Output Configuration 49 Pulse Waveforms 64 Amplitude Modulation AM 67 Frequency Modulation FM 72 Frequency Shift Keying FSK Modulation 78 Frequency Sweep 82 Burst Mode 89 Triggering 98 Arbitrary Waveforms 103 System Related Operations 109 Remote Interface Configuration 118 Calibration Overview 123 Factory Default Settings 127 a c e O Contents Chapter 4 Remote Interface Reference SCPI Command Summary 131 Simplified Programming Overview 142 Using the APPLy Command 144 Output Configuration Commands 153 Pulse Configuration Commands 166 Amplitude Modulation AM Commands 169 Frequency Modulation FM Commands 172 Frequency Shift Keying FSK Commands 176 Frequency Sweep Commands 179 Burst Mode Commands 187 Triggering Commands 195 Arbitrary Waveform Commands 198 State Storage Commands 209
200. ile loop 5s enabled sets SRQ errors Request status byte Read status byte Test Master Summary bit Query instrument information Read result into IdStr Make that data the message on box Query any errors data Read Errnum Error String End if find 0 No Error amp ErrVal 1l Display errors Update the box Request error message Read error message 285 Chapter 6 Application Programs Example Microsoft Visual Basic for Windows Sub WaitForOPC Dim Stats As Byte With Arb Stats I10 Query STB Read Status Byte Do While Stats And 64 0 Test for Master Summary Bit Sleep 100 Pause for 100msec Stats 10 Query STB Read Status Byte Loop End With End Sub Sub Fill_array ByRef data_array As Double r Routine can be used to fill array passed from Main Program Fills entire array with sequence of 1 0 a 1 ata_array 0 ata_array 1 ata_array 2 ata_array 3 ata_array 4 ata_array 5 ata_array 6 ata_array 7 ata_array 8 ata_array 9 ata_array 10 ata_array 11 ata_array 12 3 4 5 6 7 8 9 Il IRR I ata_array l ata_array 1 ata_array 1 ata_array 1 ata_array 1 ata_array 1 ata_array 1 SHE E E HE Il PRP Woe a amp Pa Doe Ya Pa a O oe OS ee re G O End Sub 286 Chapter 6 Application Programs Example Microsoft Visual C for Windows Example Microsoft Visual C
201. inimize jitter Waveform Anti Aliasing DAC Filter Comparator Threshold Voltage DAC Square Waveform Generation Circuitry Pulse Waveform Generation To eliminate distortion due to aliasing at higher frequencies the 33250A also uses a different waveform generation technique to create pulse waves For pulse waveform generation clock cycles are counted to derive both the period and pulse width To achieve fine period resolution the clock frequency is varied from 100 MHz to 200 MHz by a phase locked loop see the following page To achieve fine period width resolution an analog delay 0 to 10 ns is applied to the trailing edge The rising and falling edge times are controlled by a circuit that varies the charging currents in a capacitor Period pulse width and edge time are controlled independently within certain limits 300 Chapter 7 Tutorial Pulse Waveform Generation Period Counter L di Ed Edge Time _ 100 200 MHz aoe Circuit gt e Set OI TY SN et Load Clear z 3 AT b Flip Flop a V Cv Width ae Counter Delay 7 L Toad 40 ne Trailing Edge wis Pulse Waveform Generation Circuitry 90 90 50 50 a Pulse Width ae 10 10 Rise Time Fall Time Period Pulse Waveform Parameters 301 Chapter 7 Tutorial Signal Imperfections Signal Imperfections For sine waveforms signal imperfections are easie
202. ion printf AM Modulation n TO00bj gt Output OUTPut LOAD INFinity I00bj gt Output APPLy SINusoid 1le6 1 0 TOOb4j gt Output AM INTernal FUNCtion RAMP TOObj gt Output AM INTernal FREQuency 10e3 vas TOOb3j gt Output AM DEPTh 80 I00bj gt Output AM STATe ON Check_Errors I00b Pause IOO0bj gt Output am stat off FM Modulation printf FM Modulation n TOOb3j gt Output outp load 50 TOObj gt Output appl sin 20e3 1 0 I00bj gt Output fm dev 20e3 TOObj gt Output fm int freq 1000 TO00bj gt Output fm stat on Check_Errors I00b Pause I00bj gt Output fm stat off LA Continued 289 Chapter 6 Application Programs Example Microsoft Visual C for Windows 1 second sweep time Start frequency 100Hz Stop frequency 20kHz Turn ON sweeping Routine check for errors Turn OFF sweeping Disable Output BNC Low OV High 0 75V lms intervals 100us pulse width Edge time 10us Select Function Pulse Enable Output BNC Vary edge by lusec steps Wait 300msec Routine check for errors Turn OFF Output BNC Disable Sync BNC Select square wave 20kHz 1Vpp and OV offset 20 duty cycle Bus triggering Burst of 3 cycles Enable Burst Turn On Output BNC Enable Sync BNC Routine check for errors Send BUS trigger Wait 100msec Linear Sweep printf Line
203. istance in order to make the calculation dBm 10 x logy P 0 001 where P Vgus Ry For a sine wave into a 50Q load the following table relates dBm to voltage dBm RMS Voltage Peak to Peak Voltage 23 98 dBm 3 54 Vrms 10 00 Vpp 13 01 dBm 1 00 Vrms 2 828 Vpp 10 00 dBm 707 mVrms 2 000 Vpp 6 99 dBm 500 mVrms 1 414 Vpp 0 00 dBm 224 mVrms 632 mVpp 6 99 dBm 100 mVrms 283 mVpp 10 00 dBm 70 7 mVrms 200 mVpp 36 02 dBm 3 54 mVrms 10 0 mVpp For 75Q or 600Q loads use the following conversions dBm 759 dBm 509 1 76 dBm 6009 dBm 50Q 10 79 308 Chapter 7 Tutorial Modulation Modulation Modulation is the process of modifying a high frequency signal called the carrier signal with low frequency information called the modulating signal The carrier and modulating signals can have any waveshape but the carrier is usually a sine waveform The two most common types of modulation are amplitude modulation AM and frequency modulation FM These two forms of modulation modify the carrier s amplitude or frequency respectively according to the instantaneous value of the modulating signal A third type of modulation is frequency shift keying FSK where the output frequency shifts between two frequencies depending on the state of a digital modulating signal The function generator will accept an internal or external modulation source If you select the internal
204. l on the rear panel Trig In connector for an externally triggered burst The default is POS rising edge The SLOP query returns POS or NEG 193 Chapter 4 Remote Interface Reference Burst Mode Commands BURSt GATE POLarity NORMal INVerted BURSt GATE POLarity Select whether the function generator uses true high or true low logic levels on the rear panel Trig In connector for an externally gated burst The default is NORM true high logic The POL query returns NORM or INV OUTPut TRIGger SLOPe POSitive NEGative OUTPut TRIGger SLOPe Select a rising or falling edge for the trigger out signal When enabled using the OUTP TRIG command see below a TTL compatible square waveform with the specified edge is output from the rear panel Trig Out connector at the beginning of the burst Select POS to output a pulse with a rising edge or select NEG to output a pulse with a falling edge The default is POS The SLOP query returns POS or NEG e When the Immediate internal trigger source is selected TRIG SOUR IMM command the function generator outputs a square waveform with a 50 duty cycle from the Trig Out connector at the beginning of the burst The frequency of the waveform is equal to the specified burst period BURS INT PER command e When the External trigger source is selected TRIG SOUR EXT command or when the Gated mode is selecte
205. larity of the external gate signal on the Trig In connector The default is NORM true high logic BURSt GATE POLarity NORMal INVerted 91 Chapter 3 Features and Functions Burst Mode Waveform Frequency The waveform frequency defines the repetition rate of the burst waveform in the triggered and external gated modes In the triggered mode the number of cycles specified by the burst count is output at the waveform frequency In the external gated mode the waveform frequency is output when the external gate signal is true Keep in mind that the waveform frequency is different than the burst period which specifies the interval between bursts triggered mode only e Waveform frequency 2 mHz to 80 MHz limited to 1 MHz for ramps and 25 MHz for arbitrary waveforms The default waveform frequency is 1 kHz You can select a sine square ramp pulse or arbitrary waveform noise is allowed only in the gated burst mode and dc is not allowed e For sine and square waveforms frequencies above 25 MHz are allowed only with an infinite burst count e Front Panel Operation To set the waveform frequency press the Freq softkey for the selected function Then use the knob or numeric keypad to enter the desired frequency e Remote Interface Operation FREQuency lt frequency gt MINimum MAXimum You can also use the APPLy command to select the function frequency amplitude and offset with a single command
206. le the built in Sinc waveform does not use the full range of values between 1 and therefore its maximum offset is limited to 4 95 volts into 50 ohms The 0 DAC value is still used as the offset reference even if the waveform data points do not span the full range of the output DAC 148 Chapter 4 Remote Interface Reference Using the APPLy Command APPLy Command Syntax Because of the use of optional parameters in the APPLy commands enclosed in square brackets you must specify frequency to use the amplitude parameter and you must specify both frequency and amplitude to use the offset parameter For example the following command string is valid frequency and amplitude are specified but offset is omitted and therefore uses a default value APPL SIN 5 0E 3 3 0 However you cannot specify an amplitude or offset without specifying a frequency You can substitute MINimum MAXimum or DEFault in place of specific values for the frequency amplitude and offset parameters For example the following statement outputs a 3 Vpp sine wave at 80 MHz the maximum frequency for sine with a 2 5 volt offset APPL SIN MAX 3 0 2 5 The APPLy command performs the following operations e Sets the trigger source to Immediate equivalent to sending the TRIG SOUR IMM command e Turns off any modulation sweep or burst mode currently enabled and places the instrument in the continuous waveform
207. le to the HiLevel and LoLevel softkeys the current selection is highlighted 100 0mV p O Period HiLevel LoLevel 2 Enter the magnitude of the desired amplitude Using the numeric keypad enter the value 50 Select the units by p ja key below dBm CANCEL 3 Select the desired units Press the softkey that corresponds to the desired units When you select the units the function generator outputs the waveform with the displayed amplitude if the output is enabled For this example press MVpys eq BR Amp Period HiLevel LoLevel Note You can also enter the desired value using the knob and arrow keys 18 Chapter 1 Quick Start To Set the Output Amplitude You can easily convert the displayed amplitude from one unit to another For example the following steps show you how to convert the amplitude from Vrms to Vpp Enter the numeric entry mode Press the key to enter the numeric entry mode dBm CANCEL Select the new units Press the softkey that corresponds to the desired units The displayed value is converted to the new units For this example press the Vpp softkey to convert 50 mVrms to its equivalent in volts peak to peak pJ Period HiLevel To change the displayed amplitude by decades press the right arrow key to move the cursor to the units on the right side of the display Then rotate the knob to increase or decrease the displayed amplitude by decades EE aN
208. lects the largest de offset for the function and amplitude specified The default offset is 0 volts for all functions Limits Due to Amplitude The relationship between offset voltage and output amplitude is shown below Vmax is the maximum peak voltage for the selected output termination 5 volts for a 50Q load or 10 volts for a high impedance load Voffset lt Vmax Yep If the specified offset voltage is not valid the function generator will automatically adjust it to the maximum dc voltage allowed with the amplitude specified From the remote interface a Data out of range error will be generated and the offset will be adjusted as described Limits Due to Output Termination The offset limits are determined by the current output termination setting the APPLy command does not change the termination setting For example if you set the offset to 100 mVdc and then change the output termination from 50 ohms to high impedance the offset voltage displayed on the function generator s front panel will double to 200 mVdc and no error will be generated If you change from high impedance to 50 ohms the displayed offset will drop in half See the OUTP LOAD command on page 163 for more information Arbitrary Waveform Limitations For arbitrary waveforms the maximum offset and amplitude will be limited if the waveform data points do not span the full range of the output DAC Digital to Analog Converter For examp
209. lent 33250A has a fixed series output impedance of 50 ohms to the front panel Output connector If the actual load impedance is different than the value specified the displayed amplitude offset and high low levels will be incorrect e Ifyou change the output termination setting the displayed output amplitude offset and high low levels are automatically adjusted and no error will be generated For example if you set the amplitude to 10 Vpp and then change the output termination from 50 ohms to high impedance the amplitude displayed on the function generator s front panel will double to 20 Vpp If you change from high impedance to 50 ohms the displayed amplitude will drop in half e You cannot specify the output amplitude in dBm if the output termination is currently set to high impedance The units are automatically converted to Vpp See the VOLT UNIT command on page 165 for more information 163 Chapter 4 Remote Interface Reference Output Configuration Commands OUTPut POLarity NORMal INVerted OUTPut POLarity Invert the waveform relative to the offset voltage In the normal mode default the waveform goes positive during the first part of the cycle In the inverted mode the waveform goes negative during the first part of the cycle The POL query returns NORM or INV e As shown in the examples below the waveform is inverted relative to the offset voltage Any offset voltage p
210. litude will be automatically adjusted and no error will be generated For example if you set the amplitude to 10 Vpp and then change the output termination from 50 ohms to high impedance the amplitude displayed on the function generator s front panel will double to 20 Vpp If you change from high impedance to 50 ohms the displayed amplitude will drop in half For more information see the OUTP LOAD command on page 163 e You can set the output amplitude in Vpp Vrms or dBm by specifying the units as part of the VOLT command as shown below VOLT 3 0 VRMS Or you can use the VOLT UNIT command see page 165 to specify the output units for all commands that follow e You cannot specify the output amplitude in dBm if the output termination is currently set to high impedance The units are automatically converted to Vpp See the VOLT UNIT command on page 165 for more information 156 Chapter 4 Remote Interface Reference Output Configuration Commands Limits Due to Units Selection In some cases the amplitude limits are determined by the output units selected This may occur when the units are Vrms or dBm due to the differences in crest factor for the various output functions For example if you output a 5 Vrms square wave into 50 ohms and then change to the sine wave function the function generator will automatically adjust the output amplitude to 3 536 Vrms the upper limit for sine waves in Vrms F
211. ll be at the maximum amplitude When the modulating signal is at 5 volts then the output will be at the minimum amplitude AM INTernal FUNCtion SINusoid SQUare RAMP NRAMp TRIangle NOISe USER FUNCtion Select the shape of the modulating waveform Used only when the Internal modulation source is selected AM SOUR INT command You can use noise as the modulating waveshape but you cannot use noise pulse or dc as the carrier waveform The default is SIN The FUNC query returns SIN SQU RAMP NRAM TRI NOIS or USER e Select SQU for a square waveform with a 50 duty cycle L e Select RAMP for a ramp waveform with 100 symmetry e Select TRI for a ramp waveform with 50 symmetry S N e Select NRAM negative ramp for a ramp waveform with 0 symmetry e Ifyou select an arbitrary waveform as the modulating waveshape USER the waveform is automatically limited to 8K points Extra waveform points are removed using decimation 170 Chapter 4 Remote Interface Reference Amplitude Modulation AM Commands AM INTernal FREQuency lt frequency gt MINimum MAXimum AM INTernal FREQuency MINimum MAXimum Set the frequency of the modulating waveform Used only when the Internal modulation source is selected AM SOUR INT command Select from 2 mHz to 20 kHz The default is 100 Hz MIN 2 mHz MAX 20 kHz The FREQ query returns the
212. lly generated If you download more than 16 384 points a 65 536 point waveform is generated e The values 2047 and 2047 correspond to the peak values of the waveform if the offset is 0 volts For example if you set the output amplitude to 10 Vpp 2047 corresponds to 5V and 2047 corresponds to 5V e The maximum amplitude will be limited if the data points do not span the full range of the output DAC For example the built in Sinc waveform does not use the full range of values between 2047 and therefore its maximum amplitude is 6 087 Vpp into 50 ohms e The DATA DAC command overwrites the previous waveform in volatile memory and no error will be generated Use the DATA COPY command to copy the waveform to non volatile memory e Up to four user defined waveforms can be stored in non volatile memory Use the DATA DEL command to delete the waveform in volatile memory or any of the four user defined waveforms in non volatile memory Use the DATA CAT command to list all waveforms currently stored in volatile and non volatile memory as well as the five built in waveforms e After downloading the waveform data to memory use the FUNC USER command to choose the active waveform and the FUNC USER command to output it e To download binary data over the RS 232 interface you can use any handshake mode except XON XOFF and be sure to select Parity None 8 data bits You must also insert a pause
213. lution as well as waveform fidelity may be adversely affected when reducing the amplitude below the expected range change e The ONCE parameter has the same effect as turning autoranging ON and then OFF This parameter allows you to make a one time change to the amplifier attenuator setting before returning to the VOLT RANG AUTO OFF setting 160 Chapter 4 Remote Interface Reference Output Configuration Commands FUNCtion SQUare DCYCle lt percent gt MINimum MAXimum FUNCtion SQUare DCYCle MINimum MAXimum Set the duty cycle percentage for square waves Duty cycle represents the amount of time per cycle that the square wave is at a high level assuming that the waveform polarity is not inverted The default is 50 MIN selects the minimum duty cycle for the selected frequency and MAX selects the maximum duty cycle see restrictions below The DCYC query returns the current duty cycle setting in percent 20 Duty Cycle 80 Duty Cycle e Duty Cycle 20 to 80 frequency lt 25 MHz 40 to 60 25 MHz lt frequency lt 50 MHz 50 frequency gt 50 MHz e For square waveforms the APPLy command overrides the current duty cycle setting and automatically selects 50 e The duty cycle setting is remembered when you change from square wave to another function When you return to the square wave function the previous duty cycle is used e Limits Due to Frequency If the square wave fu
214. me from the 10 threshold to the 90 threshold of each edge You can vary the edge time from 5 ns to 1 ms see restrictions below The default edge time is 5 ns MIN 5 ns MAX 1 ms The TRAN query returns the edge time in seconds e The specified edge time must fit within the specified pulse width as shown below The function generator will adjust the edge time as needed to accommodate the specified pulse width From the remote interface a Data out of range error will be generated and the edge time will be adjusted as described Edge Time lt 0 625 X Pulse Width 168 Chapter 4 Remote Interface Reference Amplitude Modulation AM Commands Amplitude Modulation AM Commands See also Amplitude Modulation starting on page 67 in chapter 3 AM Overview The following is an overview of the steps required to generate an AM waveform The commands used for AM are listed on the next page Configure the carrier waveform Use the APPLy command or the equivalent FUNC FREQ VOLT and VOLT OFFS commands to select the function frequency amplitude and offset of the carrier waveform You can select a sine square ramp or arbitrary waveform for the carrier pulse noise and dc are not allowed Select the modulation source The function generator will accept an internal or external modulation source Select the modulation source using the AM SOUR command For an external source you can skip steps 3 and 4
215. ments by one for each calibration point a complete calibration may increase the value by many counts CALibration STRing lt quoted string gt CALibration STRing Store a message in non volatile calibration memory Storing a message will overwrite any message previously stored in memory The STR query reads the calibration message and returns a quoted string e The calibration message may contain up to 40 characters additional characters are truncated An example is shown below CAL STR Cal Due 01 June 2001 e You can record a calibration message only from the remote interface and only when the instrument is unsecured You can read the message either from the front panel or over the remote interface You can read the calibration message whether the instrument is secured or unsecured 240 Chapter 4 Remote Interface Reference An Introduction to the SCPI Language An Introduction to the SCPI Language SCPI Standard Commands for Programmable Instruments is an ASCII based instrument command language designed for test and measurement instruments Refer to Simplified Programming Overview starting on page 142 for an introduction to the basic techniques used to program the function generator over the remote interface SCPI commands are based on a hierarchical structure also known as a tree system In this system associated commands are grouped together under a common node or root thus forming swbsystems A por
216. minate a command string in place of a lt new line gt character A lt carriage return gt followed by a lt new line gt is also accepted Command string termination will always reset the current SCPI command path to the root level IEEE 488 2 Common Commands The IEEE 488 2 standard defines a set of common commandes that perform functions such as reset self test and status operations Common commands always begin with an asterisk are three characters in length and may include one or more parameters The command keyword is separated from the first parameter by a blank space Use a semicolon to separate multiple commands as shown below WARS TY CLS SESE 327 TORC 244 Chapter 4 Remote Interface Reference An Introduction to the SCPI Language SCPI Parameter Types The SCPI language defines several different data formats to be used in program messages and response messages Numeric Parameters Commands that require numeric parameters will accept all commonly used decimal representations of numbers including optional signs decimal points and scientific notation Special values for numeric parameters like MINimum MAXimum and DEFault are also accepted You can also send engineering unit suffixes with numeric parameters e g Mhz or Khz If only specific numeric values are accepted the function generator will automatically round the input numeric parameters The following command uses a numeric parameter
217. mode e Turns on the Output connector OUTP ON command but does not change the output termination setting OUTP LOAD command e Overrides the voltage autorange setting and automatically enables autoranging VOLT RANG AUTO command e For square waveforms overrides the current duty cycle setting and automatically selects 50 FUNC SQU DCYC command e For ramp waveforms overrides the current symmetry setting and automatically selects 100 FUNC RAMP SYMM command 149 Chapter 4 Remote Interface Reference Using the APPLy Command APPLy SINusoid lt frequency gt lt amplitude gt lt offset gt 1 Output a sine wave with the specified frequency amplitude and dc offset The waveform is output as soon as the command is executed APPLy SQUare lt frequency gt lt amplitude gt lt offset gt Output a square wave with the specified frequency amplitude and dc offset This command overrides the current duty cycle setting and automatically selects 50 The waveform is output as soon as the command is executed APPLy RAMP lt frequency gt lt amplitude gt lt offset gt Output a ramp wave with the specified frequency amplitude and dc offset This command overrides the current symmetry setting and automatically selects 100 The waveform is output as soon as the command is executed APPLy PULSe lt requency gt lt amplitude gt lt offset gt Output a pulse wave with the spec
218. mote interface The function generator is secured when shipped from the factory and the security code is set to AT33250A e Once you enter a security code that code must be used for both front panel and remote operation For example if you secure the function generator from the front panel you must use that same code to unsecure it from the remote interface and then select the Secure Off e Front Panel Operation Press Uii softkey from the Test Cal menu e Remote Interface Operation To unsecure the function generator send the following command with the correct security code CAL SECURE STATE OFF AT33250A To Secure Against Calibration You can secure the function generator either from the front panel or over the remote interface The function generator is secured when shipped from the factory and the security code is set to AT33250A e Once you enter a security code that code must be used for both front panel and remote operation For example if you secure the function generator from the front panel you must use that same code to unsecure it from the remote interface e Front Panel Operation Press uii and then select the Secure On softkey from the Test Cal menu e Remote Interface Operation To secure the function generator send the following command with the correct security code CAL SECURE STATE ON AT33250A 124 Chapter 3 Features and Functions Calibra
219. mpatible into 50Q gt 450 ns 1 MHz lt 4 Agilent 33250As CLOCK REFERENCE Phase Offset Range 360 to 360 Resolution 0 001 External Reference Input Lock Range 10 MHz 35 kHz Level 100 mVpp to 5 Vpp Impedance 1 KQ nominal ac coupled Lock Time lt 2s Internal Reference Output Frequency 10 MHz Level 632 mVpp 0 dBm nominal Impedance 50Q nominal ac coupled SYNC OUTPUT Level TTL compatible into gt 1 KQ Impedance 509 nominal 1 Time to change parameter and output new signal 2 Modulation or sweep off 3 Times for 5 digit integer and 12 digit real numbers 322 Chapter 8 Specifications Agilent 33250A Function Arbitrary Waveform Generator GENERAL SPECIFICATIONS Power Supply Power Consumption Operating Environment Operating Altitude Pollution Degree Storage Temperature Stored States Power On State Interface Language Dimensions WxHxD Bench Top Rack Mount Weight 100 240 V 410 for 50 60 Hz operation 100 127 V 410 for 50 400 Hz operation IEC 60664 CAT II 140 VA 0 CT to 55 C 80 R H to 40 C 3000 meters Indoor Use IEC 60664 Degree 2 30 C to 70 C Four 4 named user configurations Default or Last IEEE 488 and RS 232 standard SCPI 1997 IEEE 488 2 254 x 104 x 374 mm 213 x 89 x 348 mm 4 6 kg Safety Designed to EMC Tested to Acoustic Noise Warm Up Time Calibration Interval Warran
220. ms The default is 100 Hz MIN 5 Hz MAX based on the frequency of the carrier waveform as shown below The DEV query returns the deviation in hertz Max Deviation Carrier For Carrier lt 40 MHz Max Deviation Max Frequency Carrier For Carrier gt 40 MHz e The carrier frequency must always be greater than or equal to the deviation If you attempt to set the deviation to a value greater than the carrier frequency with FM enabled the function generator will automatically adjust the deviation to the maximum value allowed with the present carrier frequency From the remote interface a Data out of range error will be generated and the deviation will be adjusted as described e The sum of the carrier frequency and deviation must be less than or equal to the maximum frequency for the selected function plus 100 kHz 80 1 MHz for sine and square 1 1 MHz for ramp and 25 1 MHz for arbitrary waveforms If you attempt to set the deviation to a value that is not valid the function generator will automatically adjust it to the maximum value allowed with the present carrier frequency From the remote interface a Data out of range error will be generated and the deviation will be adjusted as described 174 FM STATe OFF ON FM STATe Disable or enable FM To avoid multiple waveform changes you can enable FM after you have set up the other modulation parameters The default is OFF The STAT query ret
221. n 54 Chapter 3 Features and Functions Output Configuration Arbitrary Waveform Limitations For arbitrary waveforms the maximum offset and amplitude will be limited if the waveform data points do not span the full range of the output DAC Digital to Analog Converter For example the built in Sinc waveform does not use the full range of values between 1 and therefore its maximum offset is limited to 4 95 volts into 50 ohms You can also set the offset by specifying a high level and low level For example if you set the high level to 2 volts and the low level to 3 volts the resulting amplitude is 5 Vpp with an offset voltage of 500 mV For dc volts the output level is actually controlled by setting the offset voltage You can set the dc level to any value between 5 Vdc into 50 ohms or 10 Vdc into an open circuit To select dc volts from the front panel press Wily and then select the DC On softkey Press the Offset softkey to set the desired offset voltage level Front Panel Operation To set the dc offset press the Offset softkey for the selected function Then use the knob or numeric keypad to enter the desired offset To set the offset using a high level and low level press the Offset softkey again to toggle to the HiLevel and LoLevel softkeys Remote Interface Operation VOLTage OFFSet lt offset gt MINimum MAXimum Or you can set the offset by specifying a high level and low level using the
222. n frequency amplitude and offset with a single command 79 Chapter 3 Features and Functions Frequency Shift Keying FSK Modulation FSK Hop Frequency The maximum alternate or hop frequency depends on the function selected as shown below The default is 100 Hz for all functions Function Minimum Frequency Maximum Frequency Sine 1 wHz 80 MHz Square 1 wHz 80 MHz Ramp 1 wHz 1 MHz Arbs 1 wHz 25 MHz e The internal modulating waveform is a square wave with a 50 duty cycle e When the External source is selected the output frequency is determined by the signal level on the rear panel Trig In connector When a logic low level is present the carrier frequency is output When a logic high level is present the hop frequency is output e Front Panel Operation To set the hop frequency press the Hop Freq softkey Then use the knob or numeric keypad to enter the desired frequency e Remote Interface Operation FSKey FREQuency lt frequency gt MINimum MAXimum FSK Rate The FSK rate is the rate at which the output frequency shifts between the carrier frequency and the hop frequency when you select the internal FSK source e FSK rate internal source 2 mHz to 1 MHz The default is 10 Hz e The FSK rate is ignored when the external FSK source is selected e Front Panel Operation To set the FSK rate press the FSK Rate softkey Then use the knob or numeric keypad to
223. n outside of the environmental specifications for the product or improper site preparation or maintenance The design and implementa tion of any circuit on this product is the sole responsibil ity of the Buyer Agilent does not warrant the Buyer s circuitry or malfunctions of Agilent products that result from the Buyer s circuitry In addition Agilent does not warrant any damage that occurs as a result of the Buyer s circuit or any defects that result from Buyer supplied products Agilent makes no other warranty expressed or implied whether written or oral with respect to this product and specifically disclaims any implied warranty or condition of merchantability fitness for a particular purpose or satisfactory quality Exclusive Remedies The remedies provided herein are the Buyer s sole and exclu sive remedies Agilent shall not be liable for any direct indi rect special incidental or consequential damages includ ing lost profit whether based on warranty contract tort or any other legal theory Notice The information contained in this document is subject to change without notice Agilent makes no warranty of any kind with regard to this material including but not limited to the implied warranties of merchant ability and fitness for a particular purpose Agilent shall not be liable for errors contained herein or for incidental or consequential damages in connection with the f
224. nc Output Aa 1 Pae Petebedepetetetetefetetetetepedeteted Main Output Three Cycle Burst Waveform For bursts the trigger source can be an external signal an internal timer the key or a command received from the remote interface The input for external trigger signals is the rear panel Trig In connector This connector accepts TTL compatible levels and is referenced to chassis ground not floating ground When not used as an input the Trig In connector can be configured as an output to enable the 33250A to trigger other instruments at the same time as its internal trigger occurs The effect of a trigger can be delayed up to 85 seconds in increments of 100 picoseconds to synchronize the start of the burst with other events You can also insert a trigger delay to compensate for the cable delays and response times of other instruments in your system An N Cycle burst always begins and ends at the same point in the waveform called the start phase A starting phase of 0 corresponds to the beginning of the waveform record and 360 corresponds to the end of the waveform record 315 Chapter 7 Tutorial Burst As an example suppose that your application requires two 5 MHz sine waveforms that are exactly 90 out of phase from one another You can use two 33250A s as described below First designate one function generator as the master and the other as the slave As shown below connect the
225. nction is selected and you change to a frequency that cannot produce the current duty cycle the duty cycle is automatically adjusted to the maximum value for the new frequency For example if you currently have the duty cycle set to 70 and then change the frequency to 60 MHz the function generator will automatically adjust the duty cycle to 50 the upper limit for this frequency From the remote interface a Settings conflict error will be generated and the duty cycle will be adjusted as described e Ifyou select a square waveform as the modulating waveform for AM or FM the duty cycle setting does not apply The function generator always uses a square waveform with a 50 duty cycle 161 Chapter 4 Remote Interface Reference Output Configuration Commands FUNCtion RAMP SYMMetry lt percent gt MINimum MAXimum FUNCtion RAMP SYMMetry MINimum MAXimum Set the symmetry percentage for ramp waves Symmetry represents the amount of time per cycle that the ramp wave is rising assuming that the waveform polarity is not inverted You can set the symmetry to any value from 0 to 100 The default is 100 MIN 0 MAX 100 The SYMM query returns the current symmetry setting in percent 0 Symmetry 100 Symmetry e For ramp waveforms the APPLy command overrides the current symmetry setting and automatically selects 100 e The symmetry setting is remembered when you change from ramp wave to another function When you
226. nerated and the period will be adjusted as described PULSe WIDTh lt seconds gt MINimum MAXimum PULSe WIDTh MINimum MAXimum Set the pulse width in seconds The pulse width represents the time from the 50 threshold of the rising edge of the pulse to the 50 threshold of the next falling edge You can vary the pulse width from 8 ns to 2000 seconds see restrictions below The default pulse width is 100 us MIN 8 ns MAX 2000 seconds The WIDT query returns the pulse width in seconds e The minimum pulse width is affected by the period For period gt 20 seconds minimum pulse width 1 ps For period gt 200 seconds minimum pulse width 10 ps e The specified pulse width must be less than the difference between the period and the edge time as shown below The function generator will adjust the pulse width as needed to accommodate the specified period From the remote interface a Settings conflict error will be generated and the pulse width will be adjusted as described Pulse Width lt Period 1 6 X Edge Time e The pulse width must also be greater than the total time of one edge as shown below Pulse Width gt 1 6 X Edge Time 167 Chapter 4 Remote Interface Reference Pulse Configuration Commands PULSe TRANsition lt seconds gt MINimum MAXimum PULSe TRANsition MINimum MAXimum Set the edge time in seconds for both the rising and falling edges The edge time represents the ti
227. ng a Serial Poll is handled automatically by the IEEE 488 bus interface hardware Unlike ASCII commands and some other GPIB commands a Serial Poll is executed immediately and does not involve the instrument s main processor Therefore the status indicated by a Serial Poll may not necessarily indicate the effect of the most recent command Use the OPC command to guarantee that commands previously sent to the instrument have completed before executing a Serial Poll Using STB to Read the Status Byte The STB command is similar to a Serial Poll but it is processed like any other ASCII instrument command The STB command returns the same result as a Serial Poll but bit 6 is not cleared as long as the enabled conditions remain The STB command is not handled automatically by the IEEE 488 bus interface hardware and will be executed only after previous commands have completed You cannot clear an SRQ using the STB command 229 Chapter 4 Remote Interface Reference The SCPI Status System Using the Message Available Bit MAV You can use the Status Byte Message Available bit bit 4 to determine when data is available to read into your computer The instrument subsequently clears bit 4 only after all messages have been read from the output buffer To Interrupt Your Computer Using SRQ 1 4 5 Send a Device Clear message to return the function generator to a responsive state and clear it s
228. ngs learn string You can then send the string back to the instrument to restore this state at a later time For proper operation do not modify the returned string before sending it to the function generator The returned string will contain about 1 500 characters 216 Chapter 4 Remote Interface Reference System Related Commands OPC Set the Operation Complete bit bit 0 in the Standard Event register after the previous commands have been executed Other commands may be executed before the bit is set This command is used in the triggered sweep or triggered burst modes to provide a way to poll or interrupt the computer when the sweep or burst is complete OPC Return 1 to the output buffer after the previous commands have been executed Other commands cannot be executed until this command completes Used in the triggered sweep and triggered burst modes only WAI Wait for all pending operations to complete before executing any additional commands over the interface Used in the triggered sweep and triggered burst modes only 217 Chapter 4 Remote Interface Reference Interface Configuration Commands Interface Configuration Commands See also Remote Interface Configuration on page 118 in chapter 3 SYSTem INTerface GPIB RS232 Select the remote interface Only one interface can be enabled at a time The GPIB interface is selected when the function generator is shipped from the factory Th
229. nics that are aliased or folded back into the passband of the function generator These spurs are most significant when there is a simple fractional relationship between the signal frequency and the function generator s sampling frequency 200 MHz For example at 75 MHz the DAC produces harmonics at 150 MHz and 225 MHz These harmonics which are 50 MHz and 25 MHz from the function generator s 200 MHz sampling frequency will appear as spurs at 50 MHz and 25 MHz Another source of non harmonic spurs is the coupling of unrelated signal sources such as the microprocessor clock into the output signal These spurs usually have a constant amplitude lt 75 dBm or 112 pVpp regardless of the signal s amplitude and are most troublesome at signal amplitudes below 100 mVpp To obtain low amplitudes with minimum spurious content keep the function generator s output level relatively high and use an external attenuator if possible 302 Chapter 7 Tutorial Signal Imperfections Phase Noise Phase noise results from small instantaneous changes in the output frequency jitter It is seen as an elevation of the apparent noise floor near the fundamental frequency and increases at 6 dBc octave with the carrier frequency The 33250A s phase noise specification represents the sum of all noise components in a 30 kHz band centered on the fundamental frequency This integrated phase noise is related to jitter by the following
230. ns of the function generator e Direct Digital Synthesis on page 295 e Creating Arbitrary Waveforms on page 298 e Square Waveform Generation on page 300 e Pulse Waveform Generation on page 300 e Signal Imperfections on page 302 e Output Amplitude Control on page 304 e Ground Loops on page 305 e Attributes of AC Signals on page 307 e Modulation on page 309 e Frequency Sweep on page 312 e Burst on page 315 You can use an arbitrary waveform generator in a variety of applications where it might be otherwise difficult or impossible to generate complex output waveforms With an arbitrary waveform generator signal imperfections such as rise time ringing glitches noise and random timing variations can be easily simulated in a controlled manner Physics chemistry biomedicine electronics mechanics and other fields can benefit from the versatility of an arbitrary waveform generator Wherever things vibrate pump pulse bubble burst or change with time in any way there are possible applications limited only by your ability to specify the waveform data 294 Chapter 7 Tutorial Direct Digital Synthesis Direct Digital Synthesis Digital signal processing methods are used in many everyday applications Whether it is a digital audio compact disc player an electronic synthesized piano or a voice synthesized telephone message system complex waveforms can be easily created or reproduced using digital signal gen
231. nstrument state in one of four non volatile storage locations A fifth storage location automatically holds the power down configuration of the instrument When power is restored the instrument can automatically return to its state before power down Select the desired storage location and then select the Store State softkey Press STATE_1 Stat Select a custom name for the selected location If desired you can assign a custom name to each of the four locations IRE TE CANCEL e The name can contain up to 12 characters The first character must be a letter but the remaining characters can be letters numbers or the underscore character _ e To add additional characters press the right arrow key until the cursor is to the right of the existing name and then turn the knob e To delete all characters to the right of the cursor position press e To use numbers in the name you can enter them directly from the numeric keypad Use the decimal point from the numeric keypad to add the underscore character _ to the name Store the instrument state Press the STORE STATE softkey The instrument stores the selected function frequency amplitude dc offset duty cycle symmetry as well as any modulation parameters in use The instrument does not store volatile waveforms created in the arbitrary waveform function 43 Chapter 2 Front Panel Menu Operation To Configure the Remote Interface
232. o Local command for GPIB or send the SYST LOCAL command for RS 232 215 Chapter 4 Remote Interface Reference System Related Commands RST Reset the function generator to its factory default state see Factory Default Settings on page 127 independent of the MEM STAT REC AUTO command setting This command will abort a sweep or burst in progress and will re enable the front panel display if it was previously disabled DISP OFF command TST Perform a complete self test of the function generator Returns 0 PASS or 1 FAIL If the test fails one or more error messages will be generated to provide additional information on the failure Use the SYST ERR command to read the error queue see page 213 SYSTem VERSion Query the function generator to determine the present SCPI version Returns a string in the form YYYY V where YYYY represents the year of the version and V represents a version number for that year e g 1997 0 SYSTem BEEPer Issue a single beep immediately SYSTem BEEPer STATe OFF ON SYSTem BEEPer STATe Disable or enable the tone heard when an error is generated from the front panel or over the remote interface The current selection is stored in non volatile memory The STAT query returns 0 OFF or 1 ON LRN Query the function generator and return a string of SCPI commands containing the current setti
233. o a frequency that cannot produce the current duty cycle the duty cycle is automatically adjusted to the maximum value for the new frequency For example if you currently have the duty cycle set to 70 and then change the frequency to 60 MHz the function generator will automatically adjust the duty cycle to 50 the upper limit for this frequency From the remote interface a Settings conflict error will be generated and the duty cycle will be adjusted as described 155 Chapter 4 Remote Interface Reference Output Configuration Commands VOLTage lt amplitude gt MINimum MAXimum VOLTage MINimum MAXimum Set the output amplitude The default amplitude is 100 mVpp into 50Q for all functions MIN selects the smallest amplitude 1 mVpp into 50Q MAX selects the largest amplitude for the selected function at most 10 Vpp into 50Q depending on the selected function and offset voltage The VOLT query returns the output amplitude for the function currently selected Values are always returned in the units set by the most recent VOLT UNIT command e Offset Voltage Limitations The relationship between output amplitude and offset voltage is shown below Vmax is the maximum peak voltage for the selected output termination 5 volts for a 50Q load or 10 volts for a high impedance load Vpp lt 2X Vmax Voffset e Limits Due to Output Termination If you change the output termination setting the displayed output amp
234. o the specified location the default name is returned AUTO_RECALL STATE_1 STATE_2 STATE_3 or STATE_4 e The name can contain up to 12 characters The first character must be a letter A Z but the remaining characters can be letters numbers 0 9 or the underscore character _ Blank spaces are not allowed An error is generated if you specify a name with more than 12 characters An example is shown below MEM STATE NAME 1 TEST _WFORM_1 e From the front panel you cannot assign a custom name to storage location 0 e Ifyou do not specify a name note that the name parameter is optional the default name is assigned to that state This provides a way to clear a name however the stored state is not deleted e The function generator will not prevent you from assigning the same name to different storage locations For example you can assign the same name to locations 1 and 2 MEMory STATe DELete 0 1 2 3 4 Delete the contents of the specified storage location If you have assigned a user defined name to a location MEM STAT NAME command this command also removes the name that you assigned and restores the default name AUTO_RECALL STATE_1 STATE_2 etc Note that you cannot recall the instrument state from a storage location that is empty An error is generated if you attempt to recall a deleted state
235. of approximately 1 ms between sending the header and sending the binary block See page 219 for more information on configuring the RS 282 interface 201 Chapter 4 Remote Interface Reference Arbitrary Waveform Commands e The following statement shows how to use the DATA DAC command to download seven integer points using the binary block format see also Using the EEE 488 2 Binary Block Format below DATA DAC VOLATILE 214 Binary Data e The following statement shows how to use the DATA DAC command to download five integer points in decimal format DATA DAC VOLATILE 2047 1024 0 1024 2047 Using the IEEE 488 2 Binary Block Format In the binary block format a block header precedes the waveform data The block header has the following format 5 32768 Start of Even Number of Bytes to Follow Data Block 32 768 bytes 16 384 points Number of Digits to Follow The function generator represents binary data as 16 bit integers which are sent as two bytes Therefore the total number of bytes is always twice the number of data points in the waveform and must always be an even number For example 32 768 bytes are required to download a waveform with 16 384 points Use the FORM BORD command to select the byte order for binary transfers in block mode If you specify FORM BORD NORM default the most significant byte MSB of each data point is assumed first If you specify FOR
236. of the desired output waveform must be less than half of the sampling frequency 100 MHz for the 33250A 297 Chapter 7 Tutorial Creating Arbitrary Waveforms Creating Arbitrary Waveforms For most applications it is not necessary to create an arbitrary waveform with a specific number of points since the function generator will repeat points or interpolate as necessary to fill waveform memory For example if you specify 100 points each waveform point will be repeated an average of 16 384 100 or 163 84 times For the 33250A you do not have to change the length of the waveform to change its output frequency All you have to do is create a waveform of any length and then adjust the function generator s output frequency However in order to get the best results and minimize voltage quantization errors it is recommended that you use the full range of the waveform DAC use all 4 096 levels When entering waveform points from the function generator s front panel you are not required to enter the points at evenly spaced intervals in time You can always add additional points as needed where the waveform is more complex From the front panel only you can also use linear interpolation to smooth the transition between waveform points These features make it possible to create useful arbitrary waveforms using a relatively small number of points With the 33250A you can output an arbitrary waveform to an upper frequency limi
237. ogram the function generator If you are a first time user of the SCPI language please refer to these sections to become 130 Chapter 4 Remote Interface Reference SCPI Command Summary SCPI Command Summary Throughout this manual the following conventions are used for SCPI command syntax for remote interface programming e Square brackets indicate optional keywords or parameters e Braces enclose parameters within a command string e Triangle brackets lt gt enclose parameters for which you must substitute a value e A vertical bar separates multiple parameter choices The APPLy Commands see page 144 for more information APPLy SINusoid lt frequency gt lt amplitude gt lt offset gt SQUare lt frequency gt lt amplitude gt lt offset gt RAMP lt frequency gt lt amplitude gt lt offset gt PULSe lt frequency gt lt amplitude gt lt offset gt 1 NOISe lt frequency DEF gt lt amplitude gt lt offset gt DC lt frequency DEF gt lt amplitude gt DEF gt lt offset gt USER lt frequency gt lt amplitude gt lt offset gt APPLy 1 This parameter has no effect for this command but you MUST specify a value or DEFault 131 Chapter 4 Remote Interface Reference SCPI Command Summary Output Configuration Commands see page 153 for more information FUNCtion FUNCtion
238. on Returns a string in the form YYYY V where YYYY represents the year of the version and V represents a version number for that year e g 1997 0 117 Chapter 3 Features and Functions Remote Interface Configuration Remote Interface Configuration This section gives information on configuring the function generator for remote interface communication For information on configuring the instrument from the front panel see To Configure the Remote Interface starting on page 44 For information on the SCPI commands available to program the function generator over the remote interface see chapter 4 Remote Interface Reference starting on page 129 GPIB Address Each device on the GPIB IEEE 488 interface must have a unique address You can set the function generator s address to any value between 0 and 30 The address is set to 10 when the function generator is shipped from the factory The GPIB address is displayed at power on You can set the GPIB address from the front panel only e The address is stored in non volatile memory and does not change when power has been off or after a remote interface reset e Your computer s GPIB interface card has its own address Be sure to avoid using the computer s address for any instrument on the interface bus and then select the GPIB Address e Front Panel Operation Press vitity softkey from the I O menu See also To
239. on OPC Set the Operation Complete bit bit 0 in the Standard Event register after the previous commands have completed When used with a bus triggered sweep or burst you may have the opportunity to execute commands after the OPC command and before the Operation Complete bit is set in the register 238 Chapter 4 Remote Interface Reference Calibration Commands Calibration Commands For an overview of the calibration features of the function generator refer to Calibration Overview in chapter 3 starting on page 123 For a detailed discussion of the function generator s calibration procedures refer to chapter 4 in the Agilent 33250A Service Guide CALibration SECure STATe OFF ON lt code gt CALibration SECure STATe Unsecure or secure the instrument for calibration The calibration code may contain up to 12 characters The STAT query returns 0 OFF or 1 ON CALibration SETup lt 0 1 2 3 115 gt CALibration SETup Configure the function generator s internal state for each of the calibration steps to be performed The SET query reads the calibration setup number and returns a value from 0 to 115 CALibration VALue lt value gt CALibration VALue Specify the value of the known calibration signal as outlined in the calibration procedures in the Agilent 33250A Service Guide Use the CAL SET command to configure the function generator s internal
240. on starting on page 78 in chapter 3 FSK Overview The following is an overview of the steps required to generate an FSK modulated waveform The commands used for FSK are listed on the next page Configure the carrier waveform Use the APPLy command or the equivalent FUNC FREQ VOLT and VOLT OFFS commands to select the function frequency amplitude and offset of the carrier waveform You can select a sine square ramp or arbitrary waveform for the carrier pulse noise and dc are not allowed Select the FSK source The function generator will accept an internal or external FSK source Select the FSK source using the FSK SOUR command Select the FSK hop frequency Set the alternate or hop frequency to any value from 1 uHz to 80 MHz limited to 1 MHz for ramps and 25 MHz for arbitrary waveforms using the FSK FREQ command Set the FSK rate Set the FSK rate to any value from 2 mHz to 1 MHz using the FSK INT RATE command internal FSK source only The FSK rate sets the pace at which the output frequency shifts between the carrier frequency and the hop frequency Enable FSK modulation After you have set up the other FSK parameters use the FSK STAT ON command to enable FSK modulation 176 Chapter 4 Remote Interface Reference Frequency Shift Keying FSK Commands FSK Commands Use the APPLy command or the equivalent FUNC FREQ VOLT and VOLT OFFS commands to configure
241. op bit Input buffer overrun Too many characters have been sent to the function generator while configured to use the RS 232 interface This error typically occurs when you have selected no handshaking of data between the computer and the function generator To avoid this error select one of the handshake modes available for the 33250A see Remote Interface Configuration on page 118 for more information 266 410 420 430 440 Chapter 5 Error Messages Query Errors Query Errors Query INTERRUPTED A command was received but the output buffer contained data from a previous command the previous data is lost Query UNTERMINATED The function generator was addressed to talk i e to send data over the interface but a command has not been received which sends data to the output buffer For example you may have executed an APPLy command which does not generate data and then attempted an Enter statement to read data from the interface Query DEADLOCKED A command was received which generates too much data to fit in the output buffer and the input buffer is also full Command execution continues but all data is lost Query UNTERMINATED after indefinite response The IDN command must be the last query command within a command string Example IDN SYST VERS 267 501 to 504 514 522 523 580 590 Chapter 5 Error Messages Instrument Errors Instrument Errors 50
242. or the frequency previously selected When you change functions the same frequency is used if the present value is valid for the new function To set the waveform period instead press the Freq softkey again to toggle to the Period softkey the current selection is highlighted 1 000 000 00 kHz fy VF Period HiLevel LoLevel Enter the magnitude of the desired frequency Using the numeric keypad enter the value 1 2 Select the units by p a key below Select the desired units Press the softkey that corresponds to the desired units When you select the units the function generator outputs a waveform with the displayed frequency if the output is enabled For this example press MHz 1 200 000 00MHz fy Period HiLevel LoLevel VF Note You can also enter the desired value using the knob and arrow keys 17 Chapter 1 Quick Start To Set the Output Amplitude To Set the Output Amplitude At power on the function generator outputs a sine wave with an amplitude of 100 mV peak to peak into a 50Q termination The following steps show you how to change the amplitude to 50 mVrms 1 Press the Ampl softkey The displayed amplitude is either the power on value or the amplitude previously selected When you change functions the same amplitude is used if the present value is valid for the new function To set the amplitude using a high level and low level press the Ampl softkey again to togg
243. or to a responsive state Different programming languages and IEEE 488 interface cards provide access to this capability through their own unique commands The status registers the error queue and all configuration states are left unchanged when a Device Clear message is received Device Clear performs the following actions e The function generator s input and output buffers are cleared e The function generator is prepared to accept a new command string e For RS 232 operation sending the lt Break gt character will perform the equivalent operations of the IEEE 488 Device Clear message e An overlapped command if any will be terminated with no Operation Complete indication applies to the TRG command Any sweep or burst in progress will be aborted immediately 246 Error Messages Error Messages e Errors are retrieved in first in first out FIFO order The first error returned is the first error that was stored Errors are cleared as you read them The function generator beeps once each time an error is generated unless you have disabled the beeper e If more than 20 errors have occurred the last error stored in the queue the most recent error is replaced with Queue overflow No additional errors are stored until you remove errors from the queue If no errors have occurred when you read the error queue the function generator responds with No error e The error queue is cleared by the
244. ou cannot use noise pulse or dc as the carrier waveform The default is SIN The FUNC query returns SIN SQU RAMP NRAM TRI NOIS or USER e Select SQU for a square waveform with a 50 duty cycle L e Select RAMP for a ramp waveform with 100 symmetry ig e Select TRI for a ramp waveform with 50 symmetry ra e Select NRAM negative ramp for a ramp waveform with 0 symmetry e Ifyou select an arbitrary waveform as the modulating waveshape USER the waveform is automatically limited to 8K points Extra waveform points are removed using decimation 173 Chapter 4 Remote Interface Reference Frequency Modulation FM Commands FM INTernal FREQuency lt frequency gt MINimum MAXimum FM INTernal FREQuency MINimum MAXimum Set the frequency of the modulating waveform Used only when the Internal modulation source is selected FM SOUR INT command Select from 2 mHz to 20 kHz The default is 10 Hz MIN 2 mHz MAX 20 kHz The FREQ query returns the internal modulating frequency in hertz FM DEViation lt peak deviation in Hz gt MINimum MAXimum FM DEViation MINimum MAXimum Set the peak frequency deviation in hertz This value represents the variation in frequency of the modulating waveform from the carrier frequency Select any value from 5 Hz to 40 05 MHz limited to 550 kHz for ramps and 12 55 MHz for arbitrary wavefor
245. output buffer e g CLEAR 710 Clear the event registers and error queue using the CLS command Set up the enable register masks Use the ESE command to configure the Standard Event enable register and the SRE command to configure the Status Byte enable register Send the OPC command and read the result to ensure synchronization Enable your computer s IEEE 488 SRQ interrupt To Determine When a Command Sequence is Completed 1 Send a Device Clear message to return the function generator to a responsive state and clear it s output buffer e g CLEAR 710 Clear the event registers and error queue using the CLS command Enable the Operation Complete bit bit 0 in the Standard Event register by executing the ESE 1 command Send the OPC command and read the result to ensure synchronization Execute your command string to program the desired configuration and then execute the OPC command as the last command When the command sequence is completed the Operation Complete bit bit 0 is set in the Standard Event register Use a Serial Poll to check to see when bit 5 routed from the Standard Event register is set in the Status Byte condition register You could also configure the function generator for an SRQ interrupt by sending SRE 32 Status Byte enable register bit 5 230 Chapter 4 Remote Interface Reference The SCPI Status System The Questionable Da
246. outputs a square waveform with a 50 duty cycle from the Trig Out connector at the beginning of the sweep or burst The period of the waveform is equal to the specified sweep time or burst period e When the External trigger source is selected the function generator automatically disables the trigger out signal The Trig Out connector cannot be used for both operations at the same time an externally triggered waveform uses the same connector to trigger the sweep or burst e When the Bus software trigger source is selected the function generator outputs a pulse gt 1 ps pulse width from the Trig Out connector at the beginning of each sweep or burst e Front Panel Operation After enabling sweeps or burst press the Trigger Setup softkey Then select the desired edge by pressing the Trig Out softkey e Remote Interface Operation OUTPut TRIGger SLOPe POSitive NEGative OUTPut TRIGger OFF ON 102 Chapter 3 Features and Functions Arbitrary Waveforms Arbitrary Waveforms There are five built in arbitrary waveforms stored in non volatile memory You can also store up to four user defined waveforms in non volatile memory in addition to one in volatile memory Each waveform can contain between 1 a de voltage and 65 536 64K data points Refer to chapter 7 Tutorial for more information on the internal operation of downloading and outputting an arbitrary waveform To Create and Store an Arbitrary Wav
247. overwritten and no error will be generated You can store the instrument state in any of the five storage locations However you can only recall a state from a location that contains a previously stored state From the remote interface only you can use storage location 0 to store a fifth instrument state you cannot store to this location from the front panel However note that location 0 is automatically overwritten when power is cycled the instrument state previously stored will be overwritten The state storage feature remembers the selected function including arbitrary waveforms frequency amplitude dc offset duty cycle symmetry as well as any modulation parameters in use If you delete an arbitrary waveform from non volatile memory after storing the instrument state the waveform data is lost and the function generator will not output the waveform when the state is recalled The built in exponential rise waveform is output in place of the deleted waveform 209 Chapter 4 Remote Interface Reference State Storage Commands e When power is turned off the function generator automatically stores its state in storage location 0 You can configure the function generator to automatically recall the power down state when power is restored See the MEM STAT REC AUTO command on page 212 for more information e The front panel display state DISP command is saved when you store the ins
248. ovides additional information on the most recent message to be displayed Local Language Help The built in help system in available in multiple languages All messages context sensitive help and help topics appear in the selected language The menu softkey labels and status line messages are not translated To select the local language press the key press the System softkey and then press the Help In softkey Select the desired language 26 Chapter 1 Quick Start To Rack Mount the Function Generator To Rack Mount the Function Generator You can mount the Agilent 33250A in a standard 19 inch rack cabinet using one of two optional kits available Instructions and mounting hardware are included with each rack mounting kit Any Agilent System IT instrument of the same size can be rack mounted beside the Agilent 33250A Note Remove the carrying handle and the front and rear rubber bumpers before rack mounting the instrument N t T DO Og poopn s O5 To remove the handle rotate it to vertical and pull the ends outward HHHH HH m HHI UHHH t ad Front Rear bottom view To remove the rubber bumper stretch a corner and then slide it off 27 Chapter 1 Quick Start To Rack Mount the Function Generator To rack mount a single instrument order adapter kit 5063 9240
249. ownloaded to non volatile memory e A series of quoted strings separated with commas is returned as shown in the example below VOLATILE EXP_RISE EXP_FALL NEG _RAMP SINC CARDIAC TEST1_ARB TEST2_ARB e Use the DATA DEL command to delete the waveform in volatile memory or any of the user defined waveforms in non volatile memory DATA NVOLatile CATalog List the names of all user defined arbitrary waveforms downloaded to non volatile memory Returns the names of up to four waveforms e A series of quoted strings separated with commas is returned as shown in the example below If no user defined waveforms are currently downloaded the command returns a null string TEST1_ARB TEST2_ARB TEST3_ARB TEST4_ARB e Use the DATA DEL command to delete any of the user defined waveforms in non volatile memory DATA NVOLatile FREE Query the number of non volatile memory slots available to store user defined waveforms Returns the number of memory slots available to store user defined waveforms Returns 0 memory is full 1 2 3 or 4 206 Chapter 4 Remote Interface Reference Arbitrary Waveform Commands DATA DELete lt arb name gt Delete the specified arbitrary waveform from memory You can delete the waveform in volatile memory or any of the four user defined waveforms in non volatile memory You cannot delete
250. panel key The function generator initiates one sweep or outputs one burst for each time you press the key The key is illuminated while the function generator is waiting for a manual trigger the key is disabled when in remote 99 Chapter 3 Features and Functions Triggering External Triggering In the external trigger mode the function generator will accept a hardware trigger applied to the rear panel Trig In connector The function generator initiates one sweep or outputs one burst each time Trig In receives a TTL pulse with the specified edge See also Trigger Input Signal on the following page e Front Panel Operation The external trigger mode is like the manual trigger mode except that you apply the trigger to the Trig In connector To select the external source press the Trigger Setup softkey and then select the Source Ext softkey To specify whether the function generator triggers on the rising or falling edge press the Trigger Setup softkey and then select the desired edge by pressing the Slope softkey e Remote Interface Operation TRIGger SOURce EXTernal Use the following command to specify whether the function generator triggers on the rising or falling edge TRIGger SLOPe POSitive NEGative Software Bus Triggering The bus trigger mode is available only from the remote interface This mode is similar to the manual trigger mode from the front panel but you trigger the function generator by s
251. points but there may be some loss of vertical resolution e Ifyou decrease the voltage limits some of the existing points could potentially exceed the new limits The waveform editor will reduce the voltage levels of such points to equal the new limits e Ifyou select an arbitrary waveform as the modulating waveshape for AM or FM the waveform is automatically limited to 8K points Extra waveform points are removed using decimation 108 Chapter 3 Features and Functions System Related Operations System Related Operations This section gives information on topics such as instrument state storage power down recall error conditions self test and front panel display control This information is not directly related to waveform generation but is an important part of operating the function generator Instrument State Storage The function generator has five storage locations in non volatile memory to store instrument states The locations are numbered 0 through 4 The function generator automatically uses location 0 to hold the state of the instrument at power down You can also assign a user defined name to each of the locations 1 through 4 for use from the front panel e You can store the instrument state in any of the five storage locations However you can only recall a state from a location that contains a previously stored state e From the remote interface only you can use storage location 0 to store a
252. potential 306 Chapter 7 Tutorial Attributes of AC Signals Attributes of AC Signals The most common ac signal is a sine wave In fact any periodic signal can be represented as the sum of different sine waves The magnitude of a sine wave is usually specified by its peak peak to peak or root mean square RMS value All of these measures assume that the waveform has zero offset voltage aa VPeak Vous 0 707 Veeak VPk Pk The peak voltage of a waveform is the maximum absolute value of all points in the waveform The peak to peak voltage is the difference between the maximum and minimum The RMS voltage is found by summing the squares of the voltages of every point in the waveform dividing the sum by the number of points and then taking the square root of that quotient The RMS value of a waveform also represents the one cycle average power in the signal Power Vgys Ri Crest factor is the ratio of a signal s peak value to its RMS value and will differ according to waveshape The table below shows several common waveforms with their respective crest factors and RMS values Waveform Crest Factor Shape C F AC RMS AC DC RMS fos 307 Chapter 7 Tutorial Attributes of AC Signals You may occasionally see ac levels specified in decibels relative to 1 milliwatt dBm Since dBm represents a power level you will need to know the signal s RMS voltage and the load res
253. ps Chapter 3 Features and Functions Pulse Waveforms e Front Panel Operation After selecting the pulse function press the Freq softkey again to toggle to the Period softkey Then use the knob or numeric keypad to enter the desired pulse period e Remote Interface Operation PULSe PERiod lt seconds gt MINimum MAXimum Pulse Width The pulse width represents the time from the 50 threshold of the rising edge of the pulse to the 50 threshold of the next falling edge e Pulse width 8 ns to 2000 seconds see restrictions below The default pulse width is 100 ps e The specified pulse width must be less than the difference between the period and the edge time as shown below The function generator will automatically adjust the pulse width as needed to accommodate the specified period Pulse Width lt Period 1 6 X Edge Time e The pulse width must also be greater than the total time of one edge as shown below Pulse Width gt 1 6 X Edge Time e Front Panel Operation After selecting the pulse function press the Pulse Width softkey Then use the knob or numeric keypad to enter the desired pulse width e Remote Interface Operation PULSe WIDTh lt seconds gt MINimum MAXimum 65 Chapter 3 Features and Functions Pulse Waveforms Edge Time The edge time represents the time from the 10 threshold to the 90 threshold of both the rising and falling edges e Edge time 5 ns to 1 ms see restr
254. pter 4 Remote Interface Reference Frequency Sweep Commands MARKer FREQuency lt requency gt MINimum MAXimum MARKer FREQuency MINimum MAXimum Set the marker frequency This is the frequency at which the signal on the front panel Sync connector goes to a logic low during the sweep The Sync signal always goes from low to high at the beginning of the sweep Select from 1 uHz to 80 MHz limited to 1 MHz for ramps and 25 MHz for arbitrary waveforms The default is 500 Hz MIN 1 uHz MAX the start frequency or stop frequency whichever is higher The FREQ query returns the marker frequency in hertz e When sweep is enabled the marker frequency must be between the specified start frequency and stop frequency If you attempt to set the marker frequency to a frequency not in this range the function generator will automatically set the marker frequency equal to the start frequency or stop frequency whichever is closer From the remote interface a Settings conflict error will be generated and the marker frequency will be adjusted as described MARKer OFF ON MARKer Disable or enable the frequency marker When the frequency marker is disabled the signal output from the Sync connector is the normal Sync signal for the carrier waveform see Sync Output Signal on page 62 The default is OFF The MARK query returns 0 OFF or 1 ON e The OUTP SYNC command is overridden by the setting of the MARK
255. r e Braces enclose the parameter choices for a given command string The braces are not sent with the command string e A vertical bar separates multiple parameter choices for a given command string e Triangle brackets lt gt indicate that you must specify a value for the enclosed parameter For example the above syntax statement shows the frequency parameter enclosed in triangle brackets The brackets are not sent with the command string You must specify a value for the parameter such as FREQ 5000 e Some parameters are enclosed in square brackets The square brackets indicate that the parameter is optional and can be omitted The brackets are not sent with the command string If you do not specify a value for an optional parameter the function generator chooses a default value 242 Chapter 4 Remote Interface Reference An Introduction to the SCPI Language Command Separators A colon is used to separate a command keyword from a lower level keyword You must insert a blank space to separate a parameter from a command keyword If a command requires more than one parameter you must separate adjacent parameters using a comma as shown below APPL SIN 5 KHZ 3 0 VPP 2 5 V A semicolon is used to separate commands within the same subsystem and can also minimize typing For example sending the following command string PREQ START 10 STOP 1
256. r modulation mode is turned off 183 Chapter 4 Remote Interface Reference Frequency Sweep Commands TRIGger SOURce IMMediate EXTernal BUS TRIGger SOURce Select the source from which the function generator will accept a trigger The function generator will accept an immediate internal trigger a hardware trigger from the rear panel Trig In connector or a software bus trigger The default is IMM The SOUR query returns IMM EXT or BUS e When the Immediate internal source is selected the function generator outputs a continuous sweep at a rate determined by the sweep time specified SWE TIME command e When the External source is selected the function generator will accept a hardware trigger applied to the rear panel Trig In connector The function generator initiates one sweep each time Trig In receives a TTL pulse with the edge polarity specified by the TRIG SLOP command see page 185 Note that the trigger period must be greater than or equal to the specified sweep time plus 1 ms e When the Bus software source is selected the function generator initiates one sweep each time a bus trigger command is received To trigger the function generator from the remote interface either GPIB or RS 232 send the TRIG or TRG trigger command The front panel key is illuminated when the function generator is waiting for a bus trigger e The APPLy command automatically sets the trigger
257. r than the carrier frequency with FM enabled the function generator will automatically adjust the deviation to the maximum value allowed with the present carrier frequency e The sum of the carrier frequency and deviation must be less than or equal to the maximum frequency for the selected function plus 100 kHz 80 1 MHz for sine and square 1 1 MHz for ramp and 25 1 MHz for arbitrary waveforms If you attempt to set the deviation to a value that is not valid the function generator will automatically adjust it to the maximum value allowed with the present carrier frequency e Front Panel Operation To set the carrier frequency press the Freq softkey for the selected function Then use the knob or numeric keypad to enter the desired frequency e Remote Interface Operation FREQuency lt frequency gt MINimum MAXimum You can also use the APPLy command to select the function frequency amplitude and offset with a single command 74 Chapter 3 Features and Functions Frequency Modulation FM Modulating Waveform Shape The function generator will accept an internal or external modulation source for FM Modulating waveform shape internal source Sine Square Ramp Negative Ramp Triangle Noise or Arb waveform The default is Sine e Square has 50 duty cycle e Ramp has 100 symmetry Be e Triangle has 50 symmetry yes e Negative ramp has 0 symmetry You can use noise as the modulating waveshape but
258. range burst period limited by length of burst value clipped to upper limit It is not possible to specify a burst period which is too short for the function generator to output with the specified burst count and frequency see below If the burst period is too short the function generator will automatically adjust it as needed to continuously re trigger the burst Burst Count M 200 ns Waveform Frequency Burst Period gt Data out of range burst count limited by length of burst value clipped to lower limit If the Immediate trigger source is selected TRIG SOUR IMM command the burst count must be less than the product of the burst period and the waveform frequency as shown below Burst Count lt Burst Period X Waveform Frequency Data out of range amplitude value clipped to This generic message indicates that the waveform amplitude has been limited to an upper or lower boundary Data out of range offset value clipped to This generic message indicates that the offset voltage has been limited to an upper or lower boundary Data out of range frequency in burst mode value clipped to This generic message indicates that the frequency has been limited to an upper or lower boundary as dictated by the burst period Data out of range frequency in FM value clipped to This generic message indicates that the carrier frequency has been limited to a lower boundary as determined by the FM DE
259. rb waveform error is generated You cannot delete any of the five built in arbitrary waveforms If you attempt to delete one of these waveforms a Not able to delete a built in arb waveform error is generated 207 Chapter 4 Remote Interface Reference Arbitrary Waveform Commands DATA ATTRibute AVERage lt arb name gt Query the arithmetic average of all data points for the specified arbitrary waveform 1 lt average lt 1 The default arb name is the arbitrary waveform currently active selected with FUNC USER command e Ifyou query a waveform that is not currently stored in memory a Specified arb waveform does not exist error is generated DATA ATTRibute CFACtor lt arb name gt Query the crest factor of all data points for the specified arbitrary waveform Crest factor is the ratio of the peak value to the RMS value of the waveform The default arb name is the arbitrary waveform currently active selected with FUNC USER command e Ifyou query a waveform that is not currently stored in memory a Specified arb waveform does not exist error is generated DATA ATTRibute POINts lt arb name gt Query the number of points in the specified arbitrary waveform Returns a value from 1 to 65 536 points The default arb name is the arbitrary waveform currently active selected with FUNC USER command e Ifyou query a waveform that is not currently stored in memory a Speci
260. resent will remain unchanged when the waveform is inverted Normal Inverted N Normal Inverted YN AN A E J Pa i i a y f a Offset V ov JX 0V i A N J Nae Rae ae No Offset Voltage With Offset Voltage e When a waveform is inverted the Sync signal associated with the waveform is not inverted OUTPut SYNC OFF ON OUTPut SYNC Disable or enable the front panel Sync connector At lower amplitudes you can reduce output distortion by disabling the Sync signal The default setting is ON The SYNC query returns 0 OFF or 1 ON e For more details on the Sync signal for each waveform function see Sync Output Signal on page 62 e When the Sync signal is disabled the output level on the Sync connector is a logic low level e When a waveform is inverted OUTP POL command the Sync signal associated with the waveform is not inverted e The OUTP SYNC command is overridden by the setting of the MARK command used with the sweep mode see page 186 Therefore when the marker frequency is enabled and the sweep mode is also enabled the OUTP SYNC command is ignored 164 Chapter 4 Remote Interface Reference Output Configuration Commands VOLTage UNIT VPP VRMS DBM VOLTage UNIT Select the units for output amplitude does not affect offset voltage or high low levels The default is VPP The UNIT query returns VPP VRMS or DBM e The function g
261. rms If you attempt to set the deviation to a value that is not valid the function generator will automatically adjust it to the maximum value allowed with the present carrier frequency Settings conflict frequency forced duty cycle change If the square wave function is selected and you change to a frequency that cannot produce the current duty cycle the duty cycle is automatically adjusted to the maximum value for the new frequency For example if you currently have the duty cycle set to 70 and then change the frequency to 60 MHz the function generator will automatically adjust the duty cycle to 50 upper limit for this frequency Duty Cycle 20 to 80 frequency lt 25 MHz 40 to 60 25 MHz lt frequency lt 50 MHz 50 frequency gt 50 MHz Settings conflict selected arb is missing changing selection to default If you delete an arbitrary waveform from non volatile memory after storing the instrument state the waveform data is lost and the function generator will not output the waveform when the state is recalled The built in exponential rise waveform is output in place of the deleted waveform 259 221 221 221 221 Chapter 5 Error Messages Execution Errors Settings conflict offset changed due to amplitude The relationship between offset voltage and output amplitude is shown below Vmax is the maximum peak voltage for the selected output termination 5 volts for a 50Q load or 1
262. rom the remote interface a Settings conflict error will be generated and the amplitude will be adjusted as described Arbitrary Waveform Limitations For arbitrary waveforms the maximum amplitude will be limited if the waveform data points do not span the full range of the output DAC Digital to Analog Converter For example the built in Sinc waveform does not use the full range of values between 1 and therefore its maximum amplitude is limited to 6 087 Vpp into 50 ohms While changing amplitude you may notice a momentary disruption in the output waveform at certain voltages due to switching of the output attenuators The amplitude is controlled however so the output voltage will never exceed the current setting while switching ranges To prevent this disruption in the output you can disable the voltage autoranging feature using the VOLT RANG AUTO command see page 160 for more information You can also set the amplitude with an associated offset voltage by specifying a high level and low level For example if you set the high level to 2 volts and the low level to 3 volts the resulting amplitude is 5 Vpp with an associated offset voltage of 500 mV See the VOLT HIGH and VOLT LOW commands on page 159 for more information To output a dc voltage level select the de voltage function using the FUNC DC command and then set the offset voltage level using the VOLT OFFS command You can set the dc level to any
263. rrors Self Test Errors The following errors indicate failures that may occur during a self test Refer to the Agilent 33250A Service Guide for more information 601 Self test failed system logic This error indicates that the main CPU U202 cannot communicate with the main logic FPGA U302 602 Self test failed dsp This error indicates that the main CPU U202 cannot communicate with the DSP U506 603 Self test failed waveform logic This error indicates that the main CPU U202 cannot communicate with the waveform logic FPGA U1201 604 Self test failed even waveform memory bank This error indicates that either the even waveform memory U1304 or the waveform logic FPGA circuitry U1301 U1302 U1306 has failed 605 Self test failed odd waveform memory bank This error indicates that either the odd waveform memory U1305 or the waveform logic FPGA circuitry U1302 U1303 U1307 has failed 606 Self test failed cross isolation interface This error indicates that the I O processor U105 has either timed out or failed its self test 607 to 614 607 Self test failed ground 608 Self test failed 16V supply 609 Self test failed 12V supply 610 Self test failed 5V supply 611 Self test failed 3 3V supply 612 Self test failed 2 1V supply 613 Self test failed 5 2V supply 614 Self test failed 16V supply These errors indicate that the internal ADC has detected a power supply with a voltag
264. ry corruption detected The non volatile memory used to store instrument states has detected a checksum error This error may be the result of a device failure or extreme conditions such as lightning or strong magnetic fields Configuration memory lost memory corruption detected The non volatile memory used to store the function generator s configuration settings i e remote interface settings has detected a checksum error This error may be the result of a device failure or extreme conditions such as lightning or strong magnetic fields 265 350 361 362 363 Chapter 5 Error Messages Execution Errors Queue overflow The error queue is full because more than 20 errors have occurred No additional errors are stored until you remove errors from the queue The error queue is cleared by the CLS clear status command or when the power is cycled The errors are also cleared when you read the queue The error queue is not cleared by an instrument reset RST command Parity error in program message This error is most likely to occur when the function generator s parity setting RS 232 interface does not match the computer s parity setting This error may also occur in the presence of noise on the RS 232 cable Framing error in program message This error is most likely to occur when the number of stop bits for the computer RS 232 interface does not match the function generator s setting fixed at 1 st
265. s 3 30 00 d rivate Sub cmdStart_Click Dim i As Integer Used as general purpose counter cmdStart Enabled False Disable Start button Return the 33250A to turn ON conditions Arb I0 Output Arb I0 Output xRSOT r CLS r Default state of instrument Clear errors and status Continued 282 Chapter 6 Application Programs Example Microsoft Visual Basic for Windows AM Modulation Arb Output OUTPut LOAD INFinity E Arb Output APPLy SINusoid 1e6 1 0 K Arb Output AM INTernal FUNCtion RAMP 7 Arb Output AM INTernal FREQuency 10e3 Arb Output AM DEPTh 80 d Arb Output AM STATe ON d Check_Errors z MsgBox AM Modulation vbOKOnly 33250A Arb Output AM STATe OFF i T FM Modulation id Arb Output outp load 50 4 Arb Output appl sin 20e3 1 0 r Arb Output fm dev 20e3 Arb Output fm int freq 1000 d Arb Output fm stat on Check_Errors z MsgBox FM Modulation vbOKOnly 33250A r Arb Output fm stat off Linear Sweep Arb Output sweep time 1 Arb Output freq start 100 7 Arb Output freq stop 20000 d Arb Output sweep stat on r Check_Errors MsgBox Linear Sweep vbOKOnly Arb Output sweep stat off d J Pulse Waveform with variable Edge Times Arb Output output state off d Arb Output volt low 0 volt high 0 75 7 Arb Output pulse period le 3 7 Arb
266. s as an error in the load voltage However since the instrument is isolated there is a high series impedance typically 1 MQ in parallel 45 nF in the path to oppose the flow of Ignp and thereby minimize this effect 305 Chapter 7 Tutorial Ground Loops Agilent 33250A l Z Z Vout Snieg Ri lt Vi Vout lenn X Zshieta PNG bi lt lt SiMe ii Ienn fo ry ON Net Vann Ground Loop Effects At frequencies above a few kilohertz a coaxial cable s shield becomes inductive rather than resistive and the cable acts as a transformer When this happens it tends to force the shield and center conductor currents to be equal but opposite For any voltage drop in the shield due to Ignp there is a similar drop in the center conductor This is known as the balun effect and it reduces ground loops at higher frequencies Note that lower shield resistance causes the balun effect to become more of a factor at lower frequencies Therefore coaxial cables with two or three braided shields are much better than those with single braids To reduce errors due to ground loops connect the function generator to the load using a high quality coaxial cable and ground it at the load through the cable s shield If possible make sure the function generator and the load are connected to the same electrical outlet to minimize further differences in ground
267. sable the Sync connector e By default the Sync signal is routed to the Sync connector enabled When the Sync signal is disabled the output level on the Sync connector is at a logic low level e When a waveform is inverted see Waveform Polarity on the previous page the Sync signal associated with the waveform is not inverted e The Sync signal setting is overridden by the setting of the Marker frequency used with the sweep mode see page 86 Therefore when the marker frequency is enabled and the sweep mode is also enabled the Sync signal setting is ignored e For sine ramp and pulse waveforms the Sync signal is a square waveform with a 50 duty cycle The Sync signal is a TTL high when the waveform s output is positive relative to zero volts or the dc offset value The Sync signal is a TTL low when the output is negative relative to zero volts or the dc offset value e For square waveforms the Sync signal is a square waveform with the same duty cycle as the main output The Sync signal is a TTL high when the waveform s output is positive relative to zero volts or the dc offset value The Sync signal is a TTL low when the output is negative relative to zero volts or the dc offset value e For arbitrary waveforms the Sync signal is a square waveform with a 50 duty cycle The Sync signal is a TTL high when the first downloaded waveform point is output e For intern
268. se variations in the function generator The calibration procedures for the 33250A provide all of the information necessary to calculate the proper DAC values see the Agilent 33250A Service Guide Two attenuators 10 dB and 20 dB and an amplifier 20 dB are used in various combinations to control the output amplitude in 10 dB steps over a wide range of amplitude values 1 mVpp to 10 Vpp Waveform Anti Aliasing B Output DAC Filter Multiplier Attenuators Amplifier KS in 0 dB or OdBor OdBor N main OY 2 1008 20dB 7 4200B Output Amplitude DAC FEN DC Offset Ky DAC Flatness AM Sey DAC ye Note that the dc offset is summed with the ac signal after the attenuator stages but before the output amplifier This allows relatively small ac signals to be offset by relatively large dc voltages For example you can offset a 100 mVpp signal by almost 5 Vdc into a 50 load When changing ranges the 33250A always switches attenuators such that the output voltage never exceeds the current amplitude setting However momentary disruptions or glitches caused by switching can cause problems in some applications For this reason the 33250A incorporates a range hold feature to freeze the attenuator and amplifier switches in their current states However the amplitude and offset accuracy and resolution as well as waveform fidelity may be adversely affected when redu
269. sents amplitude values by 4 096 discrete voltage levels or 12 bit vertical resolution The specified waveform data is divided into samples such that one waveform cycle exactly fills waveform memory see the illustration below for a sine wave If you create an arbitrary waveform that does not contain exactly 16K or 64K points the waveform is automatically stretched by repeating points or by interpolating between existing points as needed to fill waveform memory Since all of waveform memory is filled with one waveform cycle each memory location corresponds to a phase angle of 27 16 384 radians or 27 65 536 radians 2047 me fe 8192 16383 180 360 DAC f Memory Address net 4096 12288 Phase 909 2709 2048 aes Sine Wave Representation in Waveform Memory Direct digital synthesis DDS generators use a phase accumulation technique to control waveform memory addressing Instead of using a counter to generate sequential memory addresses an adder is used see the following page On each clock cycle the constant loaded into the phase increment register PIR is added to the present result in the phase accumulator The most significant bits of the phase accumulator output are used to address waveform memory By changing the PIR constant the number of clock cycles required to step through the entire waveform memory changes thus changing the output frequency When a new PIR constant is loaded into th
270. sine wave At this point the function generator outputs an AM waveform with the specified modulation parameters if the output is enabled 6 View the waveform h 2 f of 2 60 0 n AN Eaa Type Eu i UV Ven VN 3 To turn off the Graph Mode press amp 35 Chapter 2 Front Panel Menu Operation To Output an FSK Waveform To Output an FSK Waveform You can configure the function generator to shift its output frequency between two preset values using FSK modulation The rate at which the output shifts between the two frequencies called the carrier frequency and the hop frequency is determined by the internal rate generator or the signal level on the rear panel Trig In connector For this example you will set the carrier frequency to 3 kHz and the hop frequency to 500 Hz with an FSK rate of 100 Hz a pa ae 1 Select the function frequency and amplitude of the carrier Sine and then press the Freq Ampl and Offset softkeys to configure the carrier waveform For this example select a 3 kHz sine wave with an amplitude of 5 Vpp 2 Select FSK c and then select FSK using the Type softkey Notice that a status message FSK is shown in the upper left corner of the display 36 Chapter 2 Front Panel Menu Operation To Output an FSK Waveform 3 Set the hop frequency Press the Hop Freq softkey and then
271. source the modulated waveform is generated by a DDS process running in an internal digital signal processor DSP If you select the external source the modulated waveform is controlled by the signal level present on the function generator s rear panel Modulation In connector The external signal is sampled and digitized by an analog to digital converter ADC and is then routed to the DSP With either modulation source the result is a stream of digital samples representing the modulating waveform Note that for FSK the output frequency is determined by the signal level present on the rear panel Trig In connector 309 Chapter 7 Tutorial Modulation Amplitude Modulation AM For AM the DSP routes modulation samples to a digital to analog converter DAC which then controls the output amplitude via an analog multiplier The DAC and multiplier are the same as those used to set the function generator s output level see Output Amplitude Control on page 304 This form of AM is called double sideband transmitted carrier and is the type of modulation used by most AM radio stations Modulating Signal Vetetetefetetetetefeteteteteftetetetepetetetetptetetetptetetetefetetetetefetetetete preter Modulated Carrier 100 depth shown Amplitude Modulation The amount of amplitude modulation is called the modulation depth which refers to the portion of the amplitude range that will be used by t
272. source to Immediate equivalent to TRIG SOUR IMM command e To ensure synchronization when the Bus source is selected send the WAL wait command When the WAI command is executed the function generator waits for all pending operations to complete before executing any additional commands For example the following command string guarantees that the first trigger is accepted and the operation is executed before the second trigger is recognized TRIG SOUR BUS TRG WAI TRG WAI e You can use the OPC operation complete query command or the OPC operation complete command to signal when the sweep is complete The OPC command returns 1 to the output buffer when the sweep is complete The OPC command sets the Operation Complete bit bit 0 in the Standard Event register when the sweep is complete 184 Chapter 4 Remote Interface Reference Frequency Sweep Commands TRIGger SLOPe POSitive NEGative TRIGger SLOPe Select whether the function generator uses the rising edge or falling edge of the trigger signal on the rear panel Trig In connector for an externally triggered sweep The default is POS rising edge The SLOP query returns POS or NEG OUTPut TRIGger SLOPe POSitive NEGative OUTPut TRIGger SLOPe Select a rising or falling edge for the trigger out signal When enabled using the OUTP TRIG command see below a TTL compatible square waveform with the specified
273. st to describe and observe in the frequency domain using a spectrum analyzer Any component of the output signal which has a different frequency than the fundamental or carrier is considered to be spurious The signal imperfections can be categorized as harmonic non harmonic or phase noise and are specified in decibels relative to the carrier level or dBc Harmonic Imperfections Harmonic components always appear at multiples of the fundamental frequency and are created by non linearities in the waveform DAC and other elements of the signal path The 33250A uses a 100 MHz low pass filter to attenuate very high frequency harmonics At lower frequencies and low amplitudes another possible source of harmonic distortion is due to the current flowing through the cable connected to the function generator s Sync output connector This current can cause a small square wave voltage drop across the resistance of the cable s shield and some of this voltage can be imposed on the main signal If this is a concern for your application you should remove the cable or disable the Sync output connector If your application requires that you use the Sync output connector you can minimize the effect by terminating the cable in a high impedance load rather than into a 500 load Non Harmonic Imperfections The biggest source of non harmonic spurious components called spurs is the waveform DAC Nonlinearity in the DAC leads to harmo
274. state The function frequency amplitude and offset are returned as shown in the sample string below the quotation marks are returned as part of the string SIN 5 0000000000000E 03 3 0000000000000E 00 2 5000000000000E 00 152 Chapter 4 Remote Interface Reference Output Configuration Commands Output Configuration Commands See also Output Configuration starting on page 49 in chapter 3 This section describes the low level commands used to program the function generator Although the APPLy command provides the most straightforward method to program the function generator the low level commands give you more flexibility to change individual parameters FUNCtion SINusoid SQUare RAMP PULSe NOISe DC USER FUNCtion Select the output function The selected waveform is output using the previously selected frequency amplitude and offset voltage settings The default is SIN The FUNC query returns SIN SQU RAMP PULS NOIS DC or USER e Ifyou select USER the function generator outputs the arbitrary waveform currently selected by the FUNC USER command e The table below shows which output functions are allowed with modulation sweep and burst Each indicates a valid combination If you change to a function that is not allowed with modulation sweep or burst the modulation or mode is turned off Sine Square Ramp Pulse
275. system is designed to provide context sensitive assistance on any front panel key or menu softkey A list of help topics is also available to assist you with several front panel operations View the help information for a function key Press and hold down the key If the message contains more information than will fit on the display press the 4 softkey or turn the knob clockwise to view the remaining information idal waveform ct DC On DONE Press DONE to exit the help menu View the help information for a menu softkey Press and hold down the Freq softkey If the message contains more information than will fit on the display press the 4 softkey or rotate the knob clockwise to view the remaining information DONE Press DONE to exit the help menu 25 Chapter 1 Quick Start To Use the Built In Help System 3 View the list of help topics eP key to view the list of available help topics To scroll through the list press the T or J softkey or rotate the knob Select the third topic Get HELP on any key and then press SELECT DONE Press DONE to exit the help menu 4 View the help information for displayed messages Whenever a limit is exceeded or any other invalid configuration is found the function generator will display a message For example if you enter a value that exceeds the frequency limit for the selected function a message will be displayed The built in help system pr
276. t Applicable Arbs 1 wHz 25 MHz e Limits Due to Function The frequency limits are determined by the function specified in the APPLy command For example if you are currently outputting an 80 MHz sine wave and then change to the ramp function using the APPLy command the function generator will automatically adjust the output frequency to 1 MHz the upper limit for ramps From the remote interface a Data out of range error will be generated and the frequency will be adjusted as described 145 Chapter 4 Remote Interface Reference Using the APPLy Command Output Amplitude For the amplitude parameter of the APPLy command the output amplitude range depends on the function specified and the output termination You can substitute MINimum MAXimum or DEF ault in place of a specific value for the amplitude parameter MIN selects the smallest amplitude 1 mVpp into 50 ohms MAX selects the largest amplitude for the function specified at most 10 Vpp into 50 ohms depending on function and offset voltage The default amplitude is 100 mVpp into 50 ohms for all functions Limits Due to Output Termination The output amplitude limits are determined by the current output termination setting the APPLy command does not change the termination setting For example if you set the amplitude to 10 Vpp and then change the output termination from 50 ohms to high impedance the amplitude display
277. t of 25 MHz However note that the useful upper limit is usually less due to the function generator s bandwidth limitation and aliasing Waveform components above the function generator s 3 dB bandwidth will be attenuated For example consider an arbitrary waveform consisting of 10 cycles of a sine waveform When you set the output frequency to 5 MHz the actual output frequency will be 50 MHz and the amplitude will be attenuated by 3 dB As you increase the frequency above 5 MHz more attenuation will occur At approximately 8 MHz waveform distortion due to aliasing will become evident Some aliasing will be present in most arbitrary waveforms but whether or not it will be troublesome depends on your specific application When creating arbitrary waveforms the function generator will always attempt to replicate the finite length time record to produce a periodic version of the data in waveform memory However as shown on the following page it is possible that the shape and phase of a signal may be such that a discontinuity is introduced at the end point When the waveshape is repeated for all time this end point discontinuity will introduce leakage errors in the frequency domain because many spectral terms are required to describe the discontinuity 298 Chapter 7 Tutorial Creating Arbitrary Waveforms Leakage error is caused when the waveform record does not include an integral number of cycles of the fundamental frequency Pow
278. t panel menus The remainder of this chapter contains examples of using the front panel menus Configure the modulation parameters for AM FM and FSK e Select the modulation type e Select an internal or external modulation source e Specify the AM modulation depth modulating frequency and modulation shape e Specify the FM frequency deviation modulating frequency and modulation shape e Specify the FSK hop frequency and FSK rate Configure the parameters for frequency sweep e Select linear or logarithmic sweeping Select the start stop frequencies or center span frequencies e Select the time in seconds required to complete a sweep e Specify a marker frequency Specify an internal or external trigger source for the sweep e Specify the slope rising or falling edge for an external trigger source e Specify the slope rising or falling edge of the Trig Out signal Configure the parameters for burst e Select the triggered N Cycle or externally gated burst mode e Select the number of cycles per burst 1 to 1 000 000 or Infinite e Select the starting phase angle of the burst 360 to 360 e Specify the time from the start of one burst to the start of the next burst e Specify a delay between the trigger and the start of the burst e Specify an internal or external trigger source for the burst e Specify the slope rising or falling edge for an external trigg
279. t waveform cycle is completed and then the function generator stops while remaining at the voltage level corresponding to the starting burst phase of the selected waveform Burst Mode BURS MODE Burst Count BURS NCYC Burst Period BURS INT PER Burst Phase BURS PHAS Trigger Source TRIG SOUR Triggered Burst Mode Internal Trigger TRIGgered Available Available Available IMMediate Triggered Burst Mode i External Trigger TRIGgered Available Not Used Available EXTernal BUS Gated Burst Mode GATed Not Used Not Used Available Not Used External Trigger 187 Chapter 4 Remote Interface Reference Burst Mode Commands Configure the burst waveform Use the APPLy command or the equivalent FUNC FREQ VOLT and VOLT OFFS commands to select the function frequency amplitude and offset of the waveform You can select a sine square ramp pulse or arbitrary waveform noise is allowed only in the gated burst mode and dc is not allowed For internally triggered bursts the minimum frequency is 2 mHz For sine and square waveforms frequencies above 25 MHz are allowed only with an infinite burst count Select the triggered or gated burst mode Select the triggered burst mode or external gated burst mode using the BURS MODE command Set the burst count Set the burst count the number of cycles per burst to any value between 1 and 1 000 000 cycles or in
280. ta Register The Questionable Data register group provides information about the quality or integrity of the function generator Any or all of these conditions can be reported to the Questionable Data summary bit through the enable register To set the enable register mask you must write a decimal value to the register using the STAT QUES ENABle command Bit Definitions Questionable Data Register Decimal Bit Number Value Definition 0 Voltage Overload 1 Voltage overload on OUTPUT connector The Output has been disabled 1 Not Used 2 Not Used Returns 0 2 Not Used 4 Not Used Returns 0 3 Not Used 8 Not Used Returns 0 4 Over Temperature 16 Internal temperature is too high and a power shutdown is likely 5 Loop Unlocked 32 Function generator has lost phase lock Frequency accuracy will be affected 6 Not Used 64 Not Used Returns 0 7 External Mod Overload 128 Voltage overload on MOD IN connector 8 Calibration Error 256 Error occurred during cal or cal memory lost or calibration is unsecured 9 External Reference 512 External timebase is being used 10 Not Used 1024 Not Used Returns 0 11 Not Used 2048 Not Used Returns 0 12 Not Used 4096 Not Used Returns 0 13 Not Used 8192 Not Used Returns 0 14 Not Used 16384 Not Used Returns 0 15 Not Used 32768 Not Used Returns 0 231 Chapter 4 Remote Interface Refer
281. ter the specified number of cycles have been output the function generator stops and waits for the next trigger At power on the internally triggered burst mode is enabled e Burst trigger source Internal External or Manual The default is Internal e When the Internal immediate source is selected the frequency at which the burst is generated is determined by the burst period e When the External source is selected the function generator will accept a hardware trigger applied to the rear panel Trig In connector The function generator outputs the specified number of cycles each time Trig In receives a TTL pulse with the specified polarity External trigger signals that occur during a burst are ignored e When the Manual source is selected the function generator outputs one burst each time the front panel key is pressed e When the External or Manual trigger source is selected the burst count and burst phase remain in effect but the burst period is ignored e You can insert a time delay between the receipt of the trigger and the start of the burst waveform used in triggered burst mode only e Front Panel Operation Press the Trigger Setup softkey and then select the desired source by pressing the Source softkey To insert a trigger delay press the Delay softkey used in the triggered burst mode only To specify whether the function generator triggers on the rising or falling edge of the signal on the Trig In connector
282. ters can be letters numbers 0 9 or the underscore character _ Blank spaces are not allowed An error will be generated if you specify a name with more than 12 characters e The function generator will not prevent you from assigning the same custom name to different storage locations For example you can assign the same name to locations 1 and 2 e Ifyou delete an arbitrary waveform from non volatile memory after storing the instrument state the waveform data is lost and the function generator will not output the waveform when the state is recalled The built in exponential rise waveform is output in place of the deleted waveform e The front panel display state see Display Control on page 115 is saved when you store the instrument state When you recall the state the front panel display will return to the previous state e An instrument reset does not affect the configurations stored in memory Once a state is stored it remains until it is overwritten or specifically deleted 110 Chapter 3 Features and Functions System Related Operations Front Panel Operation Press and then select the Store State or Recall State softkey To delete a stored state select the Delete State softkey also removes the custom name for this memory location To configure the function generator to recall the factory default state at power on press and then select the Pwr On Default softkey To configure th
283. the display Set the start frequency Press the Start softkey and then set the value to 50 Hz using the numeric keypad or the knob and arrow keys Internal Trigger ot 000 000 Hz WV 4 Loy i are 38 Chapter 2 Front Panel Menu Operation To Output a Frequency Sweep Set the stop frequency Press the Stop softkey and then set the value to 5 kHz using the numeric keypad or the knob and arrow keys IE Internal Trigger gez 500 000 00 kHz VY Ft Sweep Marker Trigger a Span Time OFF Setup At this point the function generator outputs a continuous sweep from 50 Hz to 5 kHz if the output is enabled Note If desired you can set the frequency boundaries of the sweep using a center frequency and frequency span These parameters are similar to the start frequency and stop frequency and are included to give you added flexibility To achieve the same results set the center frequency to 2 525 kHz and the frequency span to 4 950 kHz View the waveform For more information see To Trigger a Sweep or Burst on page 42 39 Chapter 2 Front Panel Menu Operation To Output a Burst Waveform To Output a Burst Waveform You can configure the function generator to output a waveform with a specified number of cycles called a burst You can output the burst at a rate determined by the internal rate generator or the signal level on the rear panel Trig In connector For this example
284. tically adjust the duty cycle to 50 the upper limit for this frequency e Ifyou select a square waveform as the modulating waveform for AM or FM the duty cycle setting does not apply The function generator always uses a square waveform with a 50 duty cycle e Front Panel Operation After selecting the square wave function press the Duty Cycle softkey Then use the knob or numeric keypad to enter the desired duty cycle e Remote Interface Operation FUNCtion SQUare DCYCle lt percent gt MINimum MAXimum The APPLy command automatically sets the duty cycle to 50 58 Chapter 3 Features and Functions Output Configuration Symmetry Applies to ramp waves only Symmetry represents the amount of time per cycle that the ramp wave is rising assuming that the waveform polarity is not reversed 0 Symmetry 100 Symmetry e The symmetry is stored in volatile memory the symmetry is set to 100 when power has been off or after a remote interface reset e The symmetry setting is remembered when you change from ramp wave to another function When you return to the ramp function the previous symmetry is used e Ifyou select a ramp waveform as the modulating waveform for AM or FM the symmetry setting does not apply e Front Panel Operation After selecting the ramp function press the Symmetry softkey Then use the knob or numeric keypad to enter the desired symmetry e Remote Interface Operation FUNCtion RAMP SYMMetry
285. tion press CONTinue 510 520 OUTPUT Fgen OUTPut LOAD INFinity Configure for Hi Z load 530 OUTPUT Fgen APPLy SINusoid 1e6 1 0 1MHz Sine 1Vpp OVdc Offset 540 OUTPUT Fgen AM INTernal FUNCtion RAMP Modulating signal Ramp 550 OUTPUT Fgen AM INTernal FREQuency 10e3 Modulating frequency 10kHz 560 OUTPUT Fgen AM DEPTh 80 Modulating depth 80 570 OUTPUT Fgen AM STATe ON Turn ON AM modulation 580 Check_errors Routine checks for errors 590 PAUSE 600 OUTPUT Fgen am stat off Turn OFF AM modulation 610 l 620 PRINT FM Modulation press CONTinue 630 640 OUTPUT Fgen outp load 50 Configure for 50 ohm load 650 OUTPUT Fgen appl sin 20e3 1 0 20kHz Sine 1Vpp OVdc Offset 660 OUTPUT Fgen fm dev 2063 FM deviation 20kHz 670 OUTPUT Fgen fm int freq 1000 FM Modulating Freq 1kHz 680 OUTPUT Fgen fm stat on Turn ON FM modulation 690 Check_errors Routine checks for errors 700 PAUSE 710 OUTPUT Fgen fm stat off Turn OFF FM modulation 720 730 PRINT Linear Sweep press CONTinue 740 l 750 OUTPUT Fgen sweep time 1 1 second sweep time 760 OUTPUT Fgen freq start 100 Start frequency 100Hz 770 OUTPUT Fgen freq stop 20000 Stop frequency 20kHz 780 OUTPUT Fgen sweep stat on Turn ON sweeping 790 Check_errors Routine checks for errors 800 PAUSE 810 OUTPUT Fgen sweep stat off Turn OFF sweeping 820 l 830 PRINT Pulse Waveform with variable Edge Times
286. tion Overview To Change the Security Code To change the security code you must first unsecure the function generator and then enter a new code Make sure you have read the security code rules described on page 123 before attempting to change the security code e Front Panel Operation To change the security code unsecure the function generator using the old security code Then press wily select the Secure Code softkey from the Test Cal menu Changing the code from the front panel also changes the security code as seen from the remote interface e Remote Interface Operation To change the security code you must first unsecure the function generator using the old security code Then enter the new code as shown below CAL SECURE STATE OFF AT33250A Unsecure with old code CAL SECURE CODE SN123456789 Enter new code Calibration Count You can query the function generator to determine how many calibrations have been performed Note that your function generator was calibrated before it left the factory When you receive your function generator be sure to read the count to determine its initial value e The calibration count is stored in non volatile memory and does not change when power has been off or after a remote interface reset e The calibration count increments up to a maximum of 65 535 after which it rolls over to 0 Since the value increments by one for each calibration point a compl
287. tion of the SOURce subsystem is shown below to illustrate the tree system SOURce FREQuency STARt lt frequency gt MINimum MAXimum STARt MINimum MAXimum FREQuency STOP lt frequency gt MINimum MAXimum STOP MINimum MAXimum SWEep SPACing LINear LOGarithmic SPACing SWEep IME lt seconds gt MINimum MAXimum IME MINimum MAXimum SWEep STATe OFF ON STATe SOURce is the root keyword of the command FREQuency and SWEep are second level keywords and STARt and STOP are third level keywords A colon separates a command keyword from a lower level keyword 241 Chapter 4 Remote Interface Reference An Introduction to the SCPI Language Command Format Used in This Manual The format used to show commands in this manual is illustrated below FREQuency lt frequency gt MINimum MAXimum The command syntax shows most commands and some parameters as a mixture of upper and lower case letters The upper case letters indicate the abbreviated spelling for the command For shorter program lines you can send the abbreviated form For better program readability you can send the long form For example in the above syntax statement FREQ and FREQUENCY are both acceptable forms You can use upper or lower case letters Therefore FREQUENCY freq and Freq are all acceptable Other forms such as FRE and FREQUEN will generate an erro
288. top frequency Frequency Span Stop Frequency Start Frequency 182 Chapter 4 Remote Interface Reference Frequency Sweep Commands SWEep SPACing LINear LOGarithmic SWEep SPACing Select linear or logarithmic spacing for the sweep The default is Linear The SPAC query returns LIN or LOG e Fora linear sweep the function generator varies the output frequency in a linear fashion during the sweep e For a logarithmic sweep the function generator varies the output frequency in a logarithmic fashion during the sweep SWEep TIME lt seconds gt MINimum MAXimum SWEep TIME MINimum MAXimum Set the number of seconds required to sweep from the start frequency to the stop frequency Select from 1 ms to 500 seconds The default is 1 second MIN 1 ms MAX 500 seconds The TIME query returns the sweep time in seconds e The number of discrete frequency points in the sweep is automatically calculated by the function generator and is based on the sweep time that you select SWEep STATe OFF ON SWEep STATe Disable or enable the sweep mode To avoid multiple waveform changes you can enable the sweep mode after you have set up the other sweep parameters The default is OFF The STAT query returns 0 OFF or 1 ON e The function generator will not allow the sweep mode to be enabled at the same time that burst or any modulation mode is enabled When you enable sweep the burst o
289. triggered Set the marker frequency Optional If desired you can set the frequency at which the signal on the front panel Sync connector goes to a logic low during the sweep Use the MARK FRI command to set the marker frequency to any value between the start EQ frequency and stop frequency Use the MARK ON command to enable the frequency marker Enable the sweep mode After you have set up the other sweep parameters use the SWE STAT ON command to enable the sweep mode 180 Chapter 4 Remote Interface Reference Frequency Sweep Commands Sweep Commands FREQuency STARt lt requency gt MINimum MAXimum FREQuency STARt MINimum MAXimum Set the start frequency used in conjunction with the stop frequency Select from 1 uHz to 80 MHz limited to 1 MHz for ramps and 25 MHz for arbitrary waveforms The default is 100 Hz MIN 1 Hz MAX 80 MHz The STAR query returns the start frequency in hertz e To sweep up in frequency set the start frequency lt stop frequency To sweep down in frequency set the start frequency gt stop frequency FREQuency STOP lt frequency gt MINimum MAXimum FREQuency STOP MINimum MAXimum Set the stop frequency used in conjunction with the start frequency Select from 1 uHz to 80 MHz limited to 1 MHz for ramps and 25 MHz for arbitrary waveforms The default is 1 kHz MIN 1 Hz MAX 80 MHz The STOP query returns the stop frequency in hertz 1
290. trument state When you recall the instrument state the front panel display will return to the previous state e An instrument reset RST command does not affect the configurations stored in memory Once a state is stored it remains until it is overwritten or specifically deleted RCL 0 1 2 3 4 Recall the instrument state stored in the specified non volatile storage location You cannot recall the instrument state from a storage location that is empty e When shipped from the factory storage locations 1 through 4 are empty location 0 has the power on state e From the remote interface only you can use location 0 to store a fifth instrument state you cannot store to this location from the front panel However keep in mind that location 0 is automatically overwritten when power is cycled the instrument state previously stored will be overwritten 210 Chapter 4 Remote Interface Reference State Storage Commands MEMory STATe NAME 0 1 2 3 4 lt name gt MEMory STATe NAME 0 1 2 3 4 Assign a custom name to the specified storage location You can name a location from the front panel or over the remote interface but you can only recall a state by name from the front panel the RCL command requires a numeric parameter The NAME query returns a quoted string containing the name currently assigned to the specified storage location If you have not assigned a user defined name t
291. ts 1 bit fixed Number of Stop Bits 1 bit fixed To download binary data for arbitrary waveforms over the RS 232 interface you can use any handshake mode except XON XOFF and be sure to select Parity None 8 data bits You must also insert a pause of approximately 1 ms between sending the header and sending the binary block 219 Chapter 4 Remote Interface Reference RS 232 Interface Configuration RS 232 Handshake Methods You can select one of several handshake or flow control methods to coordinate the transfer of data between the function generator and your computer or modem The default handshake is DTR DSR e None In this mode data is sent and received over the interface without any flow control used When using this method use a slower baud rate lt 9600 baud and avoid sending more than 128 characters without stopping or reading a response e DTR DSR Inthis mode the function generator monitors the state of the DSR data set ready line on the RS 232 connector When the line goes true the function generator sends data over the interface When the line goes false the function generator stops sending information typically within six characters The function generator sets the DTR line false when the input buffer is almost full about 100 characters and releases the line when space is available again e Modem This mode uses the DTR DSR and RTS CTS lines to control the flow of data between the
292. ty Accessories Included EN61010 1 CSA1010 1 UL 3111 1 EN55011 IEC 61326 1 40 dBA 1 hour 1 year 3 years standard User s Guide Service Guide Quick Reference Guide Test Data Connectivity Software RS 232 Cable Power Cord This ISM device complies with Canadian ICES 001 Cet appareil ISM est conforme a la norme NMB 001 du Canada N10149 323 Chapter 8 Specifications Agilent 33250A Function Arbitrary Waveform Generator PRODUCT DIMENSIONS si eS T 254 4 mm o a 374 0 mm 348 3 mm Od ART Soo A A ooo OOO remanent ment M4 x 07 58 00 el M 4 PLACES i 19 68 219 E Ch Tn T T 2X 12 7 BY 2 6 DEEP 328 6 4X 16 j i a _ M35 X 06 A 4 PLACES a T0000 Je A A eee 49 36 All dimensions are bis shown in millimeters 324 Copyright 2000 Agilent Technologies Inc All Rights Reserved Printing History Edition 1 April 2000 New editions are complete revi sions of the manual Update packages which are issued between editions may contain additional information and replacement pages which you merge into the manual The dates on this page change only when a new edition is published Certification Agilent certifies that this prod uct met its published spec ifications at th
293. u change to a frequency that cannot produce the current duty cycle the duty cycle is automatically adjusted to the maximum value for the new frequency For example if you currently have the duty cycle set to 70 and then change the frequency to 60 MHz the function generator will automatically adjust the duty cycle to 50 the upper limit for this frequency 51 Chapter 3 Features and Functions Output Configuration Front Panel Operation To set the output frequency press the Freq softkey for the selected function Then use the knob or numeric keypad to enter the desired frequency To set the waveform period instead press the Freq softkey again to toggle to the Period softkey Remote Interface Operation FREQuency lt frequency gt MINimum MAXimum You can also use the APPLy command to select the function frequency amplitude and offset with a single command Output Amplitude The default amplitude is 100 mVpp into 50 ohms for all functions Offset Voltage Limitations The relationship between output amplitude and offset voltage is shown below Vmax is the maximum peak voltage for the selected output termination 5 volts for a 50Q load or 10 volts for a high impedance load Vpp lt 2X Vmax Voffset Limits Due to Output Termination If you change the output termination setting the displayed output amplitude will be adjusted and no error will be generated For example if you set the amplitude to 10 Vpp
294. ull frequency range The default start frequency is 100 Hz The default stop frequency is 1 kHz e To sweep up in frequency set the start frequency lt stop frequency To sweep down in frequency set the start frequency gt stop frequency e For sweeps with Marker Off the Sync signal is a square waveform with a 50 duty cycle The Sync signal is a TTL high at the beginning of the sweep and goes low at the midpoint of the sweep The frequency of the sync waveform is equal to the specified sweep time The signal is output from the front panel Sync connector e For sweeps with Marker On the Sync signal is a TTL high at the beginning of the sweep and goes low at the marker frequency The signal is output from the front panel Sync connector e Front Panel Operation After enabling sweeps press the Start or Stop softkey Then use the knob or numeric keypad to enter the desired frequency e Remote Interface Operation FREQuency STARt lt frequency gt MINimum MAXimum FREQuency STOP lt frequency gt MINimum MAXimum 83 Chapter 3 Features and Functions Frequency Sweep Center Frequency and Frequency Span If desired you can set the frequency boundaries of the sweep using a center frequency and frequency span These parameters are similar to the start frequency and stop frequency see the previous page and are included to give you added flexibility e Center frequency 1 uHz to 80 MHz limit
295. um of all bits set in the register STATus QUEStionable EVENt Query the event register in this register group This is a read only register Once a bit is set it remains set until cleared by this command or CLS clear status command A query of this register returns a decimal value which corresponds to the binary weighted sum of all bits set in the register STATus QUEStionable ENABle lt enable value gt STATus QUEStionable ENABle Enable bits in the enable register in this register group The selected bits are then reported to the Status Byte A CLS clear status will not clear the enable register but it does clear all bits in the event register The STATus PRESet command clears all bits in the enable register To enable bits in the enable register you must write a decimal value which corresponds to the binary weighted sum of the bits you wish to enable in the register The ENAB query returns a decimal value which corresponds to the binary weighted sum of all bits enabled by the STAT QUES ENAB command 236 Chapter 4 Remote Interface Reference Status Reporting Commands Standard Event Register Commands See the table on page 233 for the register bit definitions ESR Query the Standard Event Status Register Once a bit is set it remains set until cleared by a CLS clear status command or queried by this command A query of this register returns a decimal value which
296. unction generator varies the output frequency in a logarithmic fashion e Sweep mode Linear or Logarithmic The default is Linear e Front Panel Operation After enabling sweeps press the Linear softkey again to toggle between the linear or log mode e Remote Interface Operation SWEep SPACing LINear LOGarithmic Sweep Time The sweep time specifies the number of seconds required to sweep from the start frequency to the stop frequency The number of discrete frequency points i n the sweep is automatically calculated by the function generator and is based on the sweep time you select e Sweep time 1 ms to 500 seconds The default is 1 second e Front Panel Operation After enabling sweeps press the Sweep Time softkey Then use the knob or numeric keypad to enter the desired sweep time e Remote Interface Operation SWEep TIM E lt seconds gt MINimum MAXimum 85 Chapter 3 Features and Functions Frequency Sweep Marker Frequency If desired you can set the frequency at which the signal on the front panel Sync connector goes to a logic low during the sweep The Sync signal always goes from low to high at the beginning of the sweep e Marker frequency 1 uHz to 80 MHz limited to 1 MHz for ramps and 25 MHz for arbitrary waveforms The default is 500 Hz e When the sweep mode is enabled the marker frequency must be between the specified start frequency and stop frequency If you att
297. unction generator outputs a pulse gt 1 ps pulse width from the Trig Out connector at the beginning of each burst Front Panel Operation After enabling bursts press the Trigger Setup softkey Then select the desired edge by pressing the Trig Out softkey Remote Interface Operation OUTPut TRIGger SLOPe POSitive NEGative OUTPut TRIGger OFF ON 97 Chapter 3 Features and Functions Triggering Triggering Applies to sweep and burst only You can issue triggers for sweeps or bursts using internal triggering external triggering or manual triggering e Internal or automatic triggering is enabled when you turn on the function generator In this mode the function generator outputs continuously when the sweep or burst mode is selected e External triggering uses the rear panel Trig In connector to control the sweep or burst The function generator initiates one sweep or outputs one burst each time Trig In receives a TTL pulse You can select whether the function generator triggers on the rising or falling edge of the external trigger signal e Manual triggering initiates one sweep or outputs one burst each time you press from the front panel Continue pressing this key to re trigger the function generator e The key is disabled when in remote and when a function other than burst or sweep is currently selected Trigger Source Choices Applies to sweep and burst only You must specify the source
298. unction generator will automatically adjust the frequency to 25 MHz Settings conflict frequency reduced for pulse function For pulse waveforms the output frequency is limited to 50 MHz When you change to the pulse function APPL PULS or FUNC PULS command from a function that allows a higher frequency the function generator will automatically adjust the frequency to 50 MHz Settings conflict frequency reduced for ramp function For ramp waveforms the output frequency is limited to 1 MHz When you change to the ramp function APPL RAMP or FUNC RAMP command from a function that allows a higher frequency the function generator will automatically adjust the frequency to 1 MHz 254 221 221 221 221 221 221 Chapter 5 Error Messages Execution Errors Settings conflict frequency made compatible with burst mode For an internally triggered burst the output frequency is limited to a minimum of 2 mHz The function generator has adjusted the frequency to be compatible with the current settings Settings conflict frequency made compatible with FM When FM is enabled the output frequency of the carrier waveform is limited to a minimum of 5 Hz The function generator has adjusted the frequency to be compatible with the current settings Settings conflict burst turned off by selection of other mode or modulation The function generator will allow only one modulation sweep or burst mode to be ena
299. urce and you cannot copy to VOLATILE Block length must be even The function generator represents binary data as 16 bit integers which are sent as two bytes DATA DAC VOLATILE command State has not been stored The storage location that you specified in the RCL command was not used in a previous SAV command You cannot recall the instrument state from a storage location that is empty 273 274 Application Programs Application Programs This chapter contains several remote interface example programs to help you develop programs for your own application Chapter 4 Remote Interface Reference starting on page 129 lists the syntax for the SCPI Standard Commands for Programmable Instruments commands available to program the function generator Introduction Three example programs are included in this chapter and each example illustrates the same functionality in a different programming language The example programs are written in BASIC for Windows Microsoft Visual Basic for Windows and Microsoft Visual C for Windows Each example program has embedded comments to help you understand the operation of the program Each example covers the following topics related to programming the function generator e Using the short and long form of SCPI commands e Configuring an AM waveform e Configuring an FM waveform e Configuring a linear frequency sweep e Configuring a pulse w
300. urnishing performance or use of this material No part of this document may be photocopied reproduced or translated to another language without the prior written consent of Agilent Restricted Rights The Software and Documenta tion have been developed entirely at private expense They are delivered and licensed as commercial computer soft ware as defined in DFARS 252 227 7018 Oct 1988 DFARS 252 211 7015 May 1991 or DFARS 252 227 7014 Jun 1995 as a commercial item as defined in FAR 2 101 a or as restricted computer software as defined in FAR 52 227 19 Jun 1987 or any equivalent agency regulation or contract clause whichever is applicable You have only those rights pro vided for such Software and Documentation by the applica ble FAR or DFARS clause or the Agilent standard software agreement for the product involved Trademark Information Windows Windows 95 and Windows NT are registered trademarks of Microsoft Corp Safety Do not install substitute parts or perform any unauthorized modification to the product Return the product to an Agilent Sales and Service Office for service and repair to ensure that safety features are maintained Safety Symbols WARNING Calls attention to a procedure practice or condition that could possibly cause bodily injury or death CAUTION Calls attention to a procedure practice or condition that could possibly cause damage
301. urns 0 OFF or 1 ON Chapter 4 Remote Interface Reference Frequency Modulation FM Commands If the deviation causes the carrier waveform to exceed a frequency boundary for the current duty cycle square waveform only the function generator will automatically adjust the duty cycle to the maximum value allowed with the present carrier frequency From the remote interface a Settings conflict error will be generated and the duty cycle will be adjusted as described If you select the External modulating source FM SOUR EXT command the deviation is controlled by the 5V signal level present on the rear panel Modulation In connector For example if you have set the frequency deviation to 100 kHz then a 5V signal level corresponds to a 100 kHz increase in frequency Lower external signal levels produce less deviation and negative signal levels reduce the frequency below the carrier frequency The function generator will allow only one modulation mode to be enabled at a time For example you cannot enable FM and AM at the same time When you enable FM the previous modulation mode is turned off The function generator will not allow FM to be enabled at the same time that sweep or burst is enabled When you enable FM the sweep or burst mode is turned off 175 Chapter 4 Remote Interface Reference Frequency Shift Keying FSK Commands Frequency Shift Keying FSK Commands See also FSK Modulati
302. us line at the top of the display window shows the point number in yellow the time value of the current point in green and the voltage value of the current point in magenta 8 Define the first waveform point Press the Voltage softkey to set the voltage level for Point 1 this point is fixed at a time of 0 seconds By default Point 1 is set equal to the upper limit For this example set the voltage level of Point 1 to 0 V Point The waveform editor performs all amplitude calculations using Vpp rather than Vrms or dBm 105 10 Chapter 3 Features and Functions Arbitrary Waveforms Define the next waveform point Press the Point softkey and then turn the knob to move to Point 2 Press the Time softkey to set the time for the current point this softkey is not available for Point 1 Press the Voltage softkey to set the voltage level for the current point For this example set the time to 2 ms and the voltage level to 3 0 V Insert Remov Point Time oltage Point Define the remaining waveform points Using the Time and Voltage softkeys define the remaining waveform points using the values shown in the table below Point Time Value Voltage Value 1 Os OV 2 2ms 3V 3 4ms 1V 4 7ms OV e The time value of the last point that can be defined in the waveform must be less than the specified cycle period e The waveform editor automatically connects the last
303. used for sweep are listed on page 181 Select the waveform shape amplitude and offset Use the APPLy command or the equivalent FUNC FREQ VOLT and VOLT OFFS commands to select the function frequency amplitude and offset You can select a sine square ramp or arbitrary waveform pulse noise and dc are not allowed Select the frequency boundaries of the sweep You can set the frequency boundaries using one of two methods a Start Frequency Stop Frequency Use the FREQ STAR command to set the start frequency and the FREQ STOP command to set the stop frequency To sweep up in frequency set the start frequency lt stop frequency To sweep down in frequency set the start frequency gt stop frequency b Center Frequency Frequency Span Use the FREQ CENT command to set the center frequency and the FREQ SPAN command to set the frequency span To sweep up in frequency set a positive span To sweep down in frequency set a negative span Select the sweep mode Use the SWE SPAC command to select linear or logarithmic spacing for the sweep 179 Chapter 4 Remote Interface Reference Frequency Sweep Commands Set the sweep time Use the SWE TIME command to set the number of seconds required to sweep from the start frequency to the stop frequency Select the sweep trigger source Use the TRIG SOUR command to select the source from which the sweep will be
304. ut connector and press to enable the output e Front Panel Operation Press to enable or disable the output e Remote Interface Operation OUTPut OFF ON The APPLy command overrides the current setting and automatically enables the Output connector 60 Chapter 3 Features and Functions Output Configuration Waveform Polarity In the normal mode default the waveform goes positive during the first part of the cycle In the inverted mode the waveform goes negative during the first part of the cycle As shown in the examples below the waveform is inverted relative to the offset voltage Any offset voltage present will remain unchanged when the waveform is inverted Normal Inverted Normal Inverted Teg a N po ps So Su No Offset Voltage With Offset Voltage When a waveform is inverted the Sync signal associated with the waveform is not inverted Front Panel Operation Press Wility and select the Output Setup softkey Then press the Normal softkey again to toggle between the Normal and Invert selections Remote Interface Operation OUTPut POLarity NORMal INVerted 61 Chapter 3 Features and Functions Output Configuration Sync Output Signal A sync output is provided on the front panel Sync connector All of the standard output functions except de and noise have an associated Sync signal For certain applications where you may not want to output the Sync signal you can di
305. veform Press to view the waveform parameters To turn off the Graph Mode press C You can generate a single burst with the specified count by pressing the key For more information see To Trigger a Sweep or Burst on page 42 You can also use an external gate signal to either turn the output signal on or off based on the external signal applied to the rear panel Trig In connector For more information see Burst Mode on page 95 41 Chapter 2 Front Panel Menu Operation To Trigger a Sweep or Burst To Trigger a Sweep or Burst You can issue triggers from the front panel for sweeps and bursts using a manual trigger or an internal trigger Internal or automatic triggering is enabled with the default settings of the function generator In this mode the function generator outputs continuously when the sweep or burst mode is selected Manual triggering initiates one sweep or outputs one burst each time you press the key from the front panel Continue pressing this key to re trigger the function generator The key is disabled when in remote the remote icon turns on while in remote and when a function other than sweep or burst is currently selected or when the output is disabled The key flashes off momentarily when using a manual trigger 42 Chapter 2 Front Panel Menu Operation To Store the Instrument State To Store the Instrument State You can store the i
306. ware error there are no more memory locations available to store arbitrary waveforms This error is likely the result of a failed Flash memory device Cannot overwrite a built in waveform The following built in waveform names are reserved and cannot be used with the DATA COPY command EXP_RISE EXP_FALL NEG_RAMP SINC and CARDIAC Name of source arb waveform for copy must be VOLATILE When using the DATA COPY command you cannot copy from any source other than VOLATILE Specified arb waveform does not exist The DATA COPY command copies the waveform from volatile memory to the specified name in non volatile memory Before executing the DATA COPY command you must download the waveform using the DATA VOLATILE or DATA DAC VOLATILE command 272 786 787 788 800 810 Chapter 5 Error Messages Arbitrary Waveform Errors Not able to delete a built in arb waveform You cannot delete any of the five built in waveforms EXP_RISE EXP_FALL NEG_RAMP SINC and CARDIAC Not able to delete the currently selected active arb waveform You cannot delete the arbitrary waveform that is currently being output FUNC USER command Cannot copy to VOLATILE arb waveform The DATA COPY command copies the waveform from volatile memory to the specified name in non volatile memory The source for the copy is always VOLATILE You cannot copy from any other so
307. waveform point to the voltage level of first point to create a continuous waveform e To insert additional points after the current waveform point press the Insert Point softkey The new point is inserted midway between the current point and the next defined point e To remove the current waveform point press the Remove Point softkey The remaining points are joined using the interpolation method currently selected You cannot remove Point 1 since the waveform must have a defined initial value 106 Chapter 3 Features and Functions Arbitrary Waveforms 11 Store the arbitrary waveform in memory Press the End Store softkey to store the new waveform in memory Then press the DONE softkey to store the waveform in volatile memory or press the Store in Non Vol softkey to store the waveform in one of four non volatile memory locations You can assign a custom name to the four non volatile memory locations e The custom name can contain up to 12 characters The first character must be a letter but the remaining characters can be letters numbers or the underscore character _ e To add additional characters press the right arrow key until the cursor is to the right of the existing name and then turn the knob e To delete all characters to the right of the cursor press the key For this example assign the name RAMP_NEW to memory location 1 and then press the STORE ARB softkey to store the waveform _ RAMP_NEWj
308. when an error is generated from the front panel or over the remote interface You may want to disable the front panel beeper for certain applications The beeper state is stored in non volatile memory and does not change when power has been off or after a remote interface reset When shipped from the factory the beeper is enabled Turning off the beeper does not disable the key click generated when you press a front panel key or turn the knob Front Panel Operation Press Wily and then select the Beep softkey from the System menu Remote Interface Operation SYSTem BEEPer Issue a single beep immediately SYSTem BEEPer STATe OFF ON Disable enable beeper Display Bulb Saver The front panel display bulb will normally turn off and the screen will go blank after one hour of inactivity For certain applications you may want to disable the bulb saver feature This feature is available from the front panel only The bulb saver setting is stored in non volatile memory and does not change when power has been off or after a remote interface reset When shipped from the factory the bulb saver mode is enabled Front Panel Operation Press V i and then select the Sern Svr screen saver softkey from the System menu 113 Chapter 3 Features and Functions System Related Operations Display Contrast To optimize the readability of the front panel display you can adjust the contrast s
309. y NSTates Parameters shown in bold are selected following a RST reset command 138 Chapter 4 Remote Interface Reference SCPI Command Summary System Related Commands see page 213 for more information SYSTem ERRor IDN DISPlay OFF ON DISPlay DISPlay TEXT lt quoted string gt EXT EXT CLEar RST FEST SYSTem VERSion SYSTem BEEPer BEEPer STATe OFF ON BEEPer STATe LRN OPC OPC WAI Interface Configuration Commands see page 218 for more information SYSTem INTerface GPIB RS232 SYSTem LOCal SYSTem RWLock Parameters shown in bold are selected following a RST reset command 139 Chapter 4 Remote Interface Reference SCPI Command Summary Phase Lock Commands see page 223 for more information PHASe lt angle gt MINimum MAXimum PHASe MINimum MAXimum PHASe REFerence PHASe UNLock ERRor STATe OFF ON PHASe UNLock ERRor STATe IT ANGLe DEGree RADian IT ANGLe Status Reporting Commands see page 235 for more information G G STB SRE lt enable value gt SRE STATus QUEStionable CONDition QUEStionable EVENt QUEStionable ENABle lt enable value gt QUEStionable ENABle ESR ae ez N N ESE lt enable value gt ESE CLS STA
310. y set to high impedance The units are automatically converted to Vpp e Front Panel Operation Press Uiiy and select the Output Setup softkey Then use the knob or numeric keypad to select the desired load impedance or press the Load softkey again to choose High Z e Remote Interface Operation OUTPut LOAD lt ohms gt INFinity MINimum MAXimum 57 Chapter 3 Features and Functions Output Configuration Duty Cycle Applies to square waves only Duty cycle represents the amount of time per cycle that the square wave is at a high level assuming that the waveform polarity is not reversed 20 Duty Cycle 80 Duty Cycle e Duty Cycle 20 to 80 frequency lt 25 MHz 40 to 60 25 MHz lt frequency lt 50 MHz 50 frequency gt 50 MHz e The duty cycle is stored in volatile memory the duty cycle is set to 50 when power has been off or after a remote interface reset e The duty cycle setting is remembered when you change from square wave to another function When you return to the square function the previous duty cycle is used e Limits Due to Frequency If the square wave function is selected and you change to a frequency that cannot produce the current duty cycle the duty cycle is automatically adjusted to the maximum value for the new frequency For example if you currently have the duty cycle set to 70 and then change the frequency to 60 MHz the function generator will automa

Agilent 33250A User's Guide - Electrical and Computer Engineering

Contents

Download Pdf Manuals

Related Search

Related Contents