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Manual - Stanford Research Systems
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1. for i 0 i lt number i data 2 i 50 i x data 2 i 1l 8 i 1 2 1 2 y sum data 2 i data 2 i 1 add x and y to checksum data 2 number sum checksum sprintf cmd LDWF 1 d n number command to load waveform ibwrt ds345 cmd strlen cmd ibrd ds345 cmd 40 read back reply before sending data ibwrt ds345 char data long 4 number 2 number of bytes 4 per data point x and y 2 for checksum sprintf cmd FUNC5 n arb wf output r ibwrt ds345 cmd strlen cmd 3 21 HM Program Examples ee 3 22 TROUBLESHOOTING If Nothing Happens on Power On Cold Boot ERROR MESSAGES Operational Errors Message AC DC Error Arb Corrupt Arb Edit Err Arb Error Arb Fn Bad Arb Not Clr Burst Error Cntr F Error Count Error Make sure that the power entry module on the rear panel is set for the proper ac line voltage for your location that the correct fuse is installed and that the line cord is inserted all the way into the power entry module The selected line voltage may be seen through the clear window just below the fuse When the unit is plugged in and turned ON the unit s firmware version num ber and serial number will be briefly displayed The self tests should then ex ecute If the unit displays no sensible message the cold boot procedure may fix the problem To do a c
2. 3 3 EM Programming Commands ae ed and the frequency will be set to the maximum allowed for the new func tion If modulation is enabled and the current modulation parameters are in compatible with the selected function the modulation will be disabled and then the function will be set The FUNC query returns the current function l Function 0 SINE 1 SQUARE 2 TRIANGLE 3 RAMP 4 NOISE 5 ARBITRARY INVT i The INVT command turns output inversion on i 1 and off i 0 The INVT query returns the current inversion status OFFS x The OFFS command sets the output s DC offset to x volts The OFFS query returns the current value of the DC offset The DC offset voltage plus the peak AC voltage must be less than 5 Volts PCLR The PCLR command sets the waveform phase value to 0 degrees PHSE x The PHSE command sets the waveform output phase to x degrees X has 0 001 degree resolution and may range from 0 001 to 7199 999 degrees This command will produce an error if the function is set to either NOISE or ARB or if a frequency sweep FM or phase modulation is enabled The PHSE query returns the current waveform phase Modulation Control Commands note All modulation parameters may be set at any time For the changes to have an effect be sure that the modulation type is set correctly and that modulation is enabled see the MTYP and MENA commands TRG The TRG command triggers a burst or single sweep The trigger source m
3. 5 8 E Performance Tests Ml PHASE NOISE 10 000000000 MHz Frequency Standard This test measures the integrated phase noise of the DS345 s output in a 15 kHz band about carrier This test is performed at 10 MHz to minimize the contribution of discrete spurs to the measurement specification lt 50 dBc in a 15 kHz band centered about the carrier exclu sive of discrete spurious signals 1 Connect the equipment as shown in the diagram below The 1 MHz filter removes the sum frequency mixer output and the 15 kHz filter sets the noise bandwidth of the measurement AC DC Voltmeter 1 MHz Lowpass 15 kHz Lowpass Filter Filter 11 0 KQ 1 0 0015 uF 5 Figure 6 1 Phase Noise Measurement 2 Set the DS345 to sine wave 10 001 MHz 13 dBm The frequency stan dard should be 10 MHz gt 10 dBm 3 Record the AC voltage reading 4 Set the DS345 to 10 0 MHz Measure the DC signal from the mixer Use the DS345 s PHASE control to minimize the DC voltage value 5 Set the voltmeter to AC and measure the mixer output Calculate the ratio of this voltage to that obtained in step 3 dB 20 log Vs V3 Add 6 dB to this value to compensate for the mixer This value should be less than 55 dB Record the result HMI Performance Tests SQUARE WAVE RISE TIME This test measures the rise time and aberrations of the
4. DS345 Description Modulation RAM 40MHz Clock Waveform Cauer Filter DDS345 ASIC RAM O 10 MHz 10 MHz Bessel Fiter Filter Square Wave Comparator Function AM Input Output gt Amplitude DAC Amplitude Outpu Attenuators Control Amp alr Figure 2 DS345 Block Diagram A block diagram of the DS345 is shown in Figure 2 The heart of the DS345 is a 40 MHz crystal clock This clock is internally provided but may be phase locked to an external reference The 40 MHz clock controls the DDS345 ASIC waveform RAM and high speed 12bit DAC Sampling theory limits the frequency of the waveform output from the DAC to about 40 of 40 MHz or 15 MHz The 48 bit length of the DDS345 s PIR s sets the frequency reso lution to about 146 nHz These parameters and the DAC s 12 bit resolution define the performance limits of the DS345 2 2 es troduction im The reconstruction filter is key to accurately reproducing a waveform in a sampled data system The DS345 contains two separate filters For sine wave generation the output of the DAC goes through a 9th order Cauer filter while ramps triangles and arbitrary waveforms pass instead through a 10 MHz 7h order Bessel filter The Cauer filter has a cutoff frequency of 16 5 MHz and a stopband attenuation of 85dB and also includes a peaking circuit to correct for the sine x x amplitude response characteristic of a sampled system This filter eliminates any alias frequencies from the waveform
5. 10 SL Capacitor Ceramic Disc 50V 10 SL Capacitor Ceramic Disc 50V 10 SL Cap Monolythic Ceramic 50V 20 Z5U Cap Monolythic Ceramic 50V 20 Z5U Capacitor Ceramic Disc 50V 10 SL Capacitor Ceramic Disc 50V 10 SL Capacitor Ceramic Disc 50V 10 SL Capacitor Ceramic Disc 50V 10 SL Capacitor Ceramic Disc 50V 10 SL Capacitor Ceramic Disc 50V 10 SL Capacitor Ceramic Disc 50V 10 SL Capacitor Ceramic Disc 50V 10 SL Capacitor Ceramic Disc 50V 10 SL Capacitor Ceramic Disc 50V 10 SL Capacitor Ceramic Disc 50V 10 SL 9 13 EE Component Part List C 635 5 00017 501 47P Capacitor Ceramic Disc 50V 10 SL C 640 5 00019 501 68P Capacitor Ceramic Disc 50V 10 SL C 641 5 00019 501 68P Capacitor Ceramic Disc 50V 10 SL C642 5 00256 530 2 8 12 5P Capacitor Variable Misc C 643 5 00106 530 9 0 50P Capacitor Variable Misc C 644 5 00106 530 9 0 50P Capacitor Variable Misc C 645 5 00257 530 20 90P Capacitor Variable Misc C 646 5 00002 501 100P Capacitor Ceramic Disc 50V 10 SL C 647 5 00002 501 100P Capacitor Ceramic Disc 50V 10 SL C 648 5 00007 501 220P Capacitor Ceramic Disc 50V 10 SL C 649 5 00007 501 220P Capacitor Ceramic Disc 50V 10 SL C 650 5 00016 501 470P Capacitor Ceramic Disc 50V 10 SL C 651 5 00016 501 470P Capacitor Ceramic Disc 50V 10 SL C652 5 00023 529 1U Cap Monolythic Ceramic 50V 20 Z5U C 653 5 00015 501 39P Capa
6. 220P 180P 180P 180P 180P 56P 56P 68P 68P 1U 1U 82P 82P 47P 22P 47P 22P 12P 12P 100P 100P 47P Capacitor Ceramic 50V 80 20 Z5U AX Capacitor Ceramic 50V 80 20 Z5U AX Capacitor Ceramic 50V 80 20 Z5U AX Capacitor Ceramic 50V 80 20 Z5U AX Capacitor Ceramic 50V 80 20 Z5U AX Capacitor Tantalum 35V 20 Rad Capacitor Ceramic 50V 80 20 Z5U AX Capacitor Ceramic 50V 80 20 Z5U AX Capacitor Ceramic 50V 80 20 Z5U AX Capacitor Ceramic 50V 80 20 Z5U AX Capacitor Ceramic 50V 80 20 Z5U AX Capacitor Ceramic 50V 80 20 Z5U AX Capacitor Tantalum 35V 20 Rad Capacitor Tantalum 35V 20 Rad Capacitor Tantalum 35V 20 Rad Capacitor Tantalum 35V 20 Rad Capacitor Tantalum 35V 20 Rad Capacitor Ceramic Disc 50V 10 SL Capacitor Ceramic Disc 50V 10 SL Capacitor Ceramic Disc 50V 10 SL Capacitor Ceramic Disc 50V 10 SL Capacitor Ceramic Disc 50V 10 SL Capacitor Ceramic Disc 50V 10 SL Capacitor Ceramic Disc 50V 10 SL Capacitor Ceramic Disc 50V 10 SL Capacitor Ceramic Disc 50V 10 SL Capacitor Ceramic Disc 50V 10 SL Capacitor Ceramic Disc 50V 10 SL Capacitor Ceramic Disc 50V 10 SL Capacitor Ceramic Disc 50V 10 SL Capacitor Ceramic Disc 50V 10 SL Capacitor Ceramic Disc 50V 10 SL Capacitor Ceramic Disc 50V 10 SL Capacitor Ceramic Disc 50V 10 SL Capacitor Ceramic Disc 50V
7. Diode Integrated Circuit Thru hole Pkg Integrated Circuit Thru hole Pkg Integrated Circuit Thru hole Pkg Integrated Circuit Thru hole Pkg Integrated Circuit Thru hole Pkg Integrated Circuit Thru hole Pkg Integrated Circuit Thru hole Pkg STATIC RAM I C Integrated Circuit Thru hole Pkg Integrated Circuit Thru hole Pkg Integrated Circuit Thru hole Pkg STATIC RAM I C STATIC RAM I C STATIC RAM I C Integrated Circuit Integrated Circuit Integrated Circuit Integrated Circuit Integrated Circuit Integrated Circuit Integrated Circuit Integrated Circuit Integrated Circuit Integrated Circuit Integrated Circuit Integrated Circuit Integrated Circuit Integrated Circuit Integrated Circuit Integrated Circuit Integrated Circuit Integrated Circuit Integrated Circuit Integrated Circuit Relay Relay Integrated Circuit Thru hole Pkg Relay Integrated Circuit Thru hole Pkg Integrated Circuit Thru hole Pkg Integrated Circuit Thru hole Pkg Crystal Spacer Hardware Misc Connector Misc Iron Powder Core Thru hole Pkg Thru hole Pkg Thru hole Pkg Thru hole Pkg Thru hole Pkg Thru hole Pkg Thru hole Pkg Thru hole Pkg Thru hole Pkg Thru hole Pkg Thru hole Pkg Thru hole Pkg Thru hole Pkg Thru hole Pkg Thru hole Pkg Thru hole Pkg Thru hole Pkg Thru hole Pkg Thru hole Pkg Thru hole Pkg ee ee ee E E a a a ee 9 20 ees Component Part List i Zo 6 0009
8. If the center frequency or span is changed such that the sweep frequencies are out of the allowed range an er ror will be displayed on the front panel SWEEP MARKERS The DS345 has two sweep markers that may be used to indicate any two fre quencies in the sweep The MARKER output is a TTL compatible signal that goes high when the sweep frequency crosses the start marker frequency and low when the sweep frequency crosses the stop marker frequency In a trian gle sweep the markers are only active on the up sweep The marker positions may be set by entering the marker start and stop frequencies or the center frequency and span Marker Start and Stop The marker start and stop frequencies are independent of each other and are set by pressing SHIFT MRK START and SHIFT MRK STOP respectively The frequencies can be set to any value from 1 WHz to 30 2 MHz If the mark er start frequency is lower than the marker stop frequency the MARKER out put will initially be low go high when the sweep crosses the start marker posi tion and go low again when the sweep crosses the stop marker position If the marker start frequency is greater than the marker stop frequency the MARKER output will be initially high go low when the sweep crosses the stop marker position and go high again when the sweep crosses the start marker position If either of the marker positions are outside of the sweep range the marker output will behave as if the sweep had crossed its
9. Pressing SHIFT RS232 again displays the RS232 baud rate selection Baud rates of 300 600 1200 2400 4800 9600 or 19200 are set with the MODIFY keys NOTE If no interface option is present the message no interface will be dis played when the RS232 menu is accessed The GPIB and RS232 interfaces are exclusive only one may be active at a given time the GPIB interface is automatically disabled when RS232 is enabled User Service Requests While GPIB is enabled the user may issue a service request SRQ by press ing SHIFT SRQ followed by any of the UNITS keys The message srq sent will be displayed and the SRQ LED will light The SRQ LED will go off after the host computer does a serial poll of the DS345 The user service re quest is in addition to the usual service requests based on status conditions see PROGRAMMING section for details Communications Data Press SHIFT DATA to display the last 256 characters of data that the DS345 has received This display is a scrollable 4 character window into the DS345 s input data queue The data is displayed in ASCII hex format with each input character represented by 2 hexadecimal digits The most recently received character has a decimal point indicator Pressing MODIFY DOWN ARROW scrolls the display earlier in the queue and MODIFY UP ARROW scrolls later in the queue The display cannot be moved later than the last character received 2 26 S245 Setup AUTO TEST AND CALIBR
10. R716 R717 R718 R719 R 720 R 721 R 722 R 723 R 724 R 725 R 726 R 727 R 728 R 729 R 730 R 731 R 732 R 734 R 735 R 736 R 737 R 738 R 739 S0300 T 201 T 202 T 600 T 601 T 602 T 603 T 604 T 605 T 606 T 607 T 608 U1 U2 U 100 U 102 U 103 U 104 U 105 U 106 U 107 U 108 U 109 4 00097 401 4 00097 401 4 00030 401 4 00130 407 4 00130 407 4 00138 407 4 00188 407 4 00739 407 4 00030 401 4 00132 407 4 00132 407 4 00065 401 4 00031 401 4 00031 401 4 00031 401 4 00031 401 4 00075 401 4 00031 401 4 00031 401 4 00030 401 4 00030 401 4 00356 407 4 00130 407 4 00130 407 4 00356 407 4 00021 401 4 00193 407 1 00108 150 6 00009 610 6 00101 601 6 00100 601 6 00101 601 6 00101 601 6 00102 601 6 00103 601 6 00103 601 6 00103 601 6 00101 601 6 00104 601 3 00853 360 3 00852 360 3 00270 340 3 00094 340 3 00270 340 3 00037 340 3 0041 1 340 3 0041 1 340 3 00087 340 3 00088 340 3 00430 340 68 68 10 1 00K 1 00K 10 0K 4 99K 113 10 1 10K 1 10K 3 3K 100 100 100 100 39 100 100 10 10 20 1 00K 1 00K 20 1 0K 499 PLCC 68 TH T1 1 X65 T37 10 10T T37 10 5T T37 10 10T T37 10 10T T37 6 13T T37 10 9T T37 10 9T T37 10 9T T37 10 10T T37 10 7T MC10ELT25 SPT5300 74HC4051 LM311 74HC4051 74HC138 74HC273 74HC273 LF347 LF353 AD7547JN Resistor Carbon Film 1 4W 5 Resistor Carbon Film 1 4W 5 Resistor Carbon Film 1 4W 5 Resistor Metal Film 1 8W
11. SHIFT MRK SPAN sets the positions of the markers to the ex tremes of the sweep span The marker start frequency will be set to the sweep start frequency and the marker stop frequency will be set to the sweep stop frequency This function is useful for finding the markers when setting up a sweep Span to Marker Press SHIFT SPAN MRK to set the sweep span to the marker positions Now the sweep start frequency will be set to the marker start frequency and the sweep stop frequency will be set to the marker stop frequency This func tion can be used to zoom in on a marked section of the sweep If this func tion sets the sweep frequencies to a value not allowed for the selected wave form an error will be generated and the sweep disabled SWEEP OUTPUT The rear panel SWEEP output is a 0 10 V analog output that ramps linearly during a sweep The output voltage is OV at the sweep start frequency and 10V at the sweep stop frequency during TRIANGLE sweeps the SWEEP output will go from OV to 10V to OV This output may be used to drive a chart recorder or x y oscilloscope BLANK LIFT OUTPUT This is a TTL compatible output that is low during the upsweep of a sweep and high during the during the downsweep or sweep reset This output may be used to blank the retrace of an x y oscilloscope or lift the pen on a chart recorder Figure 2 Auxilliary output waveforms Sweep Output eee ge during different types of sweeps ov Blank Lift Output RAM
12. Zo Zo 3 00165 340 3 00045 340 3 00049 340 3 00446 340 3 00446 340 3 00446 340 3 00446 340 3 00446 340 0 00079 031 0 00500 000 7 00720 709 74HC08 74HC32 74HC74 6N137 6N137 6N137 6N137 6N137 4 40X3 16 M F 554808 1 DS345 18 Integrated Circuit Integrated Circuit Integrated Circuit Integrated Circuit Integrated Circuit Integrated Circuit Integrated Circuit Integrated Circuit Standoff Hardware Misc Lexan Overlay Thru hole Pkg Thru hole Pkg Thru hole Pkg Thru hole Pkg Thru hole Pkg Thru hole Pkg Thru hole Pkg Thru hole Pkg ORO ee Miscellaneous and Chassis Assembly Parts List Ref No SRS Part No U 202 3 00345 342 ZO 0 00150 026 Zo 0 00179 000 Zo 0 00180 000 Zo 0 00187 021 Zo 0 00204 000 ZO 0 00248 026 Zo 0 00271 000 Zo 0 00315 021 Zo 0 00326 026 Zo 0 00590 066 Zo 7 00122 720 Zo 7 00217 735 Zo 7 00259 720 Zo 7 00260 720 Value 27C512 120 4 40X1 4PF RIGHT FOOT LEFT FOOT 4 40X1 4PP REAR FOOT 10 32X3 8TRUSSP BUMPER 6 32X7 16 PP 8 32X1 4PP CU TAPE SWTH DG535 36 PS300 40 SR560 28 SR560 27 Description EPROM PROM I C Screw Black All Types Hardware Misc Hardware Misc Screw Panhead Phillips Hardware Misc Screw Black All Types Hardware Misc Screw Panhead Phillips Screw Black All Types Copper Foil Tape Self Adhesive Fabricated Part Injection Molded Plastic Fabricated Part Fabricated Part 9 22
13. and trigger errors red can make the TRIG D LED appear orange Once a burst is triggered the DS345 will ignore all other triggers until the burst is complete EE Modulation and Sweeps I FREQUENCY SWEEPS Introduction The DS345 can frequency sweep its function output for sine square triangle and ramp waves The sweeps may be up or down in frequency and may be linear or log in nature The frequency changes during the sweep are phase continuous and the sweep time may be set between 0 001 and 1000 sec onds The DS345 has an analog SWEEP output that may be used to drive an x y recorder or oscilloscope a TTL BLANK LIFT output that can lift a chart recorder pen during the sweep retrace and a TTL MARKER output that may be set to make transitions at two programmable frequencies during the sweep Sweep Type Pressing the MODULATION TYPE UP DOWN ARROW keys sets the sweep to either a linear or log sweep The output frequency in a linear sweep chang es linearly during the sweep time The output frequency in a log sweep changes exponentially during the sweep time spending an equal amount of time in each decade of frequency For example in a sweep from 1 kHz to 100 kHz the sweep will spend half the time in the 1 kHz to 10 kHz range and half the time in the 10 kHz to 100 kHz range It should be noted that these are digital sweeps and that the sweep is actually composed of 1500 to 3000 discrete frequency points depending on the sweep rate Sweep
14. or vector i 1 format In point mode j is the number of points in the waveform 16300 maximum while in vector format j is the number of vertic es 6144 maximum The data is sent as 16 bit binary data words The data must be followed by a 16 bit checksum to ensure data integrity The check sum is the 16bit sum of the data words that have been sent If the checksum sent does not match the one calculated by the DS345 an error will be gener ated If the data sent is valid and the DS345 s function is set to ARB the waveform will automatically be output Otherwise the function must be set to ARB to output the downloaded waveform To load a waveform follow these steps 1 Send the query LDWF i j where i and j are appropriate for the waveform type and number of points desired 2 Wait until the DS345 returns 1 indicating that it is ready to receive data 3 Send the waveform data discussed below There should be j data points sent 4 Send the 16 bit checksum the sum of j data points The waveform data is send as 16 bit binary data In point mode each data point consists of a 16 bit amplitude word Each value should be in the range 2047to 2047 In vector mode each data point consists of a 16 bit x vertex word and a 16 bit y vertex word for a total of 2 j 16 bit words Each x value must be in the range 0 to 16299 and must be greater than or equal to the val ue of the previous x value Each y value must be in the range 2047 to 204
15. sets the start frequency to the start marker frequency and the stop frequency to the stop marker frequency STFR x The STFR command sets the sweep start frequency to x Hertz An error will be generated if the sweep frequency is less than or equal to zero or greater than allowed by the current function The STFR query returns the current sweep start frequency If the start frequency is greater than the stop frequen cy the SPFR command a downward sweep from maximum to minimum fre quency will be generated TRAT x The TRAT command sets the trigger rate for internally triggered single sweeps and bursts to x Hertz x is rounded to two significant digits and may range from 0 001 Hz to 10 kHz The TRAT query returns the current trigger rate TSRC i The TSRC command sets the trigger source for bursts and sweeps to i The correspondence of i to source is shown in the table below The TSRC query returns the current trigger source Waveform SINGLE INTERNAL RATE SLOPE EXTERNAL SLOPE EXTERNAL LINE AON OW For single sweeps and bursts the TRG command triggers the sweep Arbitrary Waveform and Modulation Commands AMRT i The AMRT command sets the arbitrary modulation rate divider to i i may range from 1 to 223 1 This controls the rate at which arbitrary modulations are generated Arbitrary AM takes 0 3 us per point arb FM takes 2 us per point and arb PM takes 0 5 us per point The AMRT query returns the cur rent di
16. with a high impedance termi nation as Vref 3 Connect the 50Q terminator and measure the DC voltage The new value for calbyte 6 old calbyte 6 Vref 2 Vdc 4 Set the DS345 to 2 5 V offset Measure the DC output value The new val ue for calbyte 7 old calbyte 7 Vref 4 Vdc 5 Set the DS345 to 1 25 V offset Measure the DC output value The new value for calbyte 8 old calbyte 8 Vref 8 Vdc 6 6 es Calibration a 6 Set the DS345 to 625mV offset Measure the DC voltage The new value for calbyte 9 old calbyte 9 Vref 16 Vdc 7 Set the DS345 to 312mV offset Measure the DC voltage The new value for calbyte 10 old calbyte 10 Vref 32 05 Vdc 8 Set the DS345 to 156mV offset Measure the DC voltage The new value for calbyte 11 old calbyte 11 Vref 64 1 Vdc 9 Set the DS345 to 78mV offset Measure the DC voltage The new value for calbyte 12 old calbyte 12 Vref 128 21 Vdc 10 Set the DS345 to 39mV offset Measure the DC voltage The new value for calbyte 13 old calbyte 13 Vref 256 41 Vdc Carrier Null Calibration This calibration nulls the carrier feedthrough of the DS345 s frequency dou bler This calibration depends on frequency and is calibrated at 98 frequency points in the DS345 s frequency range This calibration must be done before the amplitude calibrations 1 Set the DS345 to sine wave 1 kHz 8 Vpp O V offset Connect the DS345 s output to the FFT spect
17. 0 517 Vrms 0 259 Vrms 129 mVrms 77 6 mVrms 41 4 mVrms 25 85 mVrms 5 15 Vrms 5 15 Vrms 5 15 Vrms 2 97 Vrms 2 97 Vrms 2 97 Vrms BI Performance Tests sine 8 001 MHz 3 Vrms sine 10 001 MHz 3Vrms sine 12 001 MHz 3 Vrms sine 14 001 MHz 3 Vrms sine 16 001 MHz 3 Vrms sine 18 001 MHz 3 Vrms Tolerance 6 3 of X sine 20 001 MHz 3 Vrms sine 22 001 MHz 3 Vrms sine 24 001 MHz 3 Vrms sine 26 001 MHz 3 Vrms sine 28 001 MHz 3 Vrms sine 30 001 MHz 3 Vrms square 10 Vpp DC Offset Accuracy DC only 5 0 V 4 925 V 5 075 V 5 0 V 5 075 V 4 925 V 0 0 V 0 0002 V 0 0002 V DC Offset Accuracy DC AC 1 kHz 10 Vpp 0 Vdc 100 kHz 10 Vpp 0 Vdc 1 MHz 10 Vpp 0 Vdc 10 MHz 10 Vpp 0 Vdc 20 MHz 10 Vpp 0 Vdc 30 MHz 10 Vpp 0 Vdc Subharmonics sine 102 kHz 23 98 dBm 26 02 dBm sine 1 002 MHz 23 98 dBm 26 02 dBm sine 10 002 MHz 23 98 dBm 26 02 dBm sine 20 002 MHz 23 98 dBm 26 02 dBm sine 30 002 MHz 23 98 dBm 26 02 dBm Spurious Signals sine 26 662 MHz sine 20 004 MHz sine 18 MHz Harmonic Distortion sine 100 Hz 1 Vpp sine 1 kHz 1 Vpp sine 10 kHz 1 Vpp sine 50 kHz 1 Vpp sine 500 kHz 1 Vpp E Performance Tests Ml sine 5 MHz 1 Vpp sine 15 MHz 1 Vpp sine 30 MHz 1 Vpp Phase Noise sine 10 001 MHz 13 dBm V1 sine 10 0 MHz 13 dBm V2 noise 20 log V2 V1 6 dB Square Wave Rise Time square 1 MHz 10 Vpp 10 to 90 rise time square 1 MHz 1
18. 00120 329 7915 Voltage Reg TO 220 TAB Package U 102 3 00149 329 LM317T Voltage Reg TO 220 TAB Package U 103 3 00149 329 LM317T Voltage Reg TO 220 TAB Package U 104 3 00141 329 LM337T Voltage Reg TO 220 TAB Package U 105 3 00149 329 LM317T Voltage Reg TO 220 TAB Package U 106 3 00141 329 LM337T Voltage Reg TO 220 TAB Package U 107 3 00112 329 7805 Voltage Reg TO 220 TAB Package U 108 3 00319 340 AD586JN Integrated Circuit Thru hole Pkg U 109 3 00088 340 LF353 Integrated Circuit Thru hole Pkg U 110 3 00039 340 74HC14 Integrated Circuit Thru hole Pkg U 111 3 00088 340 LF353 Integrated Circuit Thru hole Pkg U 200 3 00216 340 Z8800 Integrated Circuit Thru hole Pkg U 201 3 00261 340 74LS245 Integrated Circuit Thru hole Pkg U 203 3 00259 340 74HCT373 Integrated Circuit Thru hole Pkg U204 3 00299 341 32KX8 70L STATIC RAM I C U 205 3 00158 340 74HC154N Integrated Circuit Thru hole Pkg U 207 3 00155 340 74HC04 Integrated Circuit Thru hole Pkg U 208 3 00396 340 74HCT04 Integrated Circuit Thru hole Pkg U 209 3 00400 340 74HCT32 Integrated Circuit Thru hole Pkg U210 3 00199 340 74HC4538 Integrated Circuit Thru hole Pkg U 211 3 00049 340 74HC74 Integrated Circuit Thru hole Pkg U214 3 00400 340 74HCT32 Integrated Circuit Thru hole Pkg U 300 3 00064 340 CA3081 Integrated Circuit Thru hole Pkg U 301 3 00401 340 74HCT244 Integrated Circuit Thru hole Pkg U302 3 00401 340 74HCT244 Integrated Cir
19. 001Hz to 40 000 000 0Hz Note that the sampling frequency can only be 40MHZ N where N is an integer If a frequency is entered where N is not an integer the DS345 will round it to the closest 40MHZ N value This selection is used to set communication parameters for the interface between AWC and the DS345 When you select this menu item the program checks for available VISA resources on your system Depending on your system this may take several seconds 7 5 ES Arbitrary Waveform Composer iis Enable Local Trigger Menu Zoom Menu Zoom Zoom In Zoom Out Pan Right Pan Left Full View Help Menu AWC Help SRS AWC Info Notes RS232 For serial communication click the RS232 box Select the Baud rate and the serial port COM1 COM2 etc from their respective menu rings The baud rate must correspond to that of the DS345 Be sure that the DS345 s RS232 interface is enabled GPIB If the GPIB button is pressed the available GPIB addresses found on the system are displayed in the menu ring Select the GPIB address that corresponds to the GPIB address set on the DS345 This selection takes the DS345 out of remote mode and enables local front panel control The Trigger menu allows setting the DS345 s trigger generator parameters for triggered bursts of arbitrary waveforms When one of the trigger choices is selected the DS345 will automatically be set to BURST modulation the burst count to one and the modulation en
20. 10 NPO Capacitor Ceramic Disc 50V 20 Z5U Capacitor Ceramic Disc 50V 10 NPO Capacitor Ceramic Disc 50V 20 Z5U Capacitor Ceramic Disc 50V 20 Z5U Capacitor Ceramic Disc 50V 10 SL Capacitor Ceramic Disc 50V 10 NPO Cap Monolythic Ceramic 50V 20 Z5U Capacitor Tantalum 35V 20 Rad Capacitor Ceramic Disc 50V 10 SL Capacitor Ceramic Disc 50V 10 SL Capacitor Ceramic Disc 50V 10 SL Capacitor Ceramic Disc 50V 10 SL Cap Monolythic Ceramic 50V 20 Z5U Cap Monolythic Ceramic 50V 20 Z5U Cap Monolythic Ceramic 50V 20 Z5U Capacitor Ceramic Disc 50V 20 Z5U Cap Monolythic Ceramic 50V 20 Z5U Capacitor Mylar Poly 50V 5 Rad Capacitor Ceramic Disc 50V 10 SL Capacitor Ceramic Disc 50V 10 SL Capacitor Mylar Poly 50V 5 Rad Capacitor Mylar Poly 50V 5 Rad Capacitor Mylar Poly 50V 5 Rad Capacitor Mylar Poly 50V 5 Rad Capacitor Mylar Poly 50V 10 Rad Capacitor Ceramic Disc 50V 10 SL Capacitor Ceramic Disc 50V 10 SL Capacitor Ceramic Disc 50V 10 SL Capacitor Ceramic Disc 50V 10 SL 9 11 EE Component Part List C 413 C 414 C 415 C 416 C 417 C 508 C 509 C 510 C512 C 513 C514 C515 C 516 C 517 C 518 C 519 C 520 C 521 C 522 C 523 C 524 C 525 C 526 C 527 C 528 C 529 C 530 C 531 C 532 C 533 C 534 C 535 C 536 C 537 C 538 C 539 C 540 C 541 C 542 C 555 C 556 C 557 C 558 C 559 C 564 C 565 C 566
21. 15 EE Component Part List R18 4 01463 461 220 Thick Film 5 200 ppm Chip Resistor R 20 4 01439 461 22 Thick Film 5 200 ppm Chip Resistor R21 4 01439 461 22 Thick Film 5 200 ppm Chip Resistor R 22 4 01439 461 22 Thick Film 5 200 ppm Chip Resistor R 100 4 00031 401 100 Resistor Carbon Film 1 4W 5 R 101 4 00031 401 100 Resistor Carbon Film 1 4W 5 R 102 4 00031 401 100 Resistor Carbon Film 1 4W 5 R 103 4 00031 401 100 Resistor Carbon Film 1 4W 5 R 105 4 00048 401 2 2K Resistor Carbon Film 1 4W 5 R 106 4 00021 401 1 0K Resistor Carbon Film 1 4W 5 R 107 4 00034 401 10K Resistor Carbon Film 1 4W 5 R 108 4 00034 401 10K Resistor Carbon Film 1 4W 5 R 109 4 00034 401 10K Resistor Carbon Film 1 4W 5 R110 4 00034 401 10K Resistor Carbon Film 1 4W 5 R111 4 00034 401 10K Resistor Carbon Film 1 4W 5 R112 4 00471 401 82 Resistor Carbon Film 1 4W 5 R113 4 00471 401 82 Resistor Carbon Film 1 4W 5 R114 4 00471 401 82 Resistor Carbon Film 1 4W 5 R115 4 00471 401 82 Resistor Carbon Film 1 4W 5 R116 4 00048 401 2 2K Resistor Carbon Film 1 4W 5 R117 4 00218 408 10 00K Resistor Metal Film 1 8W 0 1 25ppm R118 4 00218 408 10 00K Resistor Metal Film 1 8W 0 1 25ppm R119 4 00021 401 1 0K Resistor Carbon Film 1 4W 5 R 120 4 00021 401 1 0K Resistor Carbon Film 1 4W 5 R 121 4 00471 401 82 Resistor Carbon Film 1 4W 5 R 122 4 00471 401 82 Resistor Carbon Fi
22. 20 Rad Capacitor Tantalum 35V 20 Rad Capacitor Tantalum 35V 20 Rad Capacitor Ceramic 50V 80 20 Z5U AX Capacitor Ceramic 50V 80 20 Z5U AX Capacitor Ceramic 50V 80 20 Z5U AX Capacitor Ceramic 50V 80 20 Z5U AX Capacitor Ceramic 50V 80 20 Z5U AX Capacitor Ceramic 50V 80 20 Z5U AX Capacitor Ceramic 50V 80 20 Z5U AX Capacitor Ceramic 50V 80 20 Z5U AX Capacitor Ceramic 50V 80 20 Z5U AX Capacitor Ceramic 50V 80 20 Z5U AX Capacitor Ceramic 50V 80 20 Z5U AX Capacitor Ceramic 50V 80 20 Z5U AX Capacitor Ceramic 50V 80 20 Z5U AX Capacitor Ceramic 50V 80 20 Z5U AX Capacitor Ceramic 50V 80 20 Z5U AX Capacitor Ceramic 50V 80 20 Z5U AX Capacitor Ceramic 50V 80 20 Z5U AX Capacitor Ceramic 50V 80 20 Z5U AX Capacitor Ceramic 50V 80 20 Z5U AX Capacitor Ceramic 50V 80 20 Z5U AX Capacitor Ceramic 50V 80 20 Z5U AX Capacitor Ceramic 50V 80 20 Z5U AX Capacitor Ceramic 50V 80 20 Z5U AX Capacitor Ceramic 50V 80 20 Z5U AX Capacitor Ceramic 50V 80 20 Z5U AX Capacitor Ceramic 50V 80 20 Z5U AX Capacitor Ceramic 50V 80 20 Z5U AX Capacitor Ceramic 50V 80 20 Z5U AX Capacitor Ceramic 50V 80 20 Z5U AX Capacitor Tantalum 35V 20 Rad Capacitor Ceramic 50V 80 20 Z5U AX Capacitor Ceramic 50V 80 20 Z5U AX Capacitor Ceramic 50V 80 20 Z5U AX Capacitor Ceramic 50V 80 20 Z5U AX Capacitor Ceramic 50V 80
23. 20 Z5U AX Capacitor Ceramic 50V 80 20 Z5U AX Capacitor Ceramic 50V 80 20 Z5U AX Capacitor Ceramic 50V 80 20 Z5U AX Capacitor Tantalum 35V 20 Rad Capacitor Tantalum 35V 20 Rad 9 12 ees Component Part List i C 574 C 575 C 576 C 580 C 581 C 586 C 587 C 588 C 589 C 590 C 591 C 592 C 593 C 595 C 596 C 597 C 598 C 600 C 601 C 604 C 605 C 606 C 607 C 608 C 609 C 610 C 611 C 612 C 613 C 614 C 615 C 616 C 617 C 618 C 619 C 620 C 621 C 622 C 623 C 624 C 625 C 626 C 627 C 628 C 629 C 630 C 631 C 632 C 633 C 634 5 00262 548 5 00262 548 5 00262 548 5 00262 548 5 00262 548 5 00100 517 5 00262 548 5 00262 548 5 00262 548 5 00262 548 5 00262 548 5 00262 548 5 00100 517 5 00100 517 5 00100 517 5 00100 517 5 00100 517 5 00249 501 5 00249 501 5 00002 501 5 00002 501 5 00002 501 5 00002 501 5 00002 501 5 00002 501 5 00002 501 5 00002 501 5 00007 501 5 00007 501 5 00249 501 5 00249 501 5 00249 501 5 00249 501 5 00132 501 5 00132 501 5 00019 501 5 00019 501 5 00023 529 5 00023 529 5 00021 501 5 00021 501 5 00017 501 5 00008 501 5 00017 501 5 00008 501 5 00004 501 5 00004 501 5 00002 501 5 00002 501 5 00017 501 01U AXIAL 01U AXIAL 01U AXIAL 01U AXIAL 01U AXIAL 2 2U 01U AXIAL 01U AXIAL 01U AXIAL 01U AXIAL 01U AXIAL 01U AXIAL 2 2U 2 2U 2 2U 2 2U 2 2U 180P 180P 100P 100P 100P 100P 100P 100P 100P 100P 220P
24. 208 U 209 U 300 U 301 U 302 U 303 U 304 U 305 U 306 U 307 U 312 U 313 U 314 U 401 U 403 U 404 U 405 U 406 U 409 U 410 U 411 U 412 U 413 U 414 U 415 U 416 U 417 U 505 U 506 U 600 U 602 U 603 U 604 U 700 U 702 U 703 U 704 X 200 Zo Zo Zo Zo 3 00088 340 3 00088 340 3 00294 340 3 00442 301 3 00333 340 3 00105 340 3 00385 340 3 00144 340 3 00432 340 3 00151 340 3 00421 340 3 01116 341 3 00261 340 3 00387 340 3 00387 340 3 00433 341 3 00433 341 3 00433 341 3 00165 340 3 00396 340 3 00045 340 3 00058 340 3 00411 340 3 00411 340 3 00238 340 3 00087 340 3 00385 340 3 00091 340 3 00088 340 3 00430 340 3 00088 340 3 00411 340 3 00049 340 3 00411 340 3 00088 340 3 00356 340 3 00356 340 3 00436 340 3 00196 335 3 00196 335 3 00332 340 3 00196 335 3 00436 340 3 00096 340 3 00437 340 6 00454 620 0 00514 030 0 00772 000 1 00389 100 6 00097 614 LF353 LF353 AD96685 MV104 74HC161 LM741 74HC4053 74HC366 74F244 MC10125 F107563FN 71256SA20TP 74LS245 74HC245 74HC245 16KX4 20 16KX4 20 16KX4 20 74HCO8 74HCT04 74HC32 AD7524 74HC273 74HC273 T4F74 LF347 74HC4053 LF412 LF353 AD7547JN LF353 74HC273 74HC74 74HC273 LF353 74F374 74F374 AD834JN HS 212S 5 HS 2128 5 MPQ3906 HS 2128 5 AD834JN LM317L AD9696KN 40 000MHZ TUBULAR NYLON 1 5 WIRE 4 PIN STRIP T37 10 Integrated Circuit Thru hole Pkg Integrated Circuit Thru hole Pkg Integrated Circuit Thru hole Pkg
25. 232 4 00072 401 330 Resistor Carbon Film 1 4W 5 R 233 4 00021 401 1 0K Resistor Carbon Film 1 4W 5 R 235 4 00021 401 1 0K Resistor Carbon Film 1 4W 5 R 236 4 00031 401 100 Resistor Carbon Film 1 4W 5 R 237 4 00031 401 100 Resistor Carbon Film 1 4W 5 R 238 4 00090 401 560 Resistor Carbon Film 1 4W 5 R 239 4 00103 401 820 Resistor Carbon Film 1 4W 5 R 240 4 00068 401 300 Resistor Carbon Film 1 4W 5 R 241 4 00079 401 4 7K Resistor Carbon Film 1 4W 5 R 242 4 00130 407 1 00K Resistor Metal Film 1 8W 1 50PPM R 243 4 00725 407 191 Resistor Metal Film 1 8W 1 50PPM R 244 4 00079 401 4 7K Resistor Carbon Film 1 4W 5 R 245 4 00034 401 10K Resistor Carbon Film 1 4W 5 R 246 4 00079 401 4 7K Resistor Carbon Film 1 4W 5 R 247 4 00079 401 4 7K Resistor Carbon Film 1 4W 5 R 248 4 00032 401 100K Resistor Carbon Film 1 4W 5 R 249 4 00089 401 56 Resistor Carbon Film 1 4W 5 R 250 4 00031 401 100 Resistor Carbon Film 1 4W 5 R 251 4 00031 401 100 Resistor Carbon Film 1 4W 5 R 252 4 00043 401 180 Resistor Carbon Film 1 4W 5 R 253 4 00088 401 51K Resistor Carbon Film 1 4W 5 R 255 4 00029 401 1 8K Resistor Carbon Film 1 4W 5 R 301 4 00034 401 10K Resistor Carbon Film 1 4W 5 R 302 4 00034 401 10K Resistor Carbon Film 1 4W 5 R 303 4 00034 401 10K Resistor Carbon Film 1 4W 5 R 304 4 00034 401 10K Resistor Carbon Film 1 4W 5 R 400 4 00433 407 931 Resi
26. COATED GREEN COATED RED COATED 1N4148 1N4148 1N4148 1N4148 1N4148 1N4148 1N5822 1N5822 1N5822 1N5822 LED Rectangular LED Rectangular LED Rectangular Bicolor LED Coated Rectangular LED Rectangular LED Rectangular LED Rectangular LED Rectangular LED Rectangular LED Rectangular LED Coated Rectangular LED Rectangular LED Rectangular LED Rectangular LED Rectangular LED Rectangular LED Rectangular LED Rectangular LED Coated Rectangular LED Coated Rectangular LED Coated Rectangular LED Coated Rectangular LED Coated Rectangular LED Coated Rectangular LED Rectangular LED Coated Rectangular LED Coated Rectangular LED Coated Rectangular LED Coated Rectangular LED Coated Rectangular LED Coated Rectangular LED Coated Rectangular LED Coated Rectangular LED Coated Rectangular LED Coated Rectangular LED Coated Rectangular LED Coated Rectangular LED Coated Rectangular LED Coated Rectangular LED Coated Rectangular Diode Diode Diode Diode Diode Diode Diode Diode Diode Diode 9 3 EE Component Part List D105 3 00062 340 KBP201G BR 81D Integrated Circuit Thru hole Pkg D106 3 00011 303 RED LED T1 Package D108 3 00062 340 KBP201G BR 81D Integrated Circuit Thru hole Pkg D109 3 00226 301 1N5822 Diode D110 3 00004 301 1N4148 Diode D111 3 00004 301 1N4148 Diode D112 3 00004 301 1N4148 Diode D200 3 00004 301 1N4148 Diode D201 3 000
27. Depth 0 to 100 AM or DSBSC Rate 0 001 Hz to 10 kHz internal 20 KHz max external Distortion lt 35dB at 1kHz 80 depth vi N Specifications Ma DSB Carrier Ext Input FREQUENCY MODULATION Source Rate Span PHASE MODULATION Source Rate Span FREQUENCY SWEEP Type Waveform Time Span Markers Sweep Output BURST MODULATION Waveform Frequency Count TRIGGER GENERATOR Source Rate External Output TIMEBASE Accuracy Aging Input Output Optional Timebase Type Stability Aging Short Term lt 35db typical at 1 kHz modulation rate DSBSC 5V for 100 modulation 100 kW impedance Internal sine square triangle ramp 0 001 Hz to 10 kHz 1 uHz to 30 2 MHz 100 kHz for triangle or ramp Internal sine square triangle ramp 0 001 Hz to 10 kHz 7199 999 Linear or Log phase continuous up down up down single sweep 0 001s to 1000s 1 wHz to 30 2 MHz 100 kHz for triangle ramp Two markers may be set at any sweep point TTL output 0 10 V linear ramp signal syncronized to sweep any waveform except NOISE may be BURST Sine square to 1 MHz triangle ramp to 100 kHz arbitrary to 40 MHz sample rate 1 to 30 000 cycles burst 11s to 500s burst time limits Single Internal External Line 0 001 Hz to 10 kHz internal 2 digit resolution Positive or Negative edge TTL input TTL output 5 ppm 20 to 30 C 5 ppm year 10 MHZ N 2 ppm N 1 t
28. LED will be lit When the offset is changed the output signal will briefly go to zero as the output attenuators are switched If the amplitude is zero the offset may be set with three digits of resolution If the amplitude is not zero the larger of the amplitude and offset determines the resolution of both parameters The offset display is automati cally adjusted such that all of the digits that may be changed are displayed PHASE Press PHASE to display and modify the phase of the FUNCTION output Phase is always measured with respect to the internal timebase not the SYNC output The phase may be changed with the keypad and the DEG unit key or using the MODIFY keys The range of the phase setting is 7199 999 and may be set with 0 001 resolution If the function is set to NOISE ARB or modulation is enabled in SWEEP FM or PM modes the phase cannot be changed and the message no Phase will be displayed In BURST modulation mode the PHASE function will set the waveform phase at the start of the burst This is quite useful for starting the burst at a particu lar point in the waveform Zero Phase The current phase may be assigned the value zero by pressing SHIFT REL 0 Subsequent changes to phase will be relative to this value SWEEPS AND MODULATION Introduction MODULATION ON OFF MODULATION TYPE MODULATION WAVEFORM This section of the manual describes the DS345 s modulation capabilities The DS345 has extremely powerful
29. Meaning 0 No Error 1 DS345 not warmed up At least 2 minutes must elapse between power on and calibration 2 Self Test Fail The DS345 must pass its self tests be fore calibration 3 A D Cal Error The DS345 s A to D converter could not be calibrated 4 DC Offset Fail The DS345 was unable to calibrate its DC offset 5 Amplitude Cal Fail The DS345 was unable to calibrate its amplitude control circuitry 6 Doubler Cal Fail The DS345 was unable to calibrate the doubler offset or the gain of the doubler square wave signal path TST The TST common query runs the DS345 internal self tests After the tests are complete the test status is returned The status may have the following values see the TROUBLESHOOTING section for more details Status value Meaning 0 No Error 1 CPU Error The DS345 has detected a problem in its CPU 2 Code Error The DS345 s ROM firmware has a check sum error 3 Sys RAM Error The system RAM failed its test 4 Cal Data Error The DS345 s calibration data has be come corrupt 5 Function Data Error The waveform RAM failed its test 6 Program Data Error The modulation program RAM failed its test 7 Trigger Error The trigger detection circuits failed their test 8 A D D A Error Either the A D or one of the D A s failed its test The front panel message is more specific 9 Signal Error Either the waveform DAC amplitude con trol or the output amplifier has failed 10 Sync Error The sync
30. Resistor Carbon Film 1 4W 5 Resistor Carbon Film 1 4W 5 Resistor Carbon Film 1 4W 5 Resistor Carbon Film 1 4W 5 Resistor Carbon Film 1 4W 5 Resistor Carbon Film 1 4W 5 Resistor Carbon Film 1 4W 5 Resistor Carbon Film 1 4W 5 Resistor Carbon Film 1 4W 5 Resistor Carbon Film 1 4W 5 Resistor Carbon Film 1 4W 5 Resistor Carbon Film 1 4W 5 Resistor Carbon Film 1 4W 5 Resistor Carbon Film 1 4W 5 Resistor Carbon Film 1 4W 5 Resistor Carbon Film 1 4W 5 Resistor Carbon Film 1 4W 5 Resistor Carbon Film 1 4W 5 Resistor Carbon Film 1 4W 5 Resistor Carbon Film 1 4W 5 Resistor Carbon Film 1 4W 5 Resistor Carbon Film 1 4W 5 Resistor Carbon Film 1 4W 5 Resistor Carbon Film 1 4W 5 Resistor Carbon Film 1 4W 5 Resistor Carbon Film 1 4W 5 Resistor Carbon Film 1 4W 5 Resistor Carbon Film 1 4W 5 Resistor Carbon Film 1 4W 5 Resistor Carbon Film 1 4W 5 Resistor Carbon Film 1 4W 5 Resistor Carbon Film 1 4W 5 Resistor Carbon Film 1 4W 5 Resistor Carbon Film 1 4W 5 Resistor Carbon Film 1 4W 5 Resistor Carbon Film 1 4W 5 Resistor Carbon Film 1 4W 5 Resistor Carbon Film 1 4W 5 Resistor Carbon Film 1 4W 5 Resistor Carbon Film 1 4W 5 Resistor Carbon Comp 1 2W 5 Resistor Carbon Film 1 4W 5 Resistor Carbon Film 1 4W 5 Resistor Carbon Film 1 4W 5 Resistor Carbon Film 1 4W 5 Resistor Carb
31. SIZE We ve changed the step size to 123 Hz and dis played the output frequency again 8 Press MODIFY DOWN ARROW The frequency is decreased by 123 Hz to 9977 Hz 9 Press STEP SIZE then MODIFY UP ARROW The step size is displayed and is increased from 123 Hz to the next larger decade 1 kHz 10 Press STEP SIZE The frequency is displayed again The flashing digit indicates that the step size is 1 kHz 11 Press MODIFY UP ARROW The frequency is incremented to 10 977 kHz Frequency Sweep The next example sets up a linear frequency sweep with markers The DS345 can sweep the output frequency of any function over any range of al lowable output frequencies There are no restrictions on minimum or maxi mum sweep span The sweep time may range from 1 ms to 1000 s The DS345 also has two independent rear panel markers that may be used indi cate specific frequencies in the sweep The MARKER output goes high at the start marker position and low at the stop marker position An oscilloscope that can display three channels is required Attach the FUNCTION output BNC to the oscilloscope terminating the output into 50 ohms Set the scope to 2V div Attach the SWEEP rear panel BNC to the scope and set it to 2V div The scope should be set to trigger on the falling edge of this signal Attach the MARKER rear panel BNC to the scope s third channel This signal will have TTL levels 1 Press SHIFT DEFAULTS This recalls the DS345 s defaul
32. Tantalum 35V 20 Rad Capacitor Tantalum 35V 20 Rad Cap Mini Electrolytic 50V 20 Radial Capacitor Tantalum 35V 20 Rad Capacitor Tantalum 35V 20 Rad Cap Mini Electrolytic 50V 20 Radial Cap Mini Electrolytic 50V 20 Radial Capacitor Tantalum 35V 20 Rad Capacitor Tantalum 35V 20 Rad Capacitor Tantalum 35V 20 Rad Cap Mini Electrolytic 50V 20 Radial Capacitor Tantalum 35V 20 Rad Capacitor Electrolytic 16V 20 Rad Capacitor Ceramic 50V 80 20 Z5U AX Capacitor Ceramic 50V 80 20 Z5U AX Capacitor Ceramic 50V 80 20 Z5U AX Capacitor Ceramic 50V 80 20 Z5U AX Capacitor Ceramic 50V 80 20 Z5U AX Capacitor Ceramic 50V 80 20 Z5U AX Capacitor Ceramic 50V 80 20 Z5U AX Capacitor Ceramic 50V 80 20 Z5U AX Capacitor Ceramic 50V 80 20 Z5U AX Capacitor Ceramic 50V 80 20 Z5U AX Capacitor Ceramic 50V 80 20 Z5U AX Capacitor Ceramic 50V 80 20 Z5U AX Capacitor Ceramic 50V 80 20 Z5U AX Capacitor Ceramic 50V 80 20 Z5U AX Capacitor Ceramic 50V 80 20 Z5U AX Capacitor Ceramic 50V 80 20 Z5U AX Capacitor Ceramic 50V 80 20 Z5U AX Capacitor Ceramic 50V 80 20 Z5U AX Capacitor Ceramic 50V 80 20 Z5U AX 9 1 EE Component Part List C 146 C 147 C 148 C 149 C 150 C 151 C 152 C 153 C 154 C 155 C 156 C 157 C 158 C 159 C 200 C 201 C 204 C 205 C 400 C 401 C 402 C 403 C 600 C 601 C 602 C 603 C 604 C 605 C 6
33. Waveform The DS345 s sweep waveform may be set to single triangle or ramp using the MODULATION WAVEFORM UP DOWN arrow keys With the SINGLE setting the DS345 s output frequency will be the sweep start frequency until a trigger is received The output will then sweep to the stop frequency reset to the start frequency and wait for another trigger see the TRIGGER GENERA TOR section for setting the trigger source If the waveform is set to a RAMP the DS345 will sweep from the start to the stop frequency jump back to the start frequency and repeat continuously If the waveform is a TRIANGLE the DS345 will sweep from the start to the stop frequency sweep back from the stop frequency to the start frequency and repeat continuously Sweep RATE Time The duration of the sweep is set by RATE and the value is entered or modi fied with the keypad The sweep rate may be set over the range of 0 001 Hz to1 kHz The sweep rate is the inverse of the sweep time a 0 001 Hz rate is equal to a 1000s sweep time and a1 kHz rate is equal to a 1 ms sweep time For a TRIANGLE sweep the sweep time is the total time to sweep up and down SWEEP FREQUENCIES The DS345 may sweep over any portion of its frequency range 1 uHz to 30 2 MHz for sine and square waves and 1 wHz to 100 kHz for triangle and ramp waves There are no restrictions on minimum or maximum sweep span The DS345 s sweep range may be set by entering either the start and stop frequencies or the center
34. an error will be generated Once the waveform has been loaded changing the modulation type or waveform will erase that pattern The value i 6 none will be returned for modulation types that don t have an associated waveform such as burst mode The waveform may not be set to i 6 none aOnahWNnN O MENA i The MENA command enables modulation if i 1 and disables modulation if i 0 If any of the modulation parameters are incompatible with the current in strument settings an error will be generated The MENA query returns the current modulation enable status MKSP The MKSP command sets the sweep markers to the extremes of the sweep span That is the marker start frequency is set to the sweep start frequency and the marker stop frequency is set to the sweep stop frequency MRKF i x The MRKF command sets the sweep marker frequency to x If i 0 the marker start frequency will be set if i 1 the stop frequency will be set if i 2 the marker center frequency will be set and if i 3 the marker span will be set The MRKF i query will return marker frequency i MTYP i The MTYP command sets the modulation type to i The correspondence of i to type is shown in the table below The MTYP query returns the current modulation type Waveform LIN SWEEP LOG SWEEP INTERNAL AM FM om BURST ak UN OM PDEV x The PDEV command sets the span of the phase modulation to x degrees x may range from 0 to 7199 999 degrees Note th
35. and flexible built in modulation functions It is capable of AM both simple and double sideband suppressed carrier DSBSC FM PM tone bursts and frequency sweeps The modulation waveform may be a sine square ramp or triangle wave Frequency can be swept up or down at a linear or logarithmic rate A built in trigger generator al lows triggering of single sweeps and bursts For additional flexibility the DS345 can also modulate the output waveform with an arbitrary pattern of amplitude frequency or phase values SWEEP MODULATE SINGLE A al y X START FREQ The SWEEP ON OFF key enables the DS345 s modulation functions Press ing the key toggles the modulation status When modulation is on the MOD SWP LED will light When modulation is enabled the modulation type and modulation parameters are checked for consistency with the selected output function If the selected modulation is illegal for example FM frequen cy out of range for the function the DS345 will display an error message and not enable the modulation The erroneous value must be changed before the modulation is turned on The type of modulation is selected using the MODULATION TYPE UP DOWN arrow keys Most of the output functions can be modulated by any type of modulation However NOISE can only be modulated by the external AM input and ARB waveforms can only be modulated by AM and BURST modulations If an invalid choice is selected the message funct
36. arb modulation command ibwrt ds345 cmd strlen cmd ibrd ds345 cmd 40 read back reply before sending data ibwrt ds345 char data long 4 number 4 number of bytes 4 per data point 4 for checksum sprintf cmd MENA1 n ibwrt ds345 cmd strlen cmd turn modulation on EXAMPLE 3 Arbitrary Phase Modulation This program downloads an arbitrary PM pattern to the DS345 The modulating waveform is a sine wave Since the DS345 expects a list of phase changes we calculate the initial phase of the waveform and then take differences from that phase The program calculates the PM pattern values sets the modulation type to PM modulation waveform to ARB downloads the pattern and enables modulation The program is written in C program to demonstrate arbitrary PM modulation Will generate a sine wave with span of 90deg 45 deg to 45 deg Written in Microsoft C and uses National Instruments GPIB card Assumes DS345 is installed as device name DS345 include lt stdio h gt include lt string h gt include lt stdlib h gt include lt dos h gt include lt math h gt include lt float h gt include lt decl h gt National Instruments header file void main void int ds345 unsigned long data 4000 up to 4000 points 4 bytes each void main char cmd 40 int i number long sum double t s span old new if ds345 ibf
37. cmd FUNC5 n ibwrt ds345 cmd strlen cmd EXAMPLE 5 Vector Mode Arbitrary Waveform This program downloads an arbitrary in vector edit mode The data is number of bytes point 2 for checksum sending data 2 per data arb wf output just a list of x values waveform RAM addresses and amplitude values The program generates a triangle wave whose amplitude linearly grows in time the vertex y values grow and alternate in sign The program is written in C program to donwload vector mode arb wf to DS345 The waveform is a triangle wave linearly increasing i amplitude a christmas tree on its side Written Microsoft C and uses National Instrument GPIB card to be installed as DS345 in IBCONF lt stdio h gt lt string h gt lt stdlib h gt lt dos h gt include include include include n in Expects DS345 include lt decl h gt void main void int ds345 int data 10000 up to 10000 points void main char cmd 40 int i sum number O 3 20 National Instruments header fil x7 ES Program Examples I if ds345 ibfind DS345 lt 0 open National driver printf Cannot find DS345 n exit 1 sum 0 initialize checksum number 250 250 verteces each vertex has an x and y value we will step x in increments of 50 and y in increments of 8 with alternating sign zig zag up and down
38. editing of actual waveform data The editing process is interactive the waveform RAM is updated any time an editing operation takes place Displaying the FUNCTION output on an oscillo scope allows the user to see the waveform change as the data is modified 2 29 BE Arbitrary Waveform Editing Data Display The format of the data display is shown below for both point and vector for mat The data line has two values in both formats The left value is the point vertex number indicating which point vertex is being edited The right hand value is the data for that point Only one value is active flashing at any time The active value is selected by pressing SHIFT RIGHT ARROW or SHIFT LEFT ARROW The active value may be changed with the keypad or MODIFY up down keys In vector format the x y indicator denotes that the data value is either the x value h or y value y for the given vertex The display is switched between x and y by pressing STEP SIZE Point Form 190123 1234 Point point Value Vector Format 0123 h 1234 Vertex a 4 Taata Value x y indicator POINT EDITING The following section describes editing point format arbitrary waveforms Point Number The point number may be set to any value between 0 and the total number of points in the current waveform The point number is set by either the keypad or the MODIFY up down keys The maximum point number is 16 299 there must more than 8 and less than 16 300 points
39. have ex cessive DC offset gt 200mV or 450mV respectively The amplitude control multiplier U702 has linearity problem Checked at full 1 2 and 1 4 scale Message Status Value Meaning AD Offs Err 8 AD Gain Err 8 Cal Data Err 4 Code Err XX 2 CPU Error 1 DAC OFF Err 10 DDS DAC 1 Er 4 DDS DAC 2 Er 4 DDS DAC 3 Er 4 scale Doubler Error 12 Fn Data Err x 5 Func DAC Err 10 Func Off Err 10 Gain Ctl Err 10 Gain FS Err 8 Amplitude control DACs U109B and U412A full scale output is gt 20 from nominal note this error can be caused by a signal being applied to the ex ternal AM input EE Troubleshoot g lls Gain Off Err 8 Amplitude control DAC s U109B and U412A have excessive DC offset gt 100mV Offset G Error 9 The DC offset function gain is more than 10 from nominal Can be a problem with DAC or output amplifier Offset O Err 9 Output has excessive DC offset when set to 0 gt 100mV Can be a problem with offset control or output amplifier Out Gain Err 10 Full scale output is more than 30 from nominal Can be due to incorrectly set waveform DAC reference voltage VR500 should output 1 00V bad Bessel filter bad amplitude control multiplier or output amplifier problem Prg Data Err 6 Read write test of modulation RAM U301 failed Can be bad RAM ASIC or bus problem Sync Cpr Err 12 Sync generator does not produce full scale output Sys Data Err 3 CPU RAM U204 failed read write
40. in a waveform If the point number is set to a value greater than the maximum where there is no data an edit error will result Also if the waveform has fewer than 8 points the re maining points will automatically be filled with zeroes to bring the number of output points to 8 Point Value Each point may have an amplitude value ranging between 2048 and 2047 12 bit DAC If a point has no value before a value has been entered for ex ample the data will be displayed as five dashes Adding a point to the end of the waveform To add a point to the end of a waveform set the point number to the last point 1 The value will be displayed as prior to entering a value Enter a new value for the point value Deleting a Point To delete a point enter the point number to be removed Then with the point number active flashing press CLR The remaining points will automatically be renumbered as necessary Duplicating a Point To duplicate a point enter the point number to be copied While the point number is active flashing press any UNITS key The point will be duplicated and the point number incremented to display the new point Inserting a Point To insert a point in the middle of a waveform duplicate the point currently at the insertion point It is easy to modify this new point to the desired value 2 30 Arbitrary Waveform Editing ay POINT EDIT EXAMPLE The following is a step by step example for creating a
41. is the starting point number of the segment The second is the length of the segment in points and the third is the 7 3 Redraw Mirror Amplitude Waveform menu Sine Square Triangle Saw Exponential Damped Sine Pulse Math ES Arbitrary Waveform Composer is DC value in Volts to which the segment should be set The segment can be as short as one point and as long as the whole waveform Redraws the waveform and zooms out to display the full waveform Mirrors the waveform about 0 Volts multiplies every data point by 1 Sets the amplitude of the waveform Any value in the range 0 01 Vpp to 10 Vpp may be entered To add an offset to the waveform the Math selection in the waveform menu should be used Note that V peal Val lt 5 V This command only changes the data in AWC s waveform database The waveform must be reloaded into the DS345 for the change to take effect The Waveform menu is the key to creating new waveforms and modifying existing ones Seven conventional waveforms can be created Sine Square Triangle Saw Exponential Exponentially Damped Sine wave and Pulses The Math menu allows the user to perform math operations on any waveform on the screen All waveforms are created with zero DC offset An offset may be added to the waveform using the math function Waveform creation may be aborted by pressing escape ESC on the keyboard Three parameters must be entered for these waveforms The wavefo
42. keys If the vertex num ber is set past the end of the waveform where there is no data an edit er ror will result x Value The vertex x value is the location of the vertex in waveform RAM This value may range from 0 to 16299 Each vertex must have a x value equal to or greater than that of the previous vertex and if two or more vertices have the same x value only the first is loaded the rest are ignored If the first vertex of the waveform does not have an x value of O the start of memory the DS345 will automatically add a vertex at 0 0 If the x value has no data be fore a value has been entered for example the data will be displayed as five y Value Each vertex may have an amplitude value ranging between 2048 and 2047 12 bit DAC If a vertex has no value before a value has been entered the data will be displayed as five dashes Adding a vertex at the end of the waveform To add a vertex at the end of the waveform set the vertex number to the last vertex 1 vertex 4 for example if 0 1 2 3 are filled The value will be dis played as indicating no data yet Enter a new value for either x or y If x is entered first y will be set to 0 while if y is entered first x will be set to the value of the previous vertex 0 for the first vertex Deleting a Vertex To delete a vertex enter the vertex number of the vertex to be removed Then with the vertex number active flashing press CLR The remaining vertic
43. of U202 which serves as a sampling gate The gated output at pin 4 is then filtered by R235 C220 R236 and C221 to form a control voltage to be presented to the oscillator va ractor The nominal system tuning is accomplished by the system DAC volt age via R248 D210 clamps the varactor voltage range to near ground The external timebase input and the optional internal oscillator inputs are dis criminated by ECL converters U209C and U209D respectively An external input is sensed by the voltage at the R245 C225 junction DDS ASIC AND MEMORY SHEET 3 OF 7 The DDS ASIC U300 is the heart of the DDS process The DDS ASIC is to generates the addresses for the external waveform and modulation RAM along with a few control bits The DDS process works essentially by storing a sine table in the waveform RAM and then stepping the RAM addresses in order to output the sine values to a DAC which creates the analog output The modulation RAM serves a similar purpose except it contains data and opcodes which control the internal registers in the ASIC to accomplish modu lation of the output U302 is the modulation RAM transceiver and interfaces the system processor s buffered data bus to the ASIC and modulation RAMS U303 and U304 serve a similar purpose for the waveform RAMS U312 U313 and U313 are glue logic to control writes and chip enables etc Three external chip select outputs from the ASIC WR_EXTO 1 and 2 con trol the writing of modulat
44. of errors that may occur during command exe cution command errors and execution errors For example unrecognized commands illegal queries lack of terminators and non numeric arguments are examples of command errors Execution errors are errors that occur dur ing the execution of syntactically correct commands For example out of range parameters and commands that are illegal for a particular mode of op eration are classified as execution errors No Command Bit The NO COMMAND bit in the serial poll register indicates that there no com mands waiting to be executed in the input queue This bit is reset when a complete command is received in the input queue and is set when all of the commands in the queue have been executed This bit is useful in determin ing when all of the commands sent to the DS345 have been executed This is convenient because some commands such as setting the function modu lation or autocalibration take a long time to execute and there is no other way of determining when they are done The NO COMMAND bit may be read while commands are being executed by doing a GPIB serial poll There is no way to read this bit over RS232 Note that using the STB query to read this bit will always return the value 0 because it will always return an an swer while a command is executing the STB command itself 3 2 EE Programming Commands Il DETAILED COMMAND LIST The four letter mnemonic in each command sequence specifies the c
45. phase shift gt 180 degrees Arb waveform y value out side of 2048 to 2047 range Arb waveform vertex x value lt previous ver tex x value Arb waveform vertex x value gt 16299 Cannot access GPIB and RS232 menus if option board is not installed DC output offset outside of 5V range Phase or PM deviation set outside of 7199 999 range Parameter in command is out of allowed range for that command Modulation rate out of range 0 001 Hz to 1kHz for sweeps 0 001 Hz to 10 kHz for other Trigger rate out of range 0 001Hz to 10kHz Parameter memory corrupt on power up stored setting corrupt Not a worry unless this error occurs frequently Check the battery if so Sweep or FM span set so that frequency is lt 0 Hz or gt max allowed for the current function Also if SPAN MRK function has same effect The sweep start frequency is out of range 0 lt Freq lt max for function The sweep stop frequency is out of range 0 lt Freq lt max for function The command syntax is invalid See PROGRAMMING section for correct command syntax The DS345 has detected an error on its computer interface option board Units Error Volt Error Self Test Errors es Troubleshooting il The units set with AMPL command are not Vpp Vrms or dBm The output voltage is outside of 0 01Vpp to 10Vpp range These errors may occur during the DS345 s self test In general these mes sages indicate DS345 hardware problems If th
46. point edit mode The data is just a list of the amplitude value at each waveform RAM point The program is written in C program to donwload point mode arb wf to DS345 The waveform is a simple ramp Written in icrosoft C and uses National Instrument GPIB card to be installed as DS345 in IBCONF nclude lt stdio h gt nclude lt string h gt nclude lt stdlib h gt i i i include lt dos h gt Expects DS345 include lt decl h gt National Instruments header file void main void in in ds345 data 10000 up to 10000 points void main char cmd 40 int i sum j number 3 19 HM Program Examples ee if ds345 printf Cannot find DS345 n exit 1 ibfind DS345 lt 0 open National initialize checksum initial ramp value sum 0 J 2048 number 8192 will make a 8192 point ramp for i 0 i lt number itt tali J datal i 481 j L da su if y value add to checksum data number checksum sum rintf cmd LDWF 0 d n number ds345 cmd strlen cmd Sp ibwr command to driver full scale number of points in waveform increment y value every other point increment y value if i is odd load waveform ibrd ibwrt ds345 cmd 40 read back reply befor ds345 char data long 2 number 2 sprintf
47. point format waveform We will create an 8 point waveform with the values 0 400 800 1200 0 0 0 0 Along the way we will make some mistakes that we will fix using the editing facilities To watch the waveform grow display the FUNCTION output on an oscilloscope Trigger the scope on the SYNC output 1 Press FUNCTION DOWN ARROW until ARB Set output function to ARB LED is lit 2 Press SHIFT ARB EDIT three times to dis Set point entry mode if necessary play Arb clear line then press any UNITS key 3 Press SHIFT ARB EDIT and use MODIFY Clear arb function The message arb cleared will keys to set Entry to POINT 4 Press SHIFT ARB EDIT be displayed Display edit line It should read 00000 ad Point number 0 the first point has no data 5 Press SHIFT RIGHT ARROW Then 0 Activate point value field and set y value for point UNITS zero to 0 6 Press SHIFT LEFT ARROW Then any Activate point number Duplicate point by press UNITS key ing UNITS key Point 1 now has y 0 7 Press SHIFT RIGHT ARROW then 4 0 0 Activate y value Set point 1 y value to 400 UNITS 8 Press SHIFT LEFT ARROW MODIFY UP Set display to point 2 Y value currently is ARROW We will add a point to the end of the waveform Activate point 2 y value and set to 800 9 Press SHIFT RIGHT ARROW then 8 0 0 UNITS Activate point number Duplicate point number 2 10 Press SHIFT L
48. position These cases are shown in the diagram below Case 1 Marker Start Freq lt Marker Stop Freq Figure 1 Marker Output for differ ent relationships between the marker start and stop frequencies quenci M Mrk J tk j e Sweep Stop Fre Ss D gt faa 2 ira S n Q D n Case 2 Marker Start Freq gt Marker Stop Freq Case 3 Marker Start Freq lt Sweep Start Freq 2 20 EE Modulation and Sweeps ay Marker Center and Span The markers may also be set by the center frequency and span width of the marked region Pressing SHIFT MRK CF and SHIFT MRK SPAN respec tively sets the center frequency and span The center frequency may have any value from 1 wHz to 30 2 MHz range The span may be any value such that the marker frequencies are greater than zero and less than or equal to 30 2 MHz If the span is positive the marker start position will be below the stop position while if the span is negative the marker start position will be greater than the stop position If the MODIFY keys are used to change the span pressing MODIFY UP will double the span and pressing MODIFY DOWN will divide the span in half When the center frequency is changed the span is held constant while changing the span holds the center frequen cy constant If the center frequency or span is changed such that the marker frequencies are out of the allowed range an error will be displayed Marker to Span Pressing
49. signal generator has failed 11 Doubler Error The frequency doubler has failed ATD i j The ATD query uses the DS345 A D converter to measure the voltage on analog channel i The parameter j O returns the raw data value j 1 returns the value corrected for the A D s offset and j 2 returns the value corrected for the A D s offset and gain errors 3 10 EE Programming Commands Il ATN i The ATN command sets the DS345 s output attenuators to range i The ranges go for OdB attenuation i 0 to 42dB attenuation i 7 in 6dB steps Resetting the amplitude will return the attenuators to their normal position The ATN query returns the current attenuator position FCL The FCL command recalls the factory calibration bytes This command will generate an error if calibration is not enabled MDC i The MDC command sets the mimic DAC to the value i 0 to 255 If the DS345 has modulation enabled this command will have no effect WRD 7 j k The WRD command sets the value of calibration word j to k Parameter j may have a value from 0 to 509 while k may range from 32768 to 32767 This command will generate an error if calibration is not enabled NOTE this command will alter the calibration of the the DS345 To correct the calibra tion the factory calibration bytes may be recalled see the FCL command EM Programming Commands STATUS BYTE DEFINITIONS Status Reporting The DS345 reports on its status by means of three
50. sizes Cap Tantalum SMT all case sizes Cap Ceramic 50V SMT 1206 10 X7R Cap Ceramic 50V SMT 1206 10 X7R Cap Ceramic 50V SMT 1206 10 X7R Capacitor Chip SMT1206 50V 5 NPO Cap Ceramic 50V SMT 1206 10 X7R Capacitor Chip SMT1206 50V 5 NPO Capacitor Chip SMT1206 50V 5 NPO Capacitor Chip SMT1206 50V 5 NPO Capacitor Chip SMT1206 50V 5 NPO Capacitor Chip SMT1206 50V 5 NPO Cap Ceramic 50V SMT 1206 10 X7R Cap Monolythic Ceramic 50V 20 Z5U Cap Ceramic 50V SMT 1206 10 X7R Capacitor Chip SMT1206 50V 5 NPO Cap Ceramic 50V SMT 1206 10 X7R Capacitor Chip SMT1206 50V 5 NPO Cap Monolythic Ceramic 50V 20 Z5U Cap Monolythic Ceramic 50V 20 Z5U Cap Monolythic Ceramic 50V 20 Z5U Cap Monolythic Ceramic 50V 20 Z5U 9 10 ee Component Part List i C 104 C 105 C 106 C 107 C 108 C 109 C 110 C111 C 112 C 113 C 117 C 150 C 167 C 168 C 169 C 170 C 171 C 172 C 173 C 174 C 202 C 203 C 204 C 205 C 206 C 207 C 208 C 215 C 216 C 217 C 218 C 219 C 220 C 221 C 223 C 224 C 225 C 226 C 227 C 400 C 403 C 404 C 405 C 406 C 407 C 408 C 409 C 410 C 411 C 412 5 00023 529 5 00023 529 5 00023 529 5 00023 529 5 00023 529 5 00023 529 5 00002 501 5 00002 501 5 00023 529 5 00002 501 5 00100 517 5 00023 529 5 00013 501 5 00023 529 5 00074 515 5 00023 529 5 00023 529 5 00023 529 5 00023 529 5 00023
51. sweep frequency would put the sweep frequencies either below zero or greater than that allowed for the current function Attempt to set burst count to 0 or greater than 30000 4 1 EEE Troubleshoot g lls Depth Error Edit Error Freq Error Funct Error Load Error Load CS Error Load Rng Error No Interface Offset Error Phase Error Range Error Rate Error Recall Error Span F Error Strt F Error Stop F Error Syn Error UART Error Attempt to set AM depth outside of 100 to 100 range Attempt to set front panel edit point value past end of arb waveform Can only edit the existing waveform points 1 new one Attempt to set output frequency outside of range allowed for current function set sweep markers lt 0 Hz or gt 30 2 MHz or attempting to set frequency for NOISE function Attempting to modulate NOISE attempting to download ARB modulation pat tern if not AM FM or PM or attempting sweeps FM or PM of ARB wave forms Timeout during loading of ARB waveform or modulation The can be no more than 10s between successive data points Check that the correct num ber of bytes are sent The checksum calculated by the DS345 is different than that received from the computer on downloading of ARB waveform or modulation Check that the computer is sending the correct points and calculating sum correctly Arb AM value outside of 32767 range 32768 is illegal Arb FM frequency gt 30 2 MHz Arb PM
52. test Sys G DAC Err 8 System amplitude control DAC U109B linearity error Checked at full 1 2 1 4 and 1 8 scale Trig Error X 7 Error in trigger detection circuits If x 1 triggered signal error x 2 trig ger error signal error and x 3 sweeping signal error Autocal Errors These errors messages can be generated by autocal If the DS345 fails au tocal try running the procedure again Repeated failure can indicate a hard ware problem The parameter limits and number of iteration allowed by auto cal are fixed and are set so that all units should easily calibrate within those limits The messages are listed alphabetically also listed is the status value returned by the CAL command Message Status Value Meaning AD Gain Err 3 The A D converter gain is more than 5 from nominal AD Offs Err 3 The A D converter offset is too large Bes G Cal Er 5 The DC gain of Bessel signal path is outside of 40 to 25 from nominal or the calibration did not converge after the maximum allowed number of iter ations Cal Dly Err 1 The DS345 is not warmed up Wait until warmed up for at least two minutes befor starting autocal DAC Off Err 4 The waveform DAC s output offset calibration did not converge or went out side the 50mV allowed range DBL ERR xx 6 The frequency doubler output offset calibration failed at frequency xx Out put frequency 312500 Hz xx Offset Cal Err1 4 The dc output offset control offset calibrat
53. that the correct line fuse is installed before connecting the line cord For 100V 120V use a 1 Amp fuse and for 220V 240V use a 1 2 Amp fuse LINE CORD The DS345 has a detachable three wire power cord for connection to the power source and to a protective ground The exposed metal parts of the instrument are connected to the outlet ground to protect against electrical shock Always use an outlet which has a properly connected protective ground ee Specifications Mi SPECIFICATIONS FREQUENCY RANGE OUTPUT AMPLITUDE Waveform Sine Square Ramp Triangle Noise Arbitrary Gaussian Weighting Maximum Freq Resolution 30 2 MHz 1 Hz 30 2 MHz 1 Hz 100 KHz 1 Hz 100 KHz 1 Hz 10 MHz 10 MHz 40 MHz sample rate Source Impedance 500 Output may float up to 40V AC DC relative to earth ground Range into 50Q load limited such that V peal Val lt 5 V Vi Vins dBm 509 Function Max Min Max Min Max Min Sine 10V 10 mV 3 54V 3 54 mV 23 98 36 02 Square 10V 10 mV 5V 5 mV 26 99 33 0 Triangle 10V 10 mV 2 89V 2 89 mV 22 22 37 78 Ramp 10V 10 mV 2 89V 2 89 mV 22 22 37 78 Noise 10V 10 mV 2 09V 2 09 mV 19 41 40 59 Arbitrary 10V 10 mV n a n a n a n a Resolution 3 digits DC offset OV Accuracy with OV DC Offset Sine 1uHz 100 kHz 20 MHz 30 2 MHz 10Vpp 0 2 dB 0 2dB 0 5dB 5Vpp 0 4 dB 0 4dB 0 5dB 0 01Vpp Square 1 Hz 1
54. the SYNC signal is a 25ns negative going pulse at the start of each waveform BE Function Setting FUNCTION SELECTION The DS345 s output function is selected using the FUNCTION UP DOWN ar row keys Simply press the keys until the desired function LED is lit If the programmed frequency is outside of the range allowed for the selected func tion an error message will be displayed and the frequency will be set to the maximum allowed for that function If modulation is enabled and the modula tion type or parameters are incompatible with the new function an error mes sage will be displayed and the modulation will be turned off the parameters will not be altered Ramps Ramp functions usually ramp up in voltage however downward ramps may be programmed with the output invert function see AMPLITUDE section Arbitrary Functions Arbitrary functions may be created on a computer and downloaded to the DS345 via the computer interfaces or they may be created using the DS345 s front panel editing functions Arbitrary waveforms normally repeat continuously single triggering and burst triggering of arbitrary waveforms is accomplished using the DS345 s BURST modulation function See the AR BITRARY WAVEFORM EDITING section for more detail FREQUENCY To display the DS345 s output frequency press FREQ The frequency is al ways displayed in units of Hz The DS345 has 1 wHz frequency resolution at all frequencies for all functions The maximum fr
55. the compliance of the multiplier inputs is not approached minimizing distortion For square wave outputs the DDS sine wave output is buffered by Q700 and Q701 and discriminated by comparator U704 This method is used to gener ate square waves because the DDS output cannot contain frequency compo nents higher than half of the sampling clock frequency The fast edges on the square wave output must contain very high frequency components in or der to maintain the square wave pulse shape The output of U704 is level shifted by differential pair Q702 and Q703 U703 serves as a reference for Q705 the current source for Q702 Q703 Comparator U704 always runs to provide a front panel sync output via U313F which buffers the sync signal to the bottom board Current source Q705 is shut down to disable the square wave output when not in use via Q704 which also actuates relay U700 to de select the square wave output BBS S345 Circuitry ee Component Part List i Bottom PC Board and Front Panel Parts List Ref No SRS Part No BT200 6 00001 612 C 100 5 00023 529 C 101 5 00192 542 C 102 5 00100 517 C 103 5 00192 542 C 104 5 00100 517 C 105 5 00023 529 C 106 5 00023 529 C 107 5 00023 529 C 108 5 00023 529 C 109 5 00027 503 C110 5 00125 520 C111 5 00125 520 C112 5 00201 526 C113 5 00201 526 C114 5 00100 517 C115 5 00100 517 C116 5 00192 542 C117 5 00100 517 C118 5 00100 517 C119 5 00192 542 C 120 5 00192 542 C 121 5 00100 517 C 1
56. this output is tied to that of the function out put and may be floated up to 40V relative to earth ground Marker Output This TTL compatible output goes high when the DS345 s frequency sweep passes the start marker frequency and goes low when the sweep passes the stop marker frequency The shield of this output is tied to that of the function output and may be floated up to 40V relative to earth ground Blank Lift Out This TTL compatible output is low during the upsweep of a frequency sweep and is high during the sweep retrace The shield of this output is tied to that of the function output and may be floated up to 40V relative to earth ground 4 GPIB Connector If the DS345 has the optional GPIB RS232 interface this connector is used for IEEE 488 1 and 2 compatible communications The shield of this con nector is connected to earth ground 5 RS232 Connector If the DS345 has the optional GPIB RS232 interface this connector is used for RS232 communication The DS345 is a DCE and accepts 8 bits no pari ty 2 stop bits and 300 and 19 2k Baud The shield of this connector is connected to earth ground DS345 OPERATION Introduction Power On SETTING THE FUNCTION OUTPUTS The following sections describe the operation of the DS345 The first section describes the basics of setting the function frequency amplitude and offset The second section explains sweeps and modulation The third section ex plains storing and recalling s
57. to 2V div vertical and 1ms div horizontal Trigger the scope on the falling edge of the DS345 s SWEEP output 4 The scope should show a sweep that is essentially flat The peak to peak variations should be less than 3 3 Ignore any dc variations using the peak to peak measurements for flatness comparison Output Level This test provides a visual check of the DS345 s output level control 1 Connect the DS345 s output to the oscilloscope input and terminate in 50Q 2 Set the DS345 to sine wave 1MHz 10Vpp Set the scope to 2V div verti cal and 1us div horizontal 3 Verify that the DS345 s output is about 10V pk to pk 4 Set the DS345 to 5Vpp verify the output 5 repeat step 4 at 1Vpp 0 5 Vpp 0 1 Vpp and 0 05 Vpp Adjust the scope as necessary This completes the functional tests IEE Performance Tests Ills 5 4 E Performance Tests Ml PERFORMANCE TESTS These tests are intended to measure the DS345 s conformance to its published specifications The test re sults may be recorded on the test sheet at the end of this section Allow the DS345 at least 1 2 hour to warm up run the DS345 s autocal procedure and proceed with the tests FREQUENCY ACCURACY This test measures the accuracy of the DS345 s frequency If the frequency is out of specification the DS345 s timebase frequency should be adjusted see CALIBRATION section specification 5 ppm of selected frequency 1 Turn the DS345 on and allow it to warm up
58. waveform has been generated While sending the data the message Sending data points to DS345 Please wait is displayed At the same time the DS345 should display the message loading Using the GPIB interface a 16000 point waveform takes about 7 seconds to transmit Using RS232 transfer times are longer and depend on the Baud rate After loading is complete the arbitrary wave can be observed at the output of the DS345 by selecting the ARB function from the front panel or through the trigger menu in AWC see below This selection sends an ASCII file directly from disk to the DS345 There is no processing of the file contents the user must ensure that the contents will be recognized by the DS345 A file selection box is displayed to select the proper file The ASCII file can be used to send a series of commands to the DS345 It can also be used as a macro facility to perform a series of commands on the unit Warning The ASCII File command does not perform any error checking syntax or otherwise on the commands that the user is sending to the DS345 Double checking the ASCII file is a good idea since an error could yield unpredictable results The Set DS345 menu is used to remotely set the sampling frequency of the DS345 and to set communication parameters This selection sets the DS345 s arbitrary waveform sampling frequency The selection is disabled when no waveform is displayed on the screen The frequency range is from
59. 0 47 3 48K 220 220 220 220 220 220 220 220 220 220 220 Ferrite bead SMT Ferrite bead SMT Ferrite Beads Ferrite Beads Ferrite bead SMT Inductor Axial Inductor Variable Inductor Variable Inductor Axial Inductor Axial Inductor Axial Inductor Axial Inductor Axial Inductor Axial Inductor Axial Inductor Axial Inductor Axial Ferrite Beads Ferrite Beads Inductor Axial Inductor Axial Res Network SIP 1 4W 2 Isolated Pot Multi Turn Trim 3 8 Square Top Ad Pot Multi Turn Trim 3 8 Square Top Ad Printed Circuit Board Printed Circuit Board Transistor TO 72 Package Transistor TO 92 Package Transistor TO 92 Package Transistor TO 92 Package Transistor TO 92 Package Transistor TO 92 Package Transistor TO 92 Package Transistor TO 92 Package Thick Film 5 200 ppm Chip Resistor Thick Film 5 200 ppm Chip Resistor Thick Film 5 200 ppm Chip Resistor Thick Film 5 200 ppm Chip Resistor Thin Film 1 50 ppm MELF Resistor Thick Film 5 200 ppm Chip Resistor Thick Film 5 200 ppm Chip Resistor Thick Film 5 200 ppm Chip Resistor Thick Film 5 200 ppm Chip Resistor Thick Film 5 200 ppm Chip Resistor Thick Film 5 200 ppm Chip Resistor Thick Film 5 200 ppm Chip Resistor Thick Film 5 200 ppm Chip Resistor Thick Film 5 200 ppm Chip Resistor Thick Film 5 200 ppm Chip Resistor Thick Film 5 200 ppm Chip Resistor 9
60. 0 Vpp Overshoots Square Wave Symmetry square 1 MHz 5 Vpp pulse width square 1 MHz 5 Vpp pulse width asymmetry width width AM Envelope Distortion 80 depth 1 kHz 5 13 CALIBRATION Introduction Calibration Enable Calbytes The calibration of the DS345 is composed of two parts adjustment and cali bration Adjustments are actual physical adjustments to variable resistors in ductors and capacitors to correct the DS345 s oscillator filters and output amplifier response Calibration is the process of determining the calibration constants calbytes that the DS345 firmware uses to correct the output am plitude etc The DS345 s autocal procedure automatically determines the most important of these calbytes The settings of the adjustments are in general very stable and should rarely require change If the adjustments are changed the corresponding calibra tions must be performed However the DS345 should need only routine running of the autocal procedure and occasional complete recalibration to maintain its performance The DS345 is shipped with calibration disabled When calibration is disabled only autocal is allowed and direct access to the calbytes is prevented The internal calibration enable switch must be set to enable calibration To set the switch remove the DS345 s top cover by removing its four retaining screws this will break the calibration seal On units with an optional oscilla
61. 00 kHz 20 MHz 30 2 MHz 10Vpp 3 6 15 5Vpp 5 8 18 0 01Vpp EE Specifications Triangle Ramp Arbitrary 3 gt 5Vpp 5 lt 5Vpp DC OFFSET Range 5V limited such that V speal Val lt 5 V Resolution 3 digits VAC 0 Accuracy 1 5 of setting 0 2 mV DC only 0 8 mV to 80 mV depending on AC and DC settings WAVEFORMS Sinewave Spectral Purity Spurious 45 dBc non harmonic typ Phase Noise 55 dBc in a 30 KHz band centered on the carrier exclusive of discrete spurious signals typ Subharmonic lt 50 dBc Harmonic Distortion Harmonically related signals will be less than Level Frequency Range lt 55 dBc DC to 100 KHz lt 45 dBc 1 to1 MHz lt 35 dBc 1 to10 MHz lt 25 dBc 10 to30 MHz Square Wave Rise Fall Time lt 15 nS 10 to 90 at full output Asymmetry lt 1 of period 4nS Overshoot lt 5 of peak to peak amplitude at full output Ramps Triangle and Arbitrary Rise Fall Time 35 nS 10 MHz Bessel Filter Linearity 0 5 of full scale output Settling Time lt 1 us to settle within 0 1 of final value at full output Arbitrary Function Sample Rate 40 MHZ N N 1 to 2 1 Memory Length 8 to 16 300 points Resolution 12 bits 0 025 of full scale PHASE Range 7199 999 with respect to arbitrary starting phase Resolution 0 001 AMPLITUDE MODULATION Source Internal sine square triangle or ramp or External
62. 00143 101 TEST JACK Vertical Test Jack JP100 1 00166 130 60 PIN DIL Connector Male JP101 1 00065 114 7 PIN WHITE Header Amp MTA 100 JP102 1 00065 114 7 PIN WHITE Header Amp MTA 100 L1 6 00236 631 FR47 Ferrite bead SMT 9 14 ees Component Part List i L2 L3 L4 L4A L5 L 202 L 203 L 204 L 205 L 206 L 400 L 401 L 402 L 403 L 404 L 405 L 406 L 500 L 601 L 603 L 604 N 600 P 700 P 701 PC1 PC2 Q 203 Q 604 Q 700 Q 701 Q 702 Q 703 Q 704 Q 705 R1 R2 R3 R4 R5 R7 R8 R9 R10 R11 R 12 R13 R 14 R15 R 16 R17 6 00236 631 6 00236 631 6 00416 630 6 00416 630 6 00236 631 6 00108 603 6 001 12 606 6 00106 606 6 00124 603 6 00048 603 6 001 16 603 6 001 15 603 6 00117 603 6 00118 603 6 00116 603 6 001 15 603 6 001 15 603 6 00055 630 6 00055 630 6 00122 603 6 00122 603 4 00717 421 4 00011 441 4 00013 441 7 00365 701 7 00819 701 3 00018 324 3 00022 325 3 00021 325 3 00021 325 3 00022 325 3 00022 325 3 00022 325 3 00022 325 4 01455 461 4 01455 461 4 01461 461 4 01447 461 4 01169 462 4 01463 461 4 01463 461 4 01463 461 4 01463 461 4 01463 461 4 01463 461 4 01463 461 4 01463 461 4 01463 461 4 01463 461 4 01463 461 FR47 FR47 FR73 FR73 FR47 2 2UH 47UH 1 0UH 7KMM 68UH 4 7UH 3 3MH 6 8MH 2 2MH 4 7MH 3 3MH 6 8MH 6 8MH FB43 1801 FB43 1801 82UH 82UH 22X4 10K 50K DS345 TOP DDS FIX MRF904 2N3906 2N3904 2N3904 2N3906 2N3906 2N3906 2N3906 100 100 18
63. 01 1 0K Resistor Carbon Film 1 4W 5 R633 4 00021 401 1 0K Resistor Carbon Film 1 4W 5 R634 4 00743 407 536 Resistor Metal Film 1 8W 1 50PPM R635 4 00483 407 1 05K Resistor Metal Film 1 8W 1 50PPM R636 4 00427 449 49 9 Resistor Metal Film 1 2W 1 50ppm R637 4 00217 408 1 000K Resistor Metal Film 1 8W 0 1 25ppm R638 4 00217 408 1 000K Resistor Metal Film 1 8W 0 1 25ppm R639 4 00370 441 500 Pot Multi Turn Trim 3 8 Square Top Ad R640 4 00034 401 10K Resistor Carbon Film 1 4W 5 R 641 4 00149 407 121 Resistor Metal Film 1 8W 1 50PPM R642 4 00522 407 243 Resistor Metal Film 1 8W 1 50PPM R643 4 00525 407 7 50 100PPM Resistor Metal Film 1 8W 1 50PPM R644 4 00525 407 7 50 100PPM Resistor Metal Film 1 8W 1 50PPM R645 4 00051 401 2 7K Resistor Carbon Film 1 4W 5 R646 4 00083 401 47K Resistor Carbon Film 1 4W 5 R647 4 00083 401 47K Resistor Carbon Film 1 4W 5 R648 4 00130 407 1 00K Resistor Metal Film 1 8W 1 50PPM R649 4 00130 407 1 00K Resistor Metal Film 1 8W 1 50PPM R 701 4 00708 449 150 Resistor Metal Film 1 2W 1 50ppm R702 4 00709 449 37 4 Resistor Metal Film 1 2W 1 50ppm R703 4 00708 449 150 Resistor Metal Film 1 2W 1 50ppm R 704 4 00710 449 165 Resistor Metal Film 1 2W 1 50ppm R705 4 00710 449 165 Resistor Metal Film 1 2W 1 50ppm R 706 4 00711 449 93 1 Resistor Metal Film 1 2W 1 50ppm R707 4 00710 449 165 Resistor Metal Film 1 2W 1 50ppm R70
64. 04 301 1N4148 Diode D202 3 00203 301 1N5711 Diode D203 3 00004 301 1N4148 Diode D601 3 00293 301 1N5226B Diode D602 3 00004 301 1N4148 Diode D603 3 00004 301 1N4148 Diode D604 3 00198 301 1N5231B Diode D605 3 00198 301 1N5231B Diode J1 1 00038 130 40 PIN DIL Connector Male J 300 1 00038 130 40 PIN DIL Connector Male J 401 1 00003 120 BNC Connector BNC J 402 1 00003 120 BNC Connector BNC J 403 1 00003 120 BNC Connector BNC J 404 1 00003 120 BNC Connector BNC J 405 1 00003 120 BNC Connector BNC J 600 1 00003 120 BNC Connector BNC J 601 1 00003 120 BNC Connector BNC J 602 1 00003 120 BNC Connector BNC J 700 1 00003 120 BNC Connector BNC JP401 1 00166 130 60 PIN DIL Connector Male JP500 1 00037 130 16 PIN DIL Connector Male K 701 3 00422 335 RG2ET DC5V Relay K 702 3 00422 335 RG2ET DC5V Relay K 703 3 00422 335 RG2ET DC5V Relay L400 6 00055 630 FB43 1801 Ferrite Beads L 401 6 00055 630 FB43 1801 Ferrite Beads L700 6 00055 630 FB43 1801 Ferrite Beads N200 4 00334 425 10KX5 Resistor Network SIP 1 4W 2 Common N300 4 00420 420 390X8 Resistor Network DIP 1 4W 2 8 Ind N 301 4 00420 420 390X8 Resistor Network DIP 1 4W 2 8 Ind N302 4 00289 420 470X8 Resistor Network DIP 1 4W 2 8 Ind N 303 4 00551 420 12X8 Resistor Network DIP 1 4W 2 8 Ind N 304 4 00707 425 2 2KX7 Resistor Network SIP 1 4W 2 Common N400 4 00255 421 100X3 Res Network SIP 1 4W 2 Isolated N 401 4 00255 421 100X3 Res Netw
65. 06 C 607 C 608 C 609 C 610 C 611 C 612 C 613 C 614 C 615 C 616 C 617 C 618 C 619 C 620 C 700 C 701 CU516 D1 D2 D3 D4 5 00262 548 5 00262 548 5 00262 548 5 00262 548 5 00262 548 5 00262 548 5 00262 548 5 00192 542 5 00262 548 5 00262 548 5 00262 548 5 00262 548 5 00262 548 5 00262 548 5 00066 513 5 00023 529 5 00040 509 5 00192 542 5 00027 503 5 00100 517 5 00027 503 5 00100 517 5 00002 501 5 00022 501 5 00022 501 5 00023 529 5 00023 529 5 00022 501 5 00023 529 5 00098 517 5 00023 529 5 00023 529 5 00023 529 5 00106 530 5 00023 529 5 00172 544 5 00098 517 5 00023 529 5 00172 544 5 00098 517 5 00098 517 5 00074 515 5 00074 515 5 00023 529 5 00100 517 5 00016 501 3 00012 306 3 00012 306 3 00012 306 3 00012 306 01U AXIAL 01U AXIAL 01U AXIAL 01U AXIAL 01U AXIAL 01U AXIAL 01U AXIAL 22U MIN 01U AXIAL 01U AXIAL 01U AXIAL 01U AXIAL 01U AXIAL 01U AXIAL 022U 1U 1 0U 22U MIN 01U 2 2U 01U 2 2U 100P 001U 001U 1U 1U 001U 1U 10U 1U 1U 1U 9 0 50P 1U 1000U 10U 1U 1000U 10U 10U 015U 015U 1U 2 2U 470P GREEN GREEN GREEN GREEN Capacitor Ceramic 50V 80 20 Z5U AX Capacitor Ceramic 50V 80 20 Z5U AX Capacitor Ceramic 50V 80 20 Z5U AX Capacitor Ceramic 50V 80 20 Z5U AX Capacitor Ceramic 50V 80 20 Z5U AX Capacitor Ceramic 50V 80 20 Z5U AX Capacitor Ceramic 50V 80 20 Z5U AX Cap
66. 1 50PPM Resistor Metal Film 1 8W 1 50PPM Resistor Metal Film 1 8W 1 50PPM Resistor Metal Film 1 8W 1 50PPM Resistor Metal Film 1 8W 1 50PPM Resistor Carbon Film 1 4W 5 Resistor Metal Film 1 8W 1 50PPM Resistor Metal Film 1 8W 1 50PPM Resistor Carbon Film 1 4W 5 Resistor Carbon Film 1 4W 5 Resistor Carbon Film 1 4W 5 Resistor Carbon Film 1 4W 5 Resistor Carbon Film 1 4W 5 Resistor Carbon Film 1 4W 5 Resistor Carbon Film 1 4W 5 Resistor Carbon Film 1 4W 5 Resistor Carbon Film 1 4W 5 Resistor Carbon Film 1 4W 5 Resistor Metal Film 1 8W 1 50PPM Resistor Metal Film 1 8W 1 50PPM Resistor Metal Film 1 8W 1 50PPM Resistor Metal Film 1 8W 1 50PPM Resistor Carbon Film 1 4W 5 Resistor Metal Film 1 8W 1 50PPM Socket THRU HOLE Transformer Inductor Inductor Inductor Inductor Inductor Inductor Inductor Inductor Inductor Inductor Integrated Circuit Surface Mount Pkg Integrated Circuit Surface Mount Pkg Integrated Circuit Thru hole Pkg Integrated Circuit Thru hole Pkg Integrated Circuit Thru hole Pkg Integrated Circuit Thru hole Pkg Integrated Circuit Thru hole Pkg Integrated Circuit Thru hole Pkg Integrated Circuit Thru hole Pkg Integrated Circuit Thru hole Pkg Integrated Circuit Thru hole Pkg a ee ee ee eae ee 9 19 EE Component Part List U 110 U 111 U 200 U 201 U 202 U 205 U 206 U 207 U
67. 1 390 Resistor Carbon Film 1 4W 5 R 503 4 00076 401 390 Resistor Carbon Film 1 4W 5 R 504 4 00076 401 390 Resistor Carbon Film 1 4W 5 R505 4 00076 401 390 Resistor Carbon Film 1 4W 5 R 506 4 00076 401 390 Resistor Carbon Film 1 4W 5 R 507 4 00081 401 470 Resistor Carbon Film 1 4W 5 R 508 4 00081 401 470 Resistor Carbon Film 1 4W 5 R 509 4 00081 401 470 Resistor Carbon Film 1 4W 5 R 510 4 00081 401 470 Resistor Carbon Film 1 4W 5 R511 4 00081 401 470 Resistor Carbon Film 1 4W 5 R 512 4 00034 401 10K Resistor Carbon Film 1 4W 5 R513 4 00034 401 10K Resistor Carbon Film 1 4W 5 R514 4 00034 401 10K Resistor Carbon Film 1 4W 5 U 500 3 00645 340 NAT9914BPD Integrated Circuit Thru hole Pkg U 501 3 00078 340 DS75160A Integrated Circuit Thru hole Pkg U 502 3 00079 340 DS75161A Integrated Circuit Thru hole Pkg U 503 3 0035 1 340 74HCT299 Integrated Circuit Thru hole Pkg U 504 3 00303 340 74HC164 Integrated Circuit Thru hole Pkg U 505 3 00040 340 74HC157 Integrated Circuit Thru hole Pkg U 506 3 00333 340 74HC161 Integrated Circuit Thru hole Pkg U 512 3 00217 340 MAX232 Integrated Circuit Thru hole Pkg U 513 3 00155 340 74HC04 Integrated Circuit Thru hole Pkg U 514 3 00036 340 74HC00 Integrated Circuit Thru hole Pkg U 515 3 00049 340 74HC74 Integrated Circuit Thru hole Pkg 9 21 EE Component Part List U 516 U 517 U 518 U 519 U 520 U 521 U 522 U 523 Zo
68. 100kHz 1MHz 10 MHz 20MHz and 30MHz Record the results and verify that the offset is between 80mV and 80mV at all of the frequencies This test measures the subharmonic content of the DS345 s sinewave out put This is residual carrier feedthrough from the DS345 s frequency doubler The frequencies in this test are picked such that spurious frequencies from the DDS process do not fall on the carrier position specification lt 50 dBc 1 Connect the DS345 to the RF spectrum analyzer Set the DS345 to sine wave 23 98dBm 10Vpp OV offset 2 Set the DS345 to to 102 kHz Set the spectrum analyzer to 51 kHz center frequency 10 kHz span The carrier amplitude at 51 kHz should be less than 26 02 dBm Record the result 5 7 HMI Performance Tests Ills 3 Set the DS345 to 1 002 MHz and the spectrum analyzer to 501 kHz Measure and record the amplitude of the 501 kHz carrier It should be less that 26 02 dBm 4 Repeat step 3 with the DS345 and spectrum analyzer set to the following frequencies 10 002 MHz and 5 001 MHz 20 002 MHz and 10 001 MHz and 30 002 MHz and 15 001 MHz Record the results and verify that the carrier levels are below 26 02 dBm SPURIOUS SIGNALS These tests measure the spurious signals on the DS345 s sine wave outputs They check both close in and wide band spurs specification lt 45 dBc at full output 1 Connect the DS345 to the RF spectrum analyzer Set the DS345 to sine wave 23 98dBm 10V
69. 18 8 SS BNC BUSHING 4 40 HINGED SOLDR SLV RG174 4 CLAMP 30 1 8 DRILL TO 220 8 1 4 18 8 32X3 8PF 7 PIN 24AWG WH Integrated Circuit Integrated Circuit Integrated Circuit Integrated Circuit Thru hole Pkg Integrated Circuit Thru hole Pkg Integrated Circuit Thru hole Pkg Integrated Circuit Thru hole Pkg Voltage Reg TO 220 TAB Package Voltage Reg TO 220 TAB Package Varistor Zinc Oxide Nonlinear Resistor Power Entry Hardware Power Entry Hardware Lugs Nut Kep Nut Kep Termination Tie Washer Split Wire 18 UL1007 Stripped 3 8x3 8 No Tin Screw Black All Types Grommet Heat Sinks Insulators Screw Panhead Phillips Screw Flathead Phillips Screw Panhead Phillips Washer nylon Hardware Misc Power Button Screw Black All Types Screw Panhead Phillips Insulators Screw Panhead Phillips Screw Panhead Phillips Washer nylon Screw Panhead Phillips Wire 22 UL1007 Wire 22 UL1007 Screw Allen Head Hardware Misc Washer Flat Insulators Standoff Termination Tie Hardware Misc Heat Sinks Wire 18 UL1015 Strip 3 8 x 3 8 No Tin Screw Black All Types Connector Amp MTA 100 Thru hole Pkg Thru hole Pkg Thru hole Pkg 9 9 EE Component Part List Zo Zo Zo Zo Zo Zo Zo Zo Zo Zo Zo Zo Zo Zo Zo Zo Zo Zo Zo Zo Zo Zo Z 100 1 00073 120 1 00133 171 1 00161 171 1 00163 130 1 00172 170 4 00541 435 6 00004 611 6 00099 622 6 001
70. 19 614 6 00120 630 7 00194 715 7 00257 720 7 00258 720 7 00343 709 7 00344 720 7 00345 720 7 00347 720 7 00348 720 7 00440 701 7 00680 720 7 00721 709 9 00458 917 0 00158 070 INSL 40 COND 60 COND 5 PIN SI 9535 130V 1200A 1A 3AG 10 MHZ MINI FT82 77 FB64 101 PS300 38 SR560 20 SR560 26 DS345 2 DS345 9 DS345 10 DS345 12 13 DS345 14 DS345 RR PANEL PS300 52 DS345 19 DS335 340 345 60MM 24V Top PC Board Parts List Ref No SRS Part No C1 5 00472 569 C2 5 00472 569 C3 5 00299 568 C4 5 00299 568 C5 5 00299 568 C6 5 00387 552 C7 5 00299 568 C8 5 00387 552 c9 5 00375 552 C 10 5 00375 552 C11 5 00365 552 C12 5 00365 552 C13 5 00299 568 C15 5 00023 529 C 16 5 00299 568 C17 5 00387 552 C18 5 00299 568 C19 5 00387 552 C 100 5 00023 529 C 101 5 00023 529 C 102 5 00023 529 C 103 5 00023 529 Value 4 7U T35 4 7U T35 1U 1U 1U 1000P 1U 1000P 100P 100P 15P 15P 1U 1U 1U 1000P 1U 1000P 1U 1U 1U 1U Connector BNC Cable Assembly Ribbon Cable Assembly Ribbon Connector Male Cable Assembly Multiconductor Varistor Zinc Oxide Nonlinear Resistor Fuse Ovenized Crystal Oscillator Iron Powder Core Ferrite Beads Bracket Fabricated Part Fabricated Part Lexan Overlay Fabricated Part Fabricated Part Fabricated Part Fabricated Part Printed Circuit Board Fabricated Part Lexan Overlay Product Labels Fans amp Hardware Description Cap Tantalum SMT all case
71. 22 5 00100 517 C 123 5 00100 517 C 124 5 00192 542 C 125 5 00100 517 C 126 5 00030 520 C 127 5 00262 548 C 128 5 00262 548 C 129 5 00262 548 C 130 5 00262 548 C 131 5 00262 548 C 132 5 00262 548 C 133 5 00262 548 C 134 5 00262 548 C 135 5 00262 548 C 136 5 00262 548 C 137 5 00262 548 C 138 5 00262 548 C 139 5 00262 548 C 140 5 00262 548 C 141 5 00262 548 C 142 5 00262 548 C 143 5 00262 548 C 144 5 00262 548 C 145 5 00262 548 Value BR 2 3A 2PIN PC 1U 22U MIN 2 2U 22U MIN 2 2U 1U 1U 1U 1U 01U 12000U 12000U 2200U 2200U 2 2U 2 2U 22U MIN 2 2U 2 2U 22U MIN 22U MIN 2 2U 2 2U 2 2U 22U MIN 2 2U 2200U 01U AXIAL 01U AXIAL 01U AXIAL 01U AXIAL 01U AXIAL 01U AXIAL 01U AXIAL 01U AXIAL 01U AXIAL 01U AXIAL 01U AXIAL 01U AXIAL 01U AXIAL 01U AXIAL 01U AXIAL 01U AXIAL 01U AXIAL 01U AXIAL 01U AXIAL Description Battery Cap Monolythic Ceramic 50V 20 Z5U Cap Mini Electrolytic 50V 20 Radial Capacitor Tantalum 35V 20 Rad Cap Mini Electrolytic 50V 20 Radial Capacitor Tantalum 35V 20 Rad Cap Monolythic Ceramic 50V 20 Z5U Cap Monolythic Ceramic 50V 20 Z5U Cap Monolythic Ceramic 50V 20 Z5U Cap Monolythic Ceramic 50V 20 Z5U Capacitor Ceramic Disc 50V 20 Z5U Capacitor Electrolytic 16V 20 Rad Capacitor Electrolytic 16V 20 Rad Capacitor Electrolytic 35V 20 Rad Capacitor Electrolytic 35V 20 Rad Capacitor
72. 345 Communications GPIB Communication RS 232 Communication Data Window Command Syntax Detailed Command List Function Output Commands Modulation Control Arb Waveform and Modulation Setup Control Commands Status Reporting Commands Test and Calibration Commands Status Byte Definitions Programming Examples Arbitrary AM Modulation Arbitrary FM Modulation Arbitrary PM Modulation Point Mode Arb Waveform Vector Mode Arb Waveform Test and Calibration Troubleshooting Operation Error Messages Self Test Error Messages Autocal Error Messages Performance Tests Necessary Equipment Functional Tests Front Panel Test Self Tests Sine Wave Square Wave Amplitude Flatness Output Level 3 10 3 12 3 15 3 16 3 17 3 18 3 19 3 20 4 1 4 1 4 3 4 4 Performance Tests Frequency Accuracy Amplitude Accuracy DC Offset Accuracy Subharmonics Spurious Signals Harmonic Distortion Phase Noise Square Wave Rise Time Square Wave Symmetry AM Envelope Distortion Test Scorecard Calibration Introduction Calibration Enable Calbytes Necessary Equipment Adjustments Clock Adjustment DAC Reference Voltage Output Amplifier Bandwidth Bessel Filter Adjustment Harmonic Distortion Calibration 5 00 V Reference Clock Calibration Attenuator Calibration Carrier Null Calibration Sinewave Amplitude Square Wave Amplitude Square Wave Symmetry Arbitrary Waveform Software Introduction Installing AWC Getting Started with AWC Har
73. 50PPM R 623 4 00188 407 4 99K Resistor Metal Film 1 8W 1 50PPM R 624 4 00191 407 49 9 Resistor Metal Film 1 8W 1 50PPM R 625 4 00191 407 49 9 Resistor Metal Film 1 8W 1 50PPM R 626 4 00719 401 4 7 Resistor Carbon Film 1 4W 5 R 627 4 00719 401 4 7 Resistor Carbon Film 1 4W 5 R 628 4 00734 407 118 Resistor Metal Film 1 8W 1 50PPM R 629 4 00720 407 115 Resistor Metal Film 1 8W 1 50PPM R 630 4 00185 407 4 02K Resistor Metal Film 1 8W 1 50PPM R 631 4 00031 401 100 Resistor Carbon Film 1 4W 5 R 632 4 00031 401 100 Resistor Carbon Film 1 4W 5 R 633 4 00031 401 100 Resistor Carbon Film 1 4W 5 R 634 4 00031 401 100 Resistor Carbon Film 1 4W 5 R 700 4 00215 407 909 Resistor Metal Film 1 8W 1 50PPM R 701 4 00215 407 909 Resistor Metal Film 1 8W 1 50PPM R 702 4 00141 407 100 Resistor Metal Film 1 8W 1 50PPM R 703 4 00141 407 100 Resistor Metal Film 1 8W 1 50PPM R 704 4 00081 401 470 Resistor Carbon Film 1 4W 5 R 705 4 00081 401 470 Resistor Carbon Film 1 4W 5 R 706 4 00685 408 100 Resistor Metal Film 1 8W 0 1 25ppm R 707 4 00685 408 100 Resistor Metal Film 1 8W 0 1 25ppm R 708 4 00081 401 470 Resistor Carbon Film 1 4W 5 R 709 4 00081 401 470 Resistor Carbon Film 1 4W 5 R710 4 00217 408 1 000K Resistor Metal Film 1 8W 0 1 25ppm R711 4 00217 408 1 000K Resistor Metal Film 1 8W 0 1 25ppm 9 18 eee Component Part List i R712 R713 R714 R715
74. 529 5 00179 532 5 00027 503 5 00179 532 5 00027 503 5 00027 503 5 00008 501 5 00250 532 5 00023 529 5 00100 517 5 00002 501 5 00016 501 5 00132 501 5 00002 501 5 00023 529 5 00023 529 5 00023 529 5 00027 503 5 00023 529 5 00061 513 5 00008 501 5 00151 501 5 00063 513 5 00261 513 5 00263 513 5 00064 513 5 00074 515 5 00013 501 5 00013 501 5 00013 501 5 00002 501 1U 1U 1U 1U 1U 1U 100P 100P 1U 100P 2 2U 1U 33P 1U 015U 1U 1U 1U 1U 1U 15P 01U 15P 01U 01U 22P 82P 1U 2 2U 100P 470P 56P 100P 1U 1U 1U 01U 1U 001U 22P 680P 0033U 0056U 0012U 0047U 015U 33P 33P 33P 100P Cap Monolythic Ceramic 50V 20 Z5U Cap Monolythic Ceramic 50V 20 Z5U Cap Monolythic Ceramic 50V 20 Z5U Cap Monolythic Ceramic 50V 20 Z5U Cap Monolythic Ceramic 50V 20 Z5U Cap Monolythic Ceramic 50V 20 Z5U Capacitor Ceramic Disc 50V 10 SL Capacitor Ceramic Disc 50V 10 SL Cap Monolythic Ceramic 50V 20 Z5U Capacitor Ceramic Disc 50V 10 SL Capacitor Tantalum 35V 20 Rad Cap Monolythic Ceramic 50V 20 Z5U Capacitor Ceramic Disc 50V 10 SL Cap Monolythic Ceramic 50V 20 Z5U Capacitor Mylar Poly 50V 10 Rad Cap Monolythic Ceramic 50V 20 Z5U Cap Monolythic Ceramic 50V 20 Z5U Cap Monolythic Ceramic 50V 20 Z5U Cap Monolythic Ceramic 50V 20 Z5U Cap Monolythic Ceramic 50V 20 Z5U Capacitor Ceramic Disc 50V
75. 7 The checksum is the 16 bit sum of the j words sent in point mode or the 2 j words sent in vector mode 3 8 EE Programming Commands Il Setup Control Commands IDN The IDN common query returns the DS345 s device configuration This string is in the format StanfordResearchSystems DS345 serial num ber version number Where serial number is the five digit serial number of the particular unit and version number is the 3 digit firmware version num ber RCL i The RCL command recalls stored setting number i where i may range from O to 9 If the stored setting is corrupt or has never been stored an execution error will be generated RST The RST common command resets the DS345 to its default configurations SAV i The SAV command saves the current instrument settings as setting number i Status Reporting Commands See tables at the end of the Programming section for Status Byte definitions CLS The CLS common command clears all status registers This command does not affect the status enable registers ESE i The ESE command sets the standard event status byte enable register to the decimal value i ESR i The ESR common command reads the value of the standard event status register If the parameter i is present the value of bit i is returned 0 or 1 Reading this register will clear it while reading bit i will clear just bit i PSC i The PSC common command sets the value of the power on status clear
76. 8 2 1987 standard Before attempting to communicate with the DS345 over the GPIB interface the DS345 s device address must be set The address is set in the second line of the GPIB menu type SHIFT GPIB twice and can be set between 0 and 30 The DS345 is configured as a DCE transmit on pin 3 receive on pin 2 and supports CTS DTR hardware handshaking The CTS signal pin 5 is an out put indicating that the DS345 is ready while the DTR signal pin 20 is an in put that is used to control the DS345 s transmitting If desired the handshake pins may be ignored and a simple 3 wire interface pins 2 3 and 7 may be used The RS232 interface baud rate may be set in the second line of the RS232 menu type SHIFT RS232 twice The interface is fixed at 8 data bits no parity and 2 stop bits To assist in programming the DS345 has 3 front panel status LEDs The ACT LED flashes whenever a character is received or sent over either inter face The ERR LED flashes when an error has been detected such as an il legal command or an out of range parameter The REM LED is lit whenever the DS345 is in a remote state front panel locked out To help find program errors the DS345 has an input data window which dis plays the data received over either the GPIB or RS232 interfaces This win dow is the DATA menu and displays the received data in hexadecimal for mat Scroll back and forth through the last 256 characters received using the MODIFY u
77. 8 4 00710 449 165 Resistor Metal Film 1 2W 1 50ppm R 709 4 00712 449 113 Resistor Metal Film 1 2W 1 50ppm R710 4 00712 449 113 Resistor Metal Film 1 2W 1 50ppm 9 7 EE Component Part List R711 4 00713 407 392 Resistor Metal Film 1 8W 1 50PPM R712 4 00712 449 113 Resistor Metal Film 1 2W 1 50ppm R713 4 00712 449 113 Resistor Metal Film 1 2W 1 50ppm S300 6 00096 600 MINI Misc Components 0202 1 00026 150 28 PIN 600 MIL Socket THRU HOLE Swi 7 00340 740 DS345 1 Keypad Conductive Rubber SW10 0 2 00023 218 DPDT Switch Panel Mount Power Rocker SW30 0 2 00008 207 SPSTX4 Switch DIP T100 6 00092 610 DS345 Transformer U1 3 00290 340 HDSP A101 Integrated Circuit Thru hole Pkg U2 3 00290 340 HDSP A101 Integrated Circuit Thru hole Pkg U3 3 00290 340 HDSP A101 Integrated Circuit Thru hole Pkg U4 3 00290 340 HDSP A101 Integrated Circuit Thru hole Pkg U5 3 00290 340 HDSP A101 Integrated Circuit Thru hole Pkg U6 3 00290 340 HDSP A101 Integrated Circuit Thru hole Pkg U7 3 00290 340 HDSP A101 Integrated Circuit Thru hole Pkg U8 3 00290 340 HDSP A101 Integrated Circuit Thru hole Pkg U9 3 00290 340 HDSP A101 Integrated Circuit Thru hole Pkg U 10 3 00290 340 HDSP A101 Integrated Circuit Thru hole Pkg U 11 3 00290 340 HDSP A101 Integrated Circuit Thru hole Pkg U 12 3 00290 340 HDSP A101 Integrated Circuit Thru hole Pkg U 100 3 00114 329 7815 Voltage Reg TO 220 TAB Package U 101 3
78. 8 614 T37 6 Iron Powder Core Optional PC Board Parts List Ref No SRS Part No Value Description C 500 5 00192 542 22U MIN Cap Mini Electrolytic 50V 20 Radial C 501 5 00010 501 270P Capacitor Ceramic Disc 50V 10 SL C502 5 00023 529 1U Cap Monolythic Ceramic 50V 20 Z5U C503 5 00023 529 1U Cap Monolythic Ceramic 50V 20 Z5U C504 5 00023 529 1U Cap Monolythic Ceramic 50V 20 Z5U C505 5 00023 529 1U Cap Monolythic Ceramic 50V 20 Z5U C506 5 00023 529 1U Cap Monolythic Ceramic 50V 20 Z5U C507 5 00023 529 1U Cap Monolythic Ceramic 50V 20 Z5U C508 5 00023 529 1U Cap Monolythic Ceramic 50V 20 Z5U C 509 5 00192 542 22U MIN Cap Mini Electrolytic 50V 20 Radial C510 5 00192 542 22U MIN Cap Mini Electrolytic 50V 20 Radial C511 5 00192 542 22U MIN Cap Mini Electrolytic 50V 20 Radial C512 5 00192 542 22U MIN Cap Mini Electrolytic 50V 20 Radial C513 5 00023 529 1U Cap Monolythic Ceramic 50V 20 Z5U C514 5 00023 529 1U Cap Monolythic Ceramic 50V 20 Z5U C515 5 00023 529 1U Cap Monolythic Ceramic 50V 20 Z5U C516 5 00023 529 1U Cap Monolythic Ceramic 50V 20 Z5U C517 5 00023 529 1U Cap Monolythic Ceramic 50V 20 Z5U J 500 1 00238 161 GPIB SHIELDED Connector IEEE488 Reverse R A Female P 500 1 00016 160 RS232 25 PIN D Connector D Sub Right Angle PC Female R 500 4 00021 401 1 0K Resistor Carbon Film 1 4W 5 R 501 4 00021 401 1 0K Resistor Carbon Film 1 4W 5 R502 4 00076 40
79. 953 Resistor Metal Film 1 8W 1 50PPM R 447 4 00239 407 953 Resistor Metal Film 1 8W 1 50PPM R 600 4 00204 407 750 Resistor Metal Film 1 8W 1 50PPM R 601 4 00204 407 750 Resistor Metal Film 1 8W 1 50PPM R 602 4 00141 407 100 Resistor Metal Film 1 8W 1 50PPM R 603 4 00141 407 100 Resistor Metal Film 1 8W 1 50PPM R 604 4 00141 407 100 Resistor Metal Film 1 8W 1 50PPM R 605 4 00141 407 100 Resistor Metal Film 1 8W 1 50PPM R 606 4 00191 407 49 9 Resistor Metal Film 1 8W 1 50PPM R 607 4 00169 407 249 Resistor Metal Film 1 8W 1 50PPM R 608 4 00169 407 249 Resistor Metal Film 1 8W 1 50PPM R 609 4 00138 407 10 0K Resistor Metal Film 1 8W 1 50PPM R 610 4 00138 407 10 0K Resistor Metal Film 1 8W 1 50PPM R 611 4 00030 401 10 Resistor Carbon Film 1 4W 5 R 612 4 00158 407 2 00K Resistor Metal Film 1 8W 1 50PPM R 613 4 00158 407 2 00K Resistor Metal Film 1 8W 1 50PPM R 614 4 00185 407 4 02K Resistor Metal Film 1 8W 1 50PPM R 615 4 00193 407 499 Resistor Metal Film 1 8W 1 50PPM R 616 4 00193 407 499 Resistor Metal Film 1 8W 1 50PPM R 617 4 00193 407 499 Resistor Metal Film 1 8W 1 50PPM R 618 4 00193 407 499 Resistor Metal Film 1 8W 1 50PPM R 619 4 00193 407 499 Resistor Metal Film 1 8W 1 50PPM R 620 4 00193 407 499 Resistor Metal Film 1 8W 1 50PPM R 621 4 00030 401 10 Resistor Carbon Film 1 4W 5 R 622 4 00191 407 49 9 Resistor Metal Film 1 8W 1
80. AT FOR MORE INFO AWC data is saved as ASCII text Each line of the file consists of a single numerical value followed by a carriage return linefeed The first line is the number of data points in the waveform The second line is the sampling frequency in Hz The third line is the trigger source and the fourth line the internal trigger rate The remainder of the lines are the waveform amplitude points There is one line for each point There must be a minimum of 8 points and a maximum of 16 300 points for each waveform The value of the data is the waveform amplitude in volts at that data point Sample files with extension txt are included with the AWC program distribution Be sure to read the readme txt file included in the AWC zip file for any changes in the software Some examples of waveform files e g sample1 txt are also included for reference 7 7 ES Arbitrary Waveform Composer iis 7 8 DS345 Circuit Description BOTTOM PC BOARD POWER SUPPLIES SHEET 1 OF 7 All of the DS345 circuitry is referenced to an internal ground that is floating from the chassis ground The interface board see sheet 5 contains the only circuitry that is earth ground referenced The 15 volt unswitched power supplies are regulated by 3 terminal regu lators U100 and U101 The remaining supplies are referenced to a precision 5 volt reference U108 When shut down the regulators are still active but regulating to near zero volts The follow
81. ATION Introduction The DS345 has built in test and calibration routines that allow the user to quickly and easily test and calibrate virtually the entire instrument SHIFT CALIBRATE cycles the DS345 through the calibration menu Self test and autocal are started by pressing any UNITS keys while the menu line is dis played SELF TEST The DS345 s always executes a self test on power up self tests can also be initiated from the test menu These tests check most of the analog and digital signal generation circuitry in the DS345 Pressing any UNITS key when the SELF TEST menu item is displayed starts the self tests The tests take about three seconds to execute and should end with the display test pass If the self test encounters a problem it will immediately stop and display a warning message See the TROUBLESHOOTING section for a list and explanation of the error messages If the DS345 fails any test it still may be operated sim ply press any key to erase the error message note the error Gain FS Err can occur if a signal is applied to the external AM input during self test Disconnect any signals at this input during self test The DS345 tests its CPU and data memory ROM program memory calibra tion constant integrity ASIC waveform memory modulation program memo ry 12 bit waveform DAC analog to digital converter output amplifier offset and amplitude control circuits frequency doubler and square wave compara tor It
82. Allow the thermal converter output to settle about 10 15 seconds and record the voltage as Vref the voltage should be about 7 mV At 96 frequencies between 313500 Hz and 30 001 000 Hz in 312500 Hz steps repeat the following procedure 4 Set the DS345 s output frequency and allow the converter to settle The new calbyte for this frequency is given by 0 556 V f new calbyteold sayoz dc The calbyte should be in the range 8000 to 23000 The calbyte number for a given frequency is number 20 f 1000Hz 312500 Hz that is 313500 Hz 21 626000 Hz 22 etc 5 Set calbyte 117 to the same value as calbyte 116 Square Wave Amplitude This calibration corrects the DS345 s square wave amplitude response This calibration depends on frequency and is calibrated at 98 frequency points in the DS345 s frequency range The square wave symmetry calibration should be done after this calibration 1 Set the DS345 to square wave 1 kHz 10 Vpp Connect the DS345 s out put to the oscilloscope with a 50Q terminator Set the DS345 s frequency step size to 312500 Hz Set the oscilloscope to 2 V div vertical and 1 ms div horizontal 2 Set calbyte 118 to 16384 3 Measure the peak to peak amplitude of the square wave and record as Vref At 96 frequencies between 313500 Hz and 30 001 000 Hz in 312500 Hz steps repeat the following procedure 4 Set the DS345 s output frequency and measure the peak to peak ampli tude Th
83. C 567 C 572 C 573 5 00002 501 5 00074 515 5 00064 513 5 00263 513 5 00074 515 5 00100 517 5 00100 517 5 00100 517 5 00100 517 5 00100 517 5 00262 548 5 00262 548 5 00262 548 5 00262 548 5 00262 548 5 00262 548 5 00262 548 5 00262 548 5 00262 548 5 00262 548 5 00262 548 5 00262 548 5 00262 548 5 00262 548 5 00262 548 5 00262 548 5 00262 548 5 00262 548 5 00262 548 5 00262 548 5 00262 548 5 00262 548 5 00262 548 5 00262 548 5 00262 548 5 00262 548 5 00262 548 5 00262 548 5 00262 548 5 00100 517 5 00262 548 5 00262 548 5 00262 548 5 00262 548 5 00262 548 5 00262 548 5 00262 548 5 00262 548 5 00100 517 5 00100 517 100P 015U 0047U 0012U 015U 2 2U 2 2U 2 2U 2 2U 2 2U 01U AXIAL 01U AXIAL 01U AXIAL 01U AXIAL 01U AXIAL 01U AXIAL 01U AXIAL 01U AXIAL 01U AXIAL 01U AXIAL 01U AXIAL 01U AXIAL 01U AXIAL 01U AXIAL 01U AXIAL 01U AXIAL 01U AXIAL 01U AXIAL 01U AXIAL 01U AXIAL 01U AXIAL 01U AXIAL 01U AXIAL 01U AXIAL 01U AXIAL 01U AXIAL 01U AXIAL 01U AXIAL 01U AXIAL 2 2U 01U AXIAL 01U AXIAL 01U AXIAL 01U AXIAL 01U AXIAL 01U AXIAL 01U AXIAL 01U AXIAL 2 2U 2 2U Capacitor Ceramic Disc 50V 10 SL Capacitor Mylar Poly 50V 10 Rad Capacitor Mylar Poly 50V 5 Rad Capacitor Mylar Poly 50V 5 Rad Capacitor Mylar Poly 50V 10 Rad Capacitor Tantalum 35V 20 Rad Capacitor Tantalum 35V 20 Rad Capacitor Tantalum 35V
84. Disc 50V 10 SL LED Rectangular LED Rectangular LED Rectangular LED Rectangular 9 2 ees Component Part List D5 D6 D7 D8 D9 D 10 D11 D 12 D 13 D 14 D 16 D17 D 18 D 19 D 20 D 21 D 22 D 23 D 24 D25 D 26 D 27 D 28 D 29 D 30 D 31 D 32 D 33 D 34 D 35 D 36 D 37 D 39 D 40 D 41 D 42 D 43 D 44 D 45 D 48 D 49 D 50 D 51 D 52 D 53 D 54 D 100 D 101 D 102 D 103 3 00012 306 3 00012 306 3 00377 305 3 00455 310 3 00012 306 3 00012 306 3 00012 306 3 00012 306 3 00012 306 3 00012 306 3 00455 310 3 00012 306 3 00012 306 3 00012 306 3 00012 306 3 00012 306 3 00012 306 3 00885 306 3 00455 310 3 00455 310 3 00455 310 3 00455 310 3 00455 310 3 00455 310 3 00885 306 3 00455 310 3 00547 310 3 00455 310 3 00455 310 3 00455 310 3 00455 310 3 00455 310 3 00455 310 3 00455 310 3 00455 310 3 00455 310 3 00455 310 3 00455 310 3 00455 310 3 00547 310 3 00004 301 3 00004 301 3 00004 301 3 00004 301 3 00004 301 3 00004 301 3 00226 301 3 00226 301 3 00226 301 3 00226 301 GREEN GREEN GL9ED2 GREEN COATED GREEN GREEN GREEN GREEN GREEN GREEN GREEN COATED GREEN GREEN GREEN GREEN GREEN GREEN YELLOW GREEN COATED GREEN COATED GREEN COATED GREEN COATED GREEN COATED GREEN COATED YELLOW GREEN COATED RED COATED GREEN COATED GREEN COATED GREEN COATED GREEN COATED GREEN COATED GREEN COATED GREEN COATED GREEN COATED GREEN COATED GREEN COATED GREEN
85. EFT ARROW Then press twice Display shows point number 4 last point UNITS twice made Points 2 3 and 4 now have y value 800 Decrement point number to point 3 Activate y 11 Press MODIFY DOWN ARROWJ SHIFT value and set to 1200 Oops Point 4 is extra RIGHT ARROW and 1 2 O O UNITS Activate point number and increment to point 4 12 Press SHIFT LEFT ARROW MODIFY UP ARROW 13 Press CLR 14 DONE Delete point 4 y value becomes no data We only entered 4 data points The DS345 will automatically fill in the 4 trailing zero values when it loads the waveform RAM The DS345 only adds enough zeroes to make the total number of points equal to 8 and none if there are 8 or more points 2 31 BE Arbitrary Waveform Editing VECTOR EDITING Described below are the methods for editing vector format arbitrary wave forms Each stored data value vertex contains an x value address in wave form RAM and y value amplitude The vertices in the data list are connect ed by straight lines when the DS345 loads the waveform RAM For a given vertex the display is switched between x and y values by pressing STEP SIZE Vertex Number The vertex number can be set to any value between 0 and the number of ver tices in the current waveform The absolute maximum vertex number is 6143 there can only be 6144 vertices in a waveform The vertex number may be set using either the keypad or the MODIFY up down
86. FT ARROW then UNITS 19 Press SHIFT RIGHT ARROW STEP SIZE and 8 O O UNITS 20 DONE 2 34 Select vertex and increment to 3 then select y value and set to 2000 Select x value and set to 225 Select vertex and increment to 4 then select x value and set to 275 Select y value and set to 50 Select vertex and increment to 5 then select y value and set to 225 Select x value and set to 425 Select vertex and increment to 6 then select x value and set to 500 The y value is automatically set to 0 Select vertex number and duplicate vertex Vertex 7 created with value 500 0 Select the x value of vertex 7 and set to 800 The scope should now show a heartbeat wave form PROGRAMMING THE DS345 GPIB Communications RS232 Communications Front Panel LEDs Data Window Command Syntax The DS345 Function Generator may be remotely programmed via the RS232 or GPIB IEEE 488 interfaces Any computer supporting one of these inter faces may be used to program the DS345 Only one interface is active at a time The active interface may be set by entering either the GPIB or RS232 menu and turning the interface ON The interfaces are exclusive so while one is on the other will always be off not responsive All front and rear panel features except power may be controlled The DS345 supports the IEEE 488 1 1978 interface standard It also sup ports the required common commands of the IEEE 48
87. L TESTS These simple tests verify that the DS345 s circuitry is functional They are not intended to verify the DS345 s specifications Front Panel Test This test verifies the functionality of the front panel digits LED s and buttons 1 Turn on the DS345 while holding down FREQ A single segment of the leftmost digit should light 2 Use MODIFY DOWN ARROW to light each segment 7 of them and the decimal point of the leftmost two digits Only a single segment should be on ata time MODIFY UP ARROW will step backward through the pattern 3 Push the down arrow key again and all of the segments of all 12 digits should light 4 Press the down arrow key repeatedly to light each front panel indicator LED in turn top to bottom left to right At any time only a single LED should be on 5 After all of the LEDs have been lit further pressing of the front panel keys will display the key code associated with each key Each key should have a different keycode Internal Self Tests The internal self tests test the functionality of the DS345 circuitry 1 Turn on the DS345 The ROM firmware version number and the serial number should be displayed for about 3 seconds The self tests will execute and the message TEST PASS should be displayed If an error message appears see the TROUBLESHOOTING section for a description of the er rors Sine Wave This procedure visually checks the sine wave output for the correct frequency and any vis
88. MODEL DS345 synthesized Function Generator S RS Stanford Research Systems 1290 D Reamwood Avenue Sunnyvale California 94089 Phone 408 744 9040 e Fax 408 744 9049 email info thinkKSRS com www thinkSRS com Copyright 1993 99 2009 2012 2015 2016 by SRS Inc All Rights Reserved Revision 2 3 12 2016 Eee S345 Synthesized Function Generator Table of Contents Condensed Information SRS Symbols Safety and Use Specifications Abridged Command List Getting Started Introduction CW Function Generation Frequency Sweep Tone Bursts Operation Introduction to DDS DS345 Features Front Panel Features Rear Panel Features Function Setting Setting the Function Frequency Amplitude DC Offset Phase Sweeps and Modulation Modulation Parameters Modulation On Off Modulation Type Modulation Rate Amplitude Modulation External AM Internal AM Frequency Modulation Phase Modulation Burst Modulation Burst Count Starting Point Frequency Sweeps Sweep Type Sweep Frequencies Sweep Markers Sweep Outputs Trigger Generator Arbitrary Modulation Patterns Pulse Generation Instrument Setup Default Settings Store and Recall 2 7 2 12 2 18 2 19 2 19 2 19 2 20 2 21 2 22 2 23 2 24 2 25 2 25 2 25 GPIB and RS232 Setup Self Test and Autocal Arbitrary Waveform Editing Edit Menu Point Format Editing Point Format Example Vector Format Editing Vector Format Example Programming Programming the DS
89. Mini Electrolytic 50V 20 Radial Capacitor Ceramic 50V 80 20 Z5U AX Capacitor Ceramic 50V 80 20 Z5U AX Capacitor Ceramic 50V 80 20 Z5U AX Capacitor Ceramic 50V 80 20 Z5U AX Capacitor Ceramic 50V 80 20 Z5U AX Capacitor Ceramic 50V 80 20 Z5U AX Capacitor Mylar Poly 50V 5 Rad Cap Monolythic Ceramic 50V 20 Z5U Capacitor Electrolytic 50V 20 Rad Cap Mini Electrolytic 50V 20 Radial Capacitor Ceramic Disc 50V 20 Z5U Capacitor Tantalum 35V 20 Rad Capacitor Ceramic Disc 50V 20 Z5U Capacitor Tantalum 35V 20 Rad Capacitor Ceramic Disc 50V 10 SL Capacitor Ceramic Disc 50V 10 SL Capacitor Ceramic Disc 50V 10 SL Cap Monolythic Ceramic 50V 20 Z5U Cap Monolythic Ceramic 50V 20 Z5U Capacitor Ceramic Disc 50V 10 SL Cap Monolythic Ceramic 50V 20 Z5U Capacitor Tantalum 35V 20 Rad Cap Monolythic Ceramic 50V 20 Z5U Cap Monolythic Ceramic 50V 20 Z5U Cap Monolythic Ceramic 50V 20 Z5U Capacitor Variable Misc Cap Monolythic Ceramic 50V 20 Z5U Cap Mini Electrolytic 25V 20 Radial Capacitor Tantalum 35V 20 Rad Cap Monolythic Ceramic 50V 20 Z5U Cap Mini Electrolytic 25V 20 Radial Capacitor Tantalum 35V 20 Rad Capacitor Tantalum 35V 20 Rad Capacitor Mylar Poly 50V 10 Rad Capacitor Mylar Poly 50V 10 Rad Cap Monolythic Ceramic 50V 20 Z5U Capacitor Tantalum 35V 20 Rad Capacitor Ceramic
90. P and SINGLE Sweep 10V Sweep Output ov Blank Lift Output TRIANGLE Sweep 2 21 EE Modulation and Sweeps i TRIGGER GENERATOR Introduction The DS345 has an internal trigger generator that triggers BURSTS and SIN GLE sweeps from a wide variety of sources Once a BURST SWEEP is trig gered the DS345 will ignore all triggers until the BURST SWEEP is complete Therefore a BURST SWEEP cannot be affected by accidentally triggering too rapidly Trigger Source Press SHIFT TRIG SOURCE to display the trigger source Use the MODI FY keys to change the source The choices are Source Function SINGLE The front panel TRIG key starts the BURST SWEEP RATE The internal rate generator starts the BURST SWEEP POS IN The rising edge of the TRIGGER input starts the BURST SWEEP NEG IN The falling edge of the TRIGGER input starts the BURST SWEEP LINE The power line frequency starts the BURST SWEEP Trigger Rate The frequency of the internal trigger rate generator is set by pressing SHIFT TRIG RATE The rate may be set to any value in the range 0 001 Hz to 10 kHz with two digits of resolution TRIG D LED The TRIG D LED indicates the DS345 s trigger status Each time a trigger is accepted the TRIG D LED flashes green If the DS345 is triggered again be fore the previous BURST SWEEP is complete the TRIG D LED will flash red indicating a trigger error At higher trigger rates a combination of triggers green and trigger errors r
91. ROW O UNITS STEP SIZE and 1 5 O UNITS 9 Press SHIFT LEFT ARROW MODIFY UP ARROWJ SHIFT RIGHT ARROW 1 7 5 UNITS 10 Press STEP SIZE then 3 O O UNITS 60 200 2 33 225 2000 425 225 500 0 800 0 175 300 Heartbeat Arbitrary Waveform Set output function to ARB Set vector entry mode if necessary Clear arb function The message arb cleared will be displayed Display edit line It should read 00000 i Vertex number 0 the first vertex has no data Activate x value and set to 50 We will let the DS345 add the 0 0 vertex automatically Switch to y value and set to 200 Select vertex number and increment to vertex 1 Select y value and set to 0 then select x value and set to 150 Select vertex and increment to 2 then select x value and set to 175 Select y value and set to 300 BE Arbitrary Waveform Editing 11 Press SHIFT LEFT ARROW MODIFY UP ARROWJ SHIFT RIGHT ARROW 2 0 0 0 UNITS 12 Press STEP SIZE then 2 2 5 UNITS 13 Press SHIFT LEFT ARROW MODIFY UP ARROW SHIFT RIGHT ARROW 2 7 5 UNITS 14 Press STEP SIZE then 5 O UNITS 15 Press SHIFT LEFT ARROW MODIFY UP ARROW SHIFT RIGHT ARROW 2 2 5 UNITS 16 Press STEP SIZE then 4 2 5 UNITS 17 Press SHIFT LEFT ARROW MODIFY UP ARROWJ SHIFT RIGHT ARROW 5 0 0 UNITS 18 Press SHIFT LE
92. SYNC OUTPUT and in the case of square waves to the amplitude control multiplier input Generating square waves by discrimi nating the sine wave signal produces a square wave output with rise and fall times much faster than allowed by either of the signal filters BE introduction ee 2 4 Front Panel Features REM SRQ ACT ERR TIMEBASE EXT ERR OUTPUTS SYNC FUNCTION 40V max S TANFORD RESEARCH SYSTEMS MODEL DS34 m7 30MHz SYNTHESIZED FUNCTION GENERATOR TATU TTL FUNCTION FREQ AMPL OFFS PHASE TRIG STEP SPAN RATE MRK STRTf STOP fMODULATION an non AAA m m Sele yes JIU uuu UUW UU ees LINSWP SINGLE MOD SWP LOG SWP AM INT FM om BURST RATE b ri 8 9 ARBEDIT DEFAULTS CALIBRATE sro rot SWEEP ON OFF BRST CNT SRQ RS232 DATA SWP CF R MRKSTOP MRKCF MRK SPAN LOCAL SPAN STEP A DEPTH 5 8 SIZE STOP f Ri MRK SPAN SPAN MRK m ON STBY AL V START 3 FREQ ee ji Le 1 Power Switch 2 MODIFY Keys 3 ENTRY Keys 4 Units Keys The power switch turns the DS345 on and off In the STBY position power is maintained to the DS345 s internal oscillator minimizing warmup time The modify keys permit the operator to increase or decrease the displayed parameter value The step size may be determined by pressing the STEP SIZE key the STEP LED will light Every displayed parameter has an asso ciated step size pres
93. Set the scope to 2 V div vertical and 200 ns div horizontal 2 Starting with C645 adjust C645 C644 C643 and C642 to make the out put rise time as fast as possible while minimizing the peak to peak ripple Several iterations of the capacitors may be needed to acheive optimum re sponse 3 Run autocal es Calibration im Harmonic Distortion Adjust This adjustment minimizes the DS345 s 2nd 3rd and 5th harmonic distor tion A complete calibration is necessary after this adjustment 1 Set the DS345 to sine wave 8 Vpp 15 kHz Connect the DS345 s output to the FFT analyzer with a 50Q terminator Set the FFT analyzer to display from DC to 100 kHz 2 Adjust P602 bottom board to minimize the levels of the third harmonic at 45 kHz and the 5th harmonic at 75 kHz 3 Readjust the AC DCgain balance of the output amplifier see Output Am plifier Bandwidth adjustment step 2 4 Recalibrate the DS345 M Calibration ee CALIBRATION The following procedures determine the values of the DS345 s calbytes Any adjustments should be done before starting calibration Allow the DS345 at least 1 2 hour warmup before beginning calibration The first calibration the 5 00 V reference calibration requires the DS345 s top cover be removed All other calibrations should be done with the DS345 completely assembled and 1 2 hour of warmup after reassembly When the new calbyte values are de termined they should be entered into the DS345 s RAM In ca
94. Status Byte bit oO k name unused unused Query Error unused usage Set on output queue overflow 3 12 EE Programming Commands Il 4 Execution err Set by an out of range parameter or non completion of some command due a condition such as an incorrect wave form type 5 Command err Set by a command syntax error or unrecognized command 6 URQ Set by any key press 7 PON Set by power on This status byte is defined by IEEE 488 2 1987 and is used primarily to report errors in commands received over the communications interfaces The bits in this register stay set once set and are cleared by reading them or by the CLS command DDS Status Byte bit name usage 0 Trig d Set when a burst or sweep is triggered 1 Trig Error Set when a trigger rate error occurs 2 Ext Clock Set when the DS345 is using an external clock source 3 Clk Error Set when a external clock error occurs 4 Warmup Set after the warmup period has expired 5 Test Error Set if a self test error occurs 6 Cal Error Set if a self cal error occurs 7 mem err the stored setting were corrupt on power up The Ext Clk bit will be set whenever the DS345 is locked to an external clock source The Warmup bit will be set and remain set after the warmup period has expired The rest of the bits in this register are set when the corresponding event occurs and remain set until cleared by reading this status byte or by the CLS command EM Programming Co
95. TWARE Introduction Installing AWC Getting Started With AWC The Arbitrary Waveform Composer AWC is a program that allows the user to create or import arbitrary waveforms and then download the waveform to the DS345 AWC has the ability to create arbitrary waveforms store waveforms to disk edit stored waveforms and download waveforms to the DS345 AWC can edit and download waveforms that it has created or waveforms created from other sources and then stored as an ASCII text file AWC is designed to run on Windows systems running XP 2000 Me 98 Monitor resolution should be set at 800x600 or higher AWC communicates with the DS345 though the RS232 interface or a National Instruments hardware implementation of the GPIB interface Install AWC ZIP file which you can download from the SRS website www thinksrs com Use unzip software to extract the contents of the ZIP archive Install as follows 1 The AWC software requires National Instruments NI VISA version 2 6 or higher installed on your computer If you have version 2 6 or higher skip to step 3 below 2 Inside the unzipped temporary directory navigate to the VISA Run Time Engine 2 6 folder Inside this folder run Nivisa26Oruntime exe and follow the on screen instructions 3 If you have LabView version 6 1 installed on your computer skip step 4 below Just run Arbitrary Waveform Composer exe If you have any other version of LabView installed on your computer or do not
96. The 0 to 5V range is used for normal AM opera tion while the 5V range is used for DSBSC modulation This input is always active and should only be be connected if AM is desired The shield of this in put is tied to the shield of the function output and may be floated up to 40V relative to earth ground 2 7 BM Cua Timebase Input This 1kQ impedance input allows the DS345 to lock to an external timebase The external source should be greater than 1V pk to pk and should be within 2 ppm of 10 MHz or any subharmonic down to 1 25 MHz The shield of this input is connected to earth ground 3 Auxiliary Outputs 10 MHz Output This output produces a gt 1V pk pk 10 MHz sinewave from the DS345 s inter nal oscillator It expects a 50Q termination The shield of this output is connected to earth ground Modulation Out This output generates a 0 5V representation of the current modulation func tion The shield of this output is tied to that of the function output and may be floated up to 40V relative to earth ground Trigger Output This TTL compatible output goes high when a triggered sweep or burst be gins and goes low when it ends This may be used to synchronize an exter nal device to the sweep burst The shield of this output is tied to that of the function output and may be floated up to 40V relative to earth ground Sweep Output This output generates a O 10 V ramp that is synchronous with the DS345 s frequency sweep The shield of
97. You can even do bursts of groups of pulses each pulse has to be the same width and separated by 1 pulse width Procedure Start with a square wave as the main waveform selecting the square wave frequency 1 MHz max for this purpose so that half of a period is the width of the pulse you want Then choose burst modulation with a burst count of 1 and turn on sweep mode Use the phase control to adjust the phase of the square wave within the burst so that only a positive going or negative going half cycle is visible generally a phase shift of 180 degrees for a positive pulse Note that by varying the phase you can also delay a pulse by up to one half a period of the frequency with respect to an external trigger Finally use the offset control to adjust the baseline of the pulse to be 0 Volts You will have to start with a square wave amplitude of at most one half of the maxi mum DS345 peak to peak amplitude This gives a maximum pulse amplitude of 10 Volts into high impedance or 5 Volts into 50 Ohms After setting this up changing the burst rate will change the pulse repetition rate and changing the square wave frequency will change the pulse width To do groups of pulses simply increase the burst count to the number of pulses you want in the burst Use the trigger input connector and set the trig ger control to external positive or negative for externally triggered bursts If the source of the trigger has a 10 MHz clock input connecting th
98. abled If all of the trigger choices are deselected the DS345 s modulation will be turned off continuous waveforms The default setting is continuous waveforms The six trigger choices are the five that are internal to the DS345 plus the PC mouse If PC mouse is selected a trigger button will appear on the AWC screen The DS345 will trigger each time the button is clicked The zoom menu allows the AWC display to zoom in and out on features of the arbitrary waveform This is useful when the waveform has a many points This menu is disabled when there is no waveform on screen This selection sets the AWC display to any portion of the current waveform There are two parameters the starting and ending point numbers to be displayed Magnifies the center 50 of the waveform by a factor of two Zooms out from the center of the screen by a factor of two Pans to the right by 50 of the screen width Pans to the left by 50 of the screen width Zooms out to display the entire waveform The selections in this menu provide some useful information about AWC Selecting this menu item brings up a window with general information about the AWC program and about each of the menu items as well as some troubleshooting tips Displays the current version of AWC and general information about SRS Provides information about the numerical coding of the trigger source line of the data file format 7 6 Men Arbitrary Waveform Composer Hi DATA FILE FORM
99. ade the associated calibrations must be made All adjustments must be complete before calibration is start ed First remove the DS345 s top cover by removing the four retaining screws On units with an optional oscillator remove the mounting screw half way back on the left side of the chassis Next remove the two left hand screws securing the top circuit board This board will hinge open the option al oscillator hinges with the circuit board Set the cal enable switch SW300 switch 2 to ON NOTE The chassis ground and circuit ground float relative to each other For voltage measurements use the FUNCTION output BNC shield as a ground reference Clock Adjustment This adjustment sets the DS345 s internal 40 MHz oscillator Instructions for both standard and optional oscillators are given below The oscillator calibra tion should be done after this adjustment 1 Connect the DS345 s 10 MHz output to the frequency counter input The counter should use the frequency standard for its timebase Be sure that the 6 3 M Calibration ee DS345 has had at least 1 2 hour to warm up 2 Set calbyte number O to 2980 For a unit with an optional oscillator set SW300 switch 1 bottom board to OFF 3 Adjust L203 top board so that the output U205 pin 6 is closest to 0 V DC Adjust L204 top board so that the oscillator frequency is within 1 Hz of 10 0 MHz if the unit has an optional oscillator 4 Set SW300 switch 1 to ON Set calbyte 0 t
100. age Q606 3 00028 325 2N5771 Transistor TO 92 Package Q607 3 00027 325 2N5770 Transistor TO 92 Package Q608 3 00022 325 2N3906 Transistor TO 92 Package Q609 3 00021 325 2N3904 Transistor TO 92 Package Q610 3 00022 325 2N3906 Transistor TO 92 Package Q611 3 00021 325 2N3904 Transistor TO 92 Package Q612 3 00028 325 2N5771 Transistor TO 92 Package Q613 3 00027 325 2N5770 Transistor TO 92 Package Q614 3 00017 324 MM4049 Transistor TO 72 Package Q615 3 00027 325 2N5770 Transistor TO 92 Package Q616 3 00027 325 2N5770 Transistor TO 92 Package Q617 3 00028 325 2N5771 Transistor TO 92 Package Q618 3 00021 325 2N3904 Transistor TO 92 Package Q619 3 00022 325 2N3906 Transistor TO 92 Package Q700 3 00022 325 2N3906 Transistor TO 92 Package Q701 3 00022 325 2N3906 Transistor TO 92 Package Q702 3 00022 325 2N3906 Transistor TO 92 Package R100 4 00081 401 470 Resistor Carbon Film 1 4W 5 R 101 4 00138 407 10 0K Resistor Metal Film 1 8W 1 50PPM R102 4 00188 407 4 99K Resistor Metal Film 1 8W 1 50PPM R103 4 00057 401 220 Resistor Carbon Film 1 4W 5 R104 4 00057 401 220 Resistor Carbon Film 1 4W 5 R105 4 00179 407 30 1K Resistor Metal Film 1 8W 1 50PPM R106 4 00138 407 10 0K Resistor Metal Film 1 8W 1 50PPM R107 4 00034 401 10K Resistor Carbon Film 1 4W 5 R108 4 00024 401 1 2K Resistor Carbon Film 1 4W 5 R109 4 00024 401 1 2K Resistor Carbon Film 1 4W 5 R110 4 00022 401 1 0M Resisto
101. ant byte first There should be i data points sent 4 Send the checksum the sum of i data points least significant byte first Arbitrary AM Each arbitrary AM point is a 16bit integer value This value is the fraction of front panel amplitude to be output The values range from 32767 1 0 full amplitude to 32767 1 0 amplitude The value for a desired modulation fraction is easily calculated from the formula value 32767 fraction For normal AM the values should range from 0 to 32767 1 0 while for DSBSC the 32767 1 0 to 32767 1 0 range is used The i data values should be followed by a 16 bit checksum simply the 16 bit sum of the data values Thus a total of i 1 16 bit values will be sent When modulation is enabled each modulation point takes N 0 3us to execute where N is the arbitrary modulation rate divider see the AMRT command The MODULATION OUTPUT will output the modulation waveform when modulation is enabled 5 0 V corresponds to 100 output and 5 0V corresponds to 100 modu lation Arbitrary FM Each arbitrary FM point is a 32 bit integer value This value is the frequency to be output If the frequency is not allowed for the currently selected wave form an error will be generated The 32 bit value is calculated from the for mula value 232 frequency 40 MHz Thus the j data points form a list of j frequencies to be output The i data values should be followed by a 32 bit checksum simply the 32 bit
102. at the phase shift ranges from span 2 to span 2 The PDEV query returns the current phase shift RATE x The RATE command sets the modulation rate to x Hertz x is rounded to 2 significant digits and may range from 0 001 Hz to 10 kHz The RATE query returns the current modulation rate SPAN x The SPAN command sets the sweep span to x Hertz An error will be gener ated if the sweep frequency is less than or equal to zero or greater than al lowed by the current function The sweep will be from center freq span 2 to 3 5 EM Programming Commands center freq span 2 A negative span will generate a downward sweep from maximum to minimum frequency The SPAN query returns the current sweep span SPCF x The SPCF command sets the sweep center frequency to x Hertz An error will be generated if the sweep frequency is less than or equal to zero or greater than allowed by the current function The SPCF query returns the current sweep center frequency SPFR x The SPFR command sets the sweep stop frequency to x Hertz An error will be generated if the sweep frequency is less than or equal to zero or greater than allowed by the current function The SPFR query returns the current sweep stop frequency If the stop frequency is less than the start frequency the STFR command a downward sweep from maximum to minimum fre quency will be generated SPMK The SPMK command sets the sweep span to the sweep marker frequency That is
103. bit If i 1 the power on status clear bit is set and all status registers and enable registers are cleared on power up If i 0 the bit is cleared and the status enable registers maintain their values at power down This allows the pro duction of a service request at power up SRE i The SRE common command sets the serial poll enable register to the deci mal value of the parameter i STB i The STB common query reads the value of the serial poll byte If the pa rameter i is present the value of bit i is returned O or 1 Reading this regis ter has no effect on its value as it is a summary of the other status registers DENA 7 i The DENA command sets the DDS status enable register to the decimal val ue i STAT i The STAT query reads the value of the DDS status byte If the parameter i is present the value of bit i is returned Reading this register will clear it while reading bit i will clear just bit i EM Programming Commands Hardware Test and Calibration Commands NOTE These commands are primarily intended for factory calibration use and should never be needed dur ing normal operation Incorrect use of some of these commands can destroy the calibration of the DS345 CAL The CAL common query initiates the DS345 s self calibration routines When the calibration is complete the status of the calibration is returned The status may have the following values see TROUBLESHOOTING sec fitat isrvabre detail
104. carrier null the attenuator ratios and the clock frequency These values are stable and should not need adjust ment except during an annual recalibration note Disconnect any signals from the External AM input during Autocal 2 27 BRR 0345 Setup The items not calibrated are the frequency dependent amplitude corrections the doubler carrier null the attenuator ratios and the clock frequency These values are stable and should not need adjustment except during the yearly recalibration 2 28 ARBITRARY WAVEFORM EDITING Introduction Sampling Rate SYNC Output EDIT MENU Storage Format Clearing Current Waveform EDITING This section describes the DS345 s arbitrary waveform capabilities and how to edit those waveforms from the front panel The DS345 can store arbitrary waveforms in two formats point and vector In point format the DS345 stores only a list of amplitude values to load into the waveform RAM This list can be up to 16 300 points long with each memory point representing a point in the output waveform In vector format the data stored is a list of vertices x y pairs of values up to 6144 pairs Each data pair specifies an address in waveform RAM the x value and the amplitude at that point the y value The waveform RAM locations between successive vertices are automatically filled in by connecting the vertices with straight lines Note Front panel editing can be very tedious Large or complex waveform
105. citor Ceramic Disc 50V 10 SL C 654 5 00008 501 22P Capacitor Ceramic Disc 50V 10 SL C 655 5 00008 501 22P Capacitor Ceramic Disc 50V 10 SL C 656 5 00023 529 1U Cap Monolythic Ceramic 50V 20 Z5U C700 5 00023 529 1U Cap Monolythic Ceramic 50V 20 Z5U C 701 5 00023 529 1U Cap Monolythic Ceramic 50V 20 Z5U C702 5 00023 529 1U Cap Monolythic Ceramic 50V 20 Z5U C703 5 00023 529 1U Cap Monolythic Ceramic 50V 20 Z5U C704 5 00023 529 1U Cap Monolythic Ceramic 50V 20 Z5U C705 5 00023 529 1U Cap Monolythic Ceramic 50V 20 Z5U C707 5 00219 529 01U Cap Monolythic Ceramic 50V 20 Z5U C708 5 00219 529 01U Cap Monolythic Ceramic 50V 20 Z5U C709 5 00219 529 01U Cap Monolythic Ceramic 50V 20 Z5U D100 3 00011 303 RED LED T1 Package D207 3 00203 301 1N5711 Diode D208 3 00004 301 1N4148 Diode D209 3 00203 301 1N5711 Diode D 210 3 00004 301 1N4148 Diode D 401 3 00004 301 1N4148 Diode D 402 3 00004 301 1N4148 Diode D600 3 00443 301 1N5238B Diode D700 3 00004 301 1N4148 Diode D 701 3 00004 301 1N4148 Diode J 100 1 00143 101 TEST JACK Vertical Test Jack J 101 1 00143 101 TEST JACK Vertical Test Jack J 102 1 00143 101 TEST JACK Vertical Test Jack J 103 1 00143 101 TEST JACK Vertical Test Jack J 205 1 00143 101 TEST JACK Vertical Test Jack J 213 1 00143 101 TEST JACK Vertical Test Jack J 215 1 00143 101 TEST JACK Vertical Test Jack J 216 1 00143 101 TEST JACK Vertical Test Jack J 217 1
106. clock from U517A latches the input data into U503 from the GPIB controller 8 2 ES 0245 Circuitry OUTPUT AMPLIFIER SHEET 6 of 7 The output amplifier takes the differential signal from the DDS top board and generates the single ended 20 volt P P signal that is fed to the output attenu ators The amplifier has a rise time of about 10 ns 85 MHz bandwidth to preserve pulse shapes and after series 50 ohm resistor R636 can deliver 10 volts into a 50 ohm load The output from the top board is a 4 mA current swing on an 8 mA bias This current across R615 and R616 develops voltage swings of 400 mV at the input of the amplifier at the bases of Q615 and Q616 2 x 4 mA 8 mA times 57 6 ohms equals 460 mV max or 400 mV nom The amplifier is symmetrical for the positive and negative halves of the cir cuit so the following description will follow the negative path only The cur rent through R629 determines the output voltage swing and this current is determined by the drive at the base of Q612 along with the current injected into the R620 R629 junction via the feedback path through R630 R639 and R620 The open loop gain of the output is very high due to the Q604 stage as its emitter load is 100 ohms and its effective collector load is very high the collector of Q605 Q609 and Q600 are just emitter followers which sup ply the final output drive current The closed loop gain of the amp is fixed at 25 by the feedback effective fe
107. ctrum analyzer to 1 MHz center frequency 20 kHz span 3 The 1 MHz fundamental output and the two modulation sidebands1 kHz away should be visible Verify than any harmonics of the sidebands at 2kHZ 3 kHz offset are less than 35 dB down Record the results THIS COMPLETES THE PERFORMANCE TESTS E Performance Tests Ml DS345 PERFORMANCE TEST RECORD Serial Number Date Tested By Comments Functional Tests Front Panel Test Self Tests Sine Wave Square Wave Amplitude Flatness Output Level Minimum Actual Maximum Performance Tests Frequency Accuracy 9 999 950 Hz 10 000 050 Hz Amplitude Accuracy sine 100 Hz 3 54 Vrms sine 1 kHz 3 54 Vrms sine 10 kHz 3 54 Vrms sine 100 kHz 3 54 Vrms sine 1 kHz 1 Vrms sine 1 kHz 0 5 Vrms sine 1 kHz 0 25 Vrms sine 1 kHz 125 mVrms sine 1 kHz 75 mVrms sine 1 kHz 40 mVrms sine 1 kHz 25 mVrms square 100 Hz 5 Vrms square 1 kHz 5 Vrms square 10 kHz 5 Vrms triangle 100 Hz 2 89 Vrms triangle 1 kHz 2 89 Vrms triangle 10 kHz 2 89 Vrms 3 459 Vrms 3 459 Vrms 3 459 Vrms 3 459 Vrms 0 966 Vrms 0 483 Vrms 0 242 Vrms 121 mVrms 72 5 mVrms 38 6 mVrms 24 15 mVrms 4 85 Vrms 4 85 Vrms 4 85 Vrms 2 80 Vrms 2 80 Vrms 2 80 Vrms sine 1 kHz 3 Vrms reference X Tolerance 4 2 of X sine 2 001 MHz 3 Vrms sine 4 001 MHz 3 Vrms sine 6 001 MHz 3 Vrms 0 958X 3 621 Vrms 3 621 Vrms 3 621 Vrms 3 621 Vrms 1 034 Vrms
108. cuit Thru hole Pkg U 303 3 00406 340 74HCT374 Integrated Circuit Thru hole Pkg U 304 3 00406 340 74HCT374 Integrated Circuit Thru hole Pkg 9 8 eee Component Part List i U 305 U 306 U 400 U 401 U 402 U 403 U 600 U 601 U 602 VR100 Zo Zo Zo Zo Zo Zo Zo Zo Zo Zo Zo Zo Zo Zo Zo Zo Zo Zo Zo Zo Zo Zo Zo Zo Zo Zo Zo Zo Zo Zo Zo Zo Zo Zo Zo Zo Zo Zo Zo Zo 3 00406 340 3 00406 340 3 00166 340 3 00316 340 3 00044 340 3 00044 340 3 00429 340 3 00141 329 3 00149 329 4 00355 435 0 00014 002 0 00017 002 0 00025 005 0 00043 011 0 00048 011 0 00081 032 0 00089 033 0 00096 041 0 00109 050 0 00150 026 0 00153 057 0 00163 007 0 00165 003 0 00187 021 0 00208 020 0 00209 021 0 00231 043 0 00233 000 0 00237 016 0 00238 026 0 00241 021 0 00243 003 0 00244 021 0 00249 021 0 00256 043 0 00259 021 0 00267 052 0 00268 052 0 00284 025 0 00299 000 0 00314 040 0 00386 003 0 00387 031 0 00407 032 0 00414 033 0 00435 000 0 00447 007 0 00524 048 0 00893 026 1 00066 112 74HCT374 74HCT374 74HC153 74HC151 74HC244 74HC244 LT1008 LM337T LM317T 56V 500A 6J4 TRANSCOVER 3 8 4 40 KEP 6 32 KEP 320882 4 4 SPLIT 1 1 2 18 4 40X1 4PF GROMMET2 TO 5 TO 18 4 40X1 4PP 4 40X3 8PF 4 40X3 8PP 1 32 4 SHOULD HANDLE1 F1404 6 32X1 4PF 4 40X3 16PP TO 220 6 32X1 1 8PP 6 32X1 1 2PP 6 SHOULDER 4 40X1 2 PP 6 1 2 22 RED 6 1 2 22 BL 10 32X1 2 1 8 ADHES TAPE 8
109. d DS345 n exit 1 number 1000 1000 points sum 0 initialize checksum now we will calculate 2 byte amplitude data each point is given by value 32767 full amplitude for i 0 i lt number i t 32767 0 sin 6 2831853 double i double number sine wave data i int t 0 5 convert to int sum data i add to checksum data number sum store checksum sprintf cmd MENAO MTYP2 MDWF5 n make sure modulation off until after loading set AM arb WF ibwrt ds345 cmd strlen cmd send commands sprintf cmd AMOD d n number arb modulation command ibwrt ds345 cmd strlen cmd ibrd ds345 cmd 40 read back reply before sending data ibwrt ds345 char data long 2 number 2 number of bytes 2 per data point 2 for checksum 3 16 ES Program Examples I sprintf cmd MENA1 n ibwrt ds345 cmd strlen cmd EXAMPLE 2 Arbitrary Frequency Modulation turn modulation on This program downloads an arbitrary FM pattern to the DS345 The modulating waveform is a sine wave The program calculates the FM pattern values sets the modulation type to FM modulation waveform to ARB downloads the pattern and enables modulation The program is written in C program to demonstrate arbitrary FM modulation Will generate a Sine wave FM of 50kHz carrier with 10 kHz span Written in M
110. de via JP501 The RS232 interface is handled by U512 which generates the required RS232 levels from the 5 volt interface supply The RS232 data in and out as well as DTR signals are optically coupled directly to the Z8800 processor UART during RS232 communication through U523 U520 and U522 respec tively During GPIB communications the parallel GPIB data is handled by shifting the data and control information in and out through shift registers U503 and U504 Along with the data clock through opto coupler U521 the circuit communicates through the Z8800 UART at 1x clock frequency or 1 25 MBaud U515B detects the serial start bit and forces an output queue start bit through U518A The SHIFT_CLK then begins after a one bit delay by U518B U506 generates eight clock cycles after which the RCO output of this counter resets the start bit detect flip flop disables the SHIFT_CLK and generates an output queue stop bit by presetting U518A The first incoming 8 data bits are shifted into U504 the command register af ter which they are cascaded into U503 the data register U503 transfers data to and from the GPIB controller U500 and U504 sets the appropriate bits to define the direction of data flow etc U517A and RC delay R501 C501 gen erate a delayed clock to clock data in the reverse direction parallel in into U503 along with mode bit SO from COMMAND STROBE In other words when COM_STB goes high setting SO on U503 high the delayed
111. dulation commands AMRT i AMOD i Sets the arbitrary modulation rate divider to i Allows downloading a i point arbitrary modulation waveform if the modulation type is AM FM or PM After execution of this query the DS345 will return the ASCII value 1 The binary waveform data may now be downloaded EE Abridged Command List M LDWF i j Allows downloading a j point arbitrary waveform of format i i 0 point format i 1 vector format After execution of this query the DS345 will return the ascii value 1 The binary waveform data may now be downloaded Setup Control Commands IDN RCL i RST SAV i Returns the device identification Recalls stored setting i Clears instrument to default settings Stores the current settings in storage location i Status Reporting Commands CLS ESE j ESR j PSC j SRE j STB j STAT j DENA j Clears all status registers Sets reads the standard status byte enable register Reads the standard status register or just bit j of register Sets the power on status clear bit This allows SRQ s on power up if desired Sets reads the serial poll enable register Reads the serial poll register or just bit n of register Reads the DDS status register or just bit n of register Sets reads the DDS status enable register Hardware Test and Calibration Control CAL TST Starts autocal and returns status when done Starts self test and returns s
112. dware Requirements Menus File Menu Edit Menu Waveform Menu Send Data Menu Set DS345 Menu Trigger Menu Zoom Menu Help Menu Data File Format 5 5 5 5 5 5 5 7 5 8 5 8 5 9 5 10 5 10 5 10 5 11 6 5 7 1 7 1 7 3 7 3 7 3 7 3 7 5 7 5 7 6 7 7 EE DS345 Synthesized Function Generator i For More Info 7 7 DS345 Circuitry Circuit Description 8 1 Bottom PC Board 8 1 Power Supplies 8 1 Microprocessor System 8 1 Display and Keyboard 8 1 Ribbon Cable Trigger and Sync 8 2 GPIB and RS232 Interfaces 8 2 Output Amplifier 8 3 Output Attenuator 8 3 Top PC Board 8 4 Ribbon Cable ADC DACs 8 4 Clocks 8 4 DDS ASIC and Memory 8 5 Amplitude and Sweep DACs 8 5 DDS Waveform DAC 8 6 DDS Output Filters and Doubler 8 6 Sync and Gain Adjust 8 6 Component Parts List 9 1 Bottom PC Board and Front Panel 9 1 Top PC Board 9 10 Optional PC Board 9 21 Miscellaneous Parts 9 22 Schematic Circuit Diagrams Sheet No Bottom PC Board Power Supplies 1 7 Microprocessor System 2 7 Display and Keyboard 3 7 Ribbon Cable Trigger and Sync 4 7 GPIB and RS232 Interfaces 5 7 Output Amplifier 6 7 Output Attenuator 7 7 Top PC Board Ribbon Cable ADC DACs 1 7 Clocks 2 7 DDS ASIC and Memory 3 7 Amplitude and Sweep DACs 4 7 DDS Waveform DAC 5 7 DDS Output Filters and Doubler 6 7 Sync and Gain Adjust 7 7 Front Panel Keypad 1 2 LED Display 2 2 Bottom PCB Component Placement Top PCB Component Placement Ee 0S345 Synthesized Function G
113. e ampli tude may be set with three digits of resolution If the DC offset is not zero the larger of the amplitude and the offset determines the resolution of both pa rameters The amplitude display is automatically adjusted such that all of the digits that may be changed are displayed Output Inversion For ramp and arbitrary functions the DS345 s output may be inverted This is useful for turning positive ramps into negative ramps or inverting arbitrary waveforms Pressing AMPL two times displays the invert enable option Use the UP DOWN MODIFY keys to enable or disable the inversion D C Only The output of the DS345 may be set to a DC level by entering an amplitude of OV When the amplitude is set to zero the A C waveform will be off and the DS345 may be used as a DC voltage source If the amplitude is zero the display will read no AC when the units are set to dBm TTL Settings Pressing SHIFT TTL sets the output amplitude and offset to TTL values 2 11 BEE Function Setting TTL levels are 5 Vpp with a 2 5V offset the output will swing between 0 and 5V ECL Settings Pressing SHIFT ECL sets the output amplitude and offset to ECL values ECL levels are 1 Vpp with a 1 3V offset the output will swing between 1 8V and 0 8V DC OFFSET The DC offset may range between 5V but is restricted such that Vac peakl Vgcl 25 V When OFFST is pressed a new value may be entered using any amplitude unit key the Vpp indicator
114. e errors occur repeatedly the unit may have an electrical problem The messages are listed alphabetically also listed is the status value returned by the TST command The DS345 s A D converter has an excessive DC offset gt 75mV This can mean a problem with the D A or A D circuits The DS345 s A D converter has the wrong gain A D measures the 5 00V ref erence voltage Can be a problem with the D A or the A D multiplexer The RAM calibration data has become corrupt The factory values will be re loaded from ROM This message is not a problem unless it occurs frequent ly which could indicate a problem with the battery backup circuits The DS345 s ROM has a checksum error XX is the checksum value The DS345 has detected a problem in its Z8800 Cpu The waveform DAC output offset control carrier null doesn t work should have 75mV to 225mV range at output BNC Error in linearity of ASIC controlled gain DAC U412A Checked at full 1 2 1 4 and 1 8 scale Error of ASIC controlled offset DAC U412B Checked at OV full scale Error in linearity of mimic DAC U401 Checked at full 1 2 1 4 and 1 8 Error in frequency doubler circuitry or Cauer filter Error in read write to waveform RAM x 1 U305 2 U306 3 U307 Can indicate problem with RAMs ASIC or bus interface circuits The waveform DAC U500 cannot generate full scale output The waveform DAC or amplitude control multiplier U500 and U702
115. e for sweeps is 0 001 Hz to 1 kHz 1000s to 0 001s sweep time The modulation rate may be set with two digits of resolution If the modulation waveform is set to ARB AM ARB FM ARB or PM ARB the modulation rate has a different meaning See the ARBITRARY MODULATION section for more details EE Modulation and Sweeps I AMPLITUDE MODULATION Introduction The DS345 has the ability to amplitude modulate its function output with both the internal modulation generator and an external analog voltage The inter nal modulation generator may modulate the output with a sine square pulse modulation triangle ramp or arbitrary modulation pattern The external modulation may be either simple AM or Double Sideband Suppressed Carri er DSBSC modulation External AM Source The rear panel AM INPUT is active at all times even in concert with any oth er modulation type The AM INPUT has an input voltage range of 5V A 5V input produces an output that is 100 of the programmed value a OV input turns the output will off 0 and at 5V input produces an output that is 100 of the programmed output a 180 phase change Applying voltag es from 0 to 5V will result in simple AM If the voltages are balanced around zero from 5V to 5V DSBSC modulation will result for good carrier sup pression the modulating signal must have an average value of zero The AM INPUT has a bandwidth of about 20 kHz INTERNAL AM The internal modulation generator can
116. e new calbyte value for this frequency is new calbyte old calbyte Vref Vpp The calbyte should be in the range 8000 to 23000 The calbyte 6 8 es Calibration im number for a given frequency is number 118 f 1000Hz 312500 Hz that is 313500 Hz 119 626000 Hz 120 etc 5 Set calbyte 215 to the same value as calbyte 214 Square Wave Symmetry This calibration corrects the symmetry of the DS345 s square wave output This calibration depends on frequency and is calibrated at 98 frequency points in the DS345 s frequency range This calibration should be done after the square wave amplitude calibration 1 Set the DS345 to square wave 1 kHz 10 Vpp Connect the DS345 s out put to the counter with a 50Q terminator Set the DS345 s frequency step size to 312500 Hz Set the counter to measure the pulse width of the square wave input At 97 frequencies between 1000 Hz and 30 001 000 Hz in 312500 Hz steps repeat the following procedure 4 Set the DS345 s output frequency Adjust the calbyte for this frequency so that the positive pulse width of the square wave is equal to the negative pulse width The calbyte should be in the range 0 to 4095 The calbyte num ber for a given frequency is number 412 f 1000Hz 312500 Hz that is 1000 Hz 412 313500 Hz 413 etc 5 Set calbyte 509 to the same value as calbyte 508 M Calibration ee 6 10 Mee Arbitrary Waveform Composer Hil ARBITRARY WAVEFORM COMPOSER SOF
117. e sine periods in the 1000 points AWC will now ask for the amplitude of the waveform The amplitude will be 10 Vpp After a brief calculation AWC will draw the waveform on the screen The display should show 10 sine periods along with new axis labels The screen shows the Peak to Peak amplitude of the waveform in Volts the minimum and maximum voltages of the waveform and the current file name The vertical scale is calculated automatically The horizontal scale has units of waveform points The numbers Min and Max in the corners of the screen are the minimum and maximum point number being displayed these units correspond to the RAM addresses in the DS345 s waveform memory The total number of points displayed is listed as are the total number of points in the waveform We are going to edit this waveform We want to invert it and then multiply by an exponential damping factor The waveform will be mirrored inverted Math allows mathematical operations on the waveform Make sure that there is a check mark in the Exp box and that multiply is selected We will multiply by an exponential damping The choices are ok AWC will ask for the damping factor The sine wave will be damped by exp 4 at its endpoint After a brief calculation AWC will draw the new waveform Throughout this example the Send Data and Trigger menus were disabled This is because the communications parameters have not been set Select the RS232 GPIB submenu from t
118. ed can make the TRIG D LED appear orange Trigger Input The rear panel TRIGGER input is a TTL compatible input An edge at this in put will trigger a BURST SWEEP if the trigger source is set to POS IN or NEG IN Trigger Output The rear panel TRIGGER output is a TTL compatible output that goes high when the DS345 triggers a BURST SWEEP and goes low again when the BURST SWEEP is complete This output is operational for all trigger sources 2 22 ES Modulation and Sweeps ARBITRARY MODULATION PATTERNS Introduction In addition to the usual sine square triangle and ramp waveforms the DS345 s AM FM and PM functions can modulate the output waveform with an arbitrary modulation pattern The arbitrary modulation pattern can only be set using a computer interface and the AMOD query command The com puter downloads a list of amplitude percentages frequencies or phase shifts to the DS345 The DS345 then modulates the waveform using these values To use arbitrary modulation the modulation type must be set to AM FM or PM and an arbitrary pattern must then be sent to the DS345 If no pattern has been loaded the DS345 will display the message arb corrupt SWEEP ON OFF enables the arbitrary modulation Switching to a different modula tion type or waveform after a pattern has been downloaded to the DS345 will erase the donwloaded pattern Modulation Rate Pressing RATE sets the modulation rate The value displayed when the modulation wave
119. edback R of 500 ohms over R629 which is 20 ohms To correct the AC response of the amplifier C601 R623 and P601 C600 are present in the feedback path The former decreases gain at high frequen cies and the latter increases it C611 is an adjustment for the overall band width of the amplifier At DC op amp U600 injects current into the feedback node via the Q618 Q619 buffer to ensure that the output DC level matches that of the input An output offset is also injected via the inverting input of U600 through R626 Trimmer pot P600 is a balance control designed to trim the DC current bal ance and 3rd harmonic distortion P602 also affects 3rd harmonic distortion by increasing the gain by decreasing feedback during peak excursions of the output The signal at J602 is a filtered sample of the output which is sent to the top board ADC for amplitude and offset control OUTPUT ATTENUATOR SHEET 7 OF 7 The amplifier output passes through a three stage 50 ohm attenuator con sisting of resistors and relays K701 K702 and K703 This configuration al lows up to 42 dB of attenuation in steps of 6 12 and 24 dB BERS S345 Circuitry TOP PC BOARD RIBBON CABLE ADCs and DACs SHEET 1 OF 7 JP100 and JP101 are the system interface and top board power supply con nectors to the bottom board respectively U109A is half of a 12 bit DAC that is used to generate analog voltages for system control The current output of the DAC is converted
120. ems not tested are the connections from the PC boards to the BNC connec tors the output attenuators the 40 MHz clock and phase locking circuitry the computer interfaces and the SYNC output driver AUTOCAL The DS345 s autocal routine calibrates the majority of the signal generation path including the DC offsets of the output amplifier the signal path offsets the offset and gain of the amplitude controls and the gain of the output am plifier These calibrations correct for any aging and temperature dependen cies of the DS345 s circuits Pressing any UNITS key when the AUTOCAL menu item is displayed starts the calibration Autocal is disabled during the first two minutes after power on to allow the DS345 to warm up an error will be displayed if autocal is started before this time Autocal takes about two minutes to execute and should end with the mes sage cal done note Be sure to have disconnected any signals from the External AM input during Autocal If AUTOCAL encounters a problem it will immediately stop and display an error message See the TROUBLESHOOT ING section pg 4 1 for a list and explanation of the error messages If the DS345 fails its AUTOCAL it still may be operated simply press any key to erase the error message However the error may be indicating a hardware problem that probably should be addressed The items not calibrated by the autocal procedure are the frequency depen dent amplitude corrections the doubler
121. enerator i Symbols you may find on SRS products Alternating current Caution risk of electric shock Frame or chassis terminal Caution refer to accompanying documents Earth ground terminal EEE DS345 Synthesized Function Generator i Safety and Preparation for Use WARNING Dangerous voltages capable of causing death are present in this instrument Use extreme caution whenever the instrument covers are removed This instrument may be damaged if operated with the LINE VOLTAGE SELECTOR set for the wrong ac line voltage or if the wrong fuse is installed LINE VOLTAGE SELECTION The DS345 operates from a 100V 120V 220V or 240V nominal ac power source having a line frequency of 50 or 60 Hz Before connecting the power cord to a power source verify that the LINE VOLTAGE SELECTOR card located in the rear panel fuse holder is set so that the correct ac input voltage value is visible Conversion to other ac input voltages requires a change in the fuse holder voltage card position and fuse value Disconnect the power cord open the fuse holder cover door and rotate the fuse pull lever to remove the fuse Remove the small printed circuit board and select the operating voltage by orienting the board so that the desired voltage is visible when it is pushed firmly back into its slot Rotate the fuse pull lever back into its normal position and insert the correct fuse into the fuse holder LINE FUSE Verify
122. ep size for the current parameter the STEP LED will be lit Pressing STEP SIZE again returns the display to the previ ously displayed parameter The step size may be changed by typing a new value while the STEP LED is lit Pressing the MODIFY UP ARROW key while the step size is displayed increases the step size to the next larger decade while pressing the MODIFY DOWN ARROW key will decrease the step size to the next smaller decade CW Function Generation Our first example demonstrates generating CW waveforms and the DS345 s data entry functions Connect the front panel FUNCTION output to an oscillo scope terminating the output into 50 ohms Turn the DS345 on and wait until the message TEST PASS is displayed 1 Press SHIFT DEFAULTS This recalls the DS345 s default settings 2 Press AMPL Then press 5 Vpp Displays the amplitude and sets it to 5 Vpp The scope should show a 5 Vpp 1 kHz sine wave 3 Press FUNCTION DOWN ARROW twice The function should change to a square wave and then a triangle wave 4 Press FREQ and then 1 O kKHz Displays the frequency and sets it to 10 kHz The scope should now display a 10 kHz triangle wave 1 1 BE Getting Startect 5 Press MODIFY UP ARROW The frequency will increment to 10 1 kHz The flashing digit indicates a step size of 100 Hz 6 Press STEP SIZE Observe that the step size is indeed 100 Hz The STEP LED should be on 7 Press 1 2 3 Hz Then press STEP
123. equency depends on the Function Frequency Range 1 wHz 30 200000000000 MHz 1 wHz 30 200000000000 MHz 1 wHz 100 000 000000 Hz 1 wHz 100 000 000000 Hz 10 MHz White Noise fixed 0 002329Hz 40 0 MHz sampling function selected as listed below Frequency is usually displayed by the DS345 with 1 mHz resolution Howev er if the frequency is below 1 MHz and the microhertz digits are not zero the DS345 will display the frequency with 1 wHz resolution At frequencies great er than 1 MHz the digits below 1 mHz cannot be displayed but the frequency still has 1 wHz resolution and may be set via the computer interfaces or by using the MODIFY keys with a step size less than 1 mHz If the function is set to NOISE the character of the noise is fixed with a band limit of 10 MHz The frequency is not adjustable and the FREQ display will read noise instead of a numerical value If the function is set to ARB the frequency displayed is the sampling fre quency of the arbitrary waveform This number is independent of the usual frequency it is the dwell time that the DS345 spends on each point in an ar bitrary waveform This sampling frequency must be an integer submultiple of the the 40 MHz clock frequency That is 40 MHz N where N 1 2 3 294 1 40 MHz 20 MHz 13 3333 MHz 10 MHz The DS345 will spend 2 10 es Function Setting il 1 Fsample on each point When a new sampling frequency value is entered the DS345
124. eration ie to enable the front panel press STEP SIZE Controlling programs may inhibit the ability to return to LOCAL operation by asserting the Local Lockout state LLO A linefeed character is sent with and End or Identify EOI to terminate strings from the DS345 Be certain that your GPIB controller has been configured to accept this sequence RS 232 PROBLEMS First make sure that the RS232 interface is enabled Press SHIFT RS232 to display the enable status line RS232 should be ON If not turn RS232 on using the MODIFY keys Second the RS 232 baud rate must be set to match that expected by the controlling computer The default baud rate is 9600 baud The DS345 always sends two stop bits 8 data bits and no parity and will correctly receive data sent with either one or two stop bits When connecting to a PC use a standard PC serial cable not a null modem cable The DS345 is a DCE Data Communications Equipment de vice and so should be connected with a straight cable to a DTE device Data Terminal Equipment The minimum cable will pass pins 2 3 and 7 For hardware handshaking pins 5 and 20 CTS and DTR should be passed Occasionally pins 6 and 8 DSR and CD will be needed these lines are al ways asserted by the DS345 BE Troubleshooting lls 4 6 PERFORMANCE TESTS INTRODUCTION The procedures in this section test the performance of the DS345 and com pare it to the specifications in the front of this man
125. error is dis played The waveform of the modulating function is selected with MODULATION WAVEFORM UP DOWN arrow keys If no LEDs are lit the selected modula tion type has no associated waveform BURST for example has no modula tion waveform Not all modulation types may use all modulation waveforms The allowable combinations are listed on the following page Note that ARB modulation waveforms can only be downloaded via the computer interfaces 2 13 EE Modulation and Sweeps I If no waveform has been downloaded when this modulation is enabled the message arb corrupt will be displayed see the ARBITRARY MODULATION section ce Single Ramp Triangle Sine Square Arb Linear Swp Table 1 Allowed modulation waveforms for each modulation type MODULATION RATE Pressing RATE displays and sets the modulation rate Use the keypad and unit indicators of Hz kHz or MHz or the MODIFY up down keys to set the modulation rate The modulation rate is the frequency of the modulation waveform For exam ple if the modulation type is AM the waveform a sine wave and the rate 1 kHz the modulating waveform will be a 1 kHz sine wave For sweeps the modulation rate is the inverse of the sweep time ie a 10ms sweep would be entered as 100 Hz Burst modulation has no associated modulation rate and the message not applic is displayed if RATE is pushed The modulation rate has a range of 0 001 Hz to 10 kHz for AM FM and PM The rang
126. es will be renumbered if necessary Duplicating a Vertex To duplicate a vertex enter the vertex number of the vertex to be copied Then with the vertex number active flashing press any UNITS key The ver tex will be duplicated both x and y and the vertex number incremented to display the new vertex Inserting a Vertex To insert a vertex in the middle of a waveform duplicate the vertex currently at the insertion point Then modify the new vertex to the desired value 2 32 VECTOR EDIT EXAMPLE ES Arbitrary Waveform Editing ay The following is a step by step example of creating a vector format wave form We will create a heartbeat waveform with 9 vertices The vertices will be 0 0 50 200 150 0 175 300 225 2000 275 50 425 225 500 0 800 0 In the example UNITS refers to any UNITS key To watch the waveform grow display the FUNCTION output on an oscilloscope Trig ger the scope on the SYNC output The waveform should look like the dia gram below when done 1 Press FUNCTION DOWN ARROW until ARB LED is lit 2 Press SHIFT ARB EDIT three times to display Arb clear line then press any UNITS key 3 Press SHIFT ARB EDIT and use MODIFY keys to set Entry to VECTOR 4 Press SHIFT ARB EDIT once 5 Press SHIFT RIGHT ARROW then 5 0 UNITS 6 Press STEP SIZE then 2 O O UNITS 7 Press SHIFT LEFT ARROW then MODIFY UP ARROW 8 Press SHIFT RIGHT AR
127. essing CLR any time a value is not being entered The table on the next page lists the DS345 calbytes Shown is the calbyte number name and meaning The chart also indicates which calbytes are automati cally adjusted by autocal M Calibration ee DS345 CALBYTES Number Name Autocal Meaning Oscillator Cal Tunes Oscillator Range 0 4095 5 V Ref Cal ADC Gain ADC Offset Value of 5 ref voltage Value 32768 Vref 5 00 ADC Gain correction ADC Offset correction lt lt zZ DC Offset Gain DC Offset offset DC ouput offset gain fix DC output offset offset fix lt lt Attenuator 0 dB Attenuator 6 dB Attenuator 12 dB Attenuator 18 dB Attenuator 24 dB Attenuator 30 dB Attenuator 36 dB Attenuator 42 dB Gain correction for 0 dB attenuator Gain correction for 6 dB attenuator Gain correction for 12 dB attenuator Gain correction for 18 dB attenuator Gain correction for 24 dB attenuator Gain correction for 30 dB attenuator Gain correction for 36 dB attenuator Gain correction for 42 dB attenuator 22222222 System amp DAC ASIC amp DAC Sine DC gain Square DC gain Bessel DC gain Waveform DAC offset Offset of system amplitude DAC Offset of ASIC amplitude DAC Sets the sinewave DC gain Sets the squarewave DC gain Sets the Bessel tri ramp arb DC gain Offset of waveform DAC lt lt lt lt lt lt NOTE The following calbytes are frequency dependent The table value for a particular frequency
128. etups running self test and autocalibration and setting the computer interfaces The fourth and last section describes front panel editing of arbitrary waveforms When the power is first applied to the DS345 the unit will display its serial number and ROM version for about three seconds The DS345 will then ini tiate a series of self tests of the circuitry and stored data The test should take about three seconds and end with the message TEST PASS If the self test fails the DS345 will display an error message indicating the nature of the problem see the TROUBLESHOOTING section for more details page 4 1 The DS345 will attempt to operate normally after a self test failure press ing any key will erase the error message TTL FUNCTION 40V max 50 Q The FUNCTION and SYNC BNCs are the DS345 s main outputs Both of these outputs are fully floating and their shields may be floated relative to earth ground by up to 40V Both outputs also have a 50Q output impe dance If the outputs are terminated into high impedance instead of 50Q the signal levels will be twice those programmed the FUNCTION output may also show an increase in waveform distortion The programmed waveform comes from the FUNCTION output while the SYNC output generates a TTL compatible 2 5 V into 50Q signal that is synchronous with the function out put The SYNC signal is suppressed if the function is set to NOISE or BURST modulation If the function is set to ARB
129. for at least 1 2 hour Set the DS345 for sine wave 10 MHz 1 Vpp 2 Attach the output of the DS345 to the frequency counter Terminate into 50Q Attach the reference frequency input of the counter to the frequency standard Set the counter for a 1s frequency measurement 3 The counter should read 10MHz 50Hz Record the result AMPLITUDE ACCURACY The following tests measure the accuracy of the DS345 output amplitude There are separate tests for sine square and ramp triangle The tests measure the accuracy of the amplitude as a function of frequency The sine wave test also measures the performance of the attenuators There is only a single test for triangle and ramp functions because they have the same sig nal path Frequency lt 100 kHz Connect the DS345 output to the voltmeter through the 50Q terminator After the DS345 has had at least 1 2 hour to warm up run the autocal procedure Then perform the following tests Sine Wave specification 0 2 dB 2 3 amplitude gt 5V 0 3 dB 3 4 amplitude lt 5V 1 Set the DS345 to sine wave 100Hz 3 54 Vrms 10Vpp 2 Read the AC voltage on the voltmeter Repeat at 1kHz and 10kHz and 100 kHz The readings should be between 3 459 and 3 621 Vrms 2 3 Record the results 3 Set the DS345 to 1 kHz Set the amplitude to 1 Vrms Read the voltmeter and record the results The amplitude should be between 0 966 and 1 034 Vrms Repeat at 0 5 Vrms 0 25 Vrms 125 mVrms 75 mVrm
130. form is set to ARB is different than the usual modulation rate The value displayed is the value of the modulation rate divider MRD which can be set between 1 and 223 1 8 388 607 This value sets the time the DS345 spends at each point in the arbitrary modulation wave form The time at each point is given by Type of Arb Modulation Time AM 150ns MRD FM 1 us MRD PM 250ns MRD Waveform List The ARB waveform is created by downloading a list of values via the comput er interface For ARB AM the values are percentages of the programmed am plitude The waveform may have up to 10 000 AM points For ARB FM the values are the frequencies to be output and must be a valid frequency for the selected function The waveform may have up to 1500 FM points For ARB PM the values are phase shifts relative to the current phase in the range 180 The waveform may contain up to 4000 PM points Downloading The waveform list may be downloaded to the DS345 via the RS232 or the GPIB interface The data format is discussed in the PROGRAMMING section under the AMOD command The PROGRAM EXAMPLES section pgs 3 5 provides examples of generating and downloading waveform data 2 23 EE Modulation and Sweeps DS345 AS A PULSE GENERATOR Introduction The DS345 can be easily used as a pulse generator Pulse widths down to 500 ns with rise fall times of 30 ns and repetition rates up to 10 kHz internally and 500 kHz externally triggered are possible
131. frequency and span The relationships between the frequencies are Center Frequency Stop Frequency Start Frequency 2 Span Stop Frequency Start Frequency Start Frequency Center Frequency Span 2 Stop Frequency Center Frequency Span 2 2 19 EE Modulation and Sweeps Start and Stop Frequencies To enter the sweep start frequency press START FREQ Set the stop fre quency by pressing SHIFT STOP F The start and stop frequencies may have any values that are allowed for the displayed waveform If the stop fre quency is greater than the start frequency the DS345 will sweep up while if the start frequency is larger the DS345 will sweep down Center Frequency and Span To set the sweep center frequency press SHIFT SWP CF The center fre quency may be set to any value allowed for the displayed waveform Set the sweep span by pressing SPAN The span value is restricted to sweep fre quencies greater than zero and less than or equal to the maximum allowed frequency If the span is positive the DS345 will sweep up if it is negative the DS345 will sweep down The MODIFY keys may be used to change the span pressing MODIFY UP will double the span while pressing MODIFY DOWN divides the span in half The MODIFY keys affect the span in oc taves the size of the step is the value displayed by the step size When the center frequency is changed the span is held constant while changing the span holds the center frequency constant
132. h sine wave 1 0 kHz span sine wave 45 0 span sine wave 1 cycle SINGLE 1 0 kHz RS232 9600 19 On Storing Setups Recalling Stored Settings To store the DS345 s current setup press STO followed by a location num ber in the range of 0 to 9 Pressing any of the UNITS key to enter the loca tion number the message Store Done indicates that all of the settings have been stored To recall a stored setting press RCL followed by the location number 0 9 Pressing any UNITS key enters the location number and the message re call done indicates that the complete settings have been recalled If nothing is stored in the selected location or the settings have become corrupted the DS345 will display rcl error 2 25 BMRB CT GPIB Setup To set the DS345 s GPIB interface press SHIFT GPIB Use the MODIFY up down keys to enable the GPIB interface Pressing SHIFT GPIB again displays the GPIB address Enter the desired address using the keypad or MODIFY keys The range of valid addresses is 0 to 30 NOTE If the DS345 does not have the optional GPIB RS232 interfaces the message no interface will be displayed when the GPIB menu is accessed The GPIB and RS232 interfaces are exclusive only one may be active at a given time the RS232 interface is automatically disabled when GPIB is ena bled RS232 Setup To set the DS345 s RS232 interface press SHIFT RS232 Use the MODIFY up down keys to enable the RS232 interface
133. have LabView installed at all continue with step 4 below 4 Inside the unzipped temporary directory navigate to the INSTALLER directory Inside this folder run SETUP EXE and follow the on screen instructions This section gives a quick introduction to using AWC The details of the menus and other functions are explained in succeeding sections 1 Double Click on the AWC icon The AWC display should appear This display consists of a menu 2 Select the Waveform menu 3 Select Sine bar and a graph screen The menu bar allows selection of various program options and functions The graph display shows the current arbitrary waveform with voltage on the vertical axis and point number on the horizontal axis Select a menu by placing the arrow cursor on that menu title and clicking the left mouse button Some of the menus are grayed and may not be selected because there is no waveform to edit and the communications parameters have not been set The arbitrary function will be a sine wave AWC will ask for the number of points in the waveform 7 1 ES Arbitrary Waveform Composer iis 4 Enter 1000 5 Enter 10 6 Enter 10 7 Select the Edit menu 8 Select Mirror 9 Select the Waveform menu 10 Select math 11 Select multiply and Exp 12 Click Okay 13 Enter 4 14 DONE Any number of points between 8 and 16300 may be entered AWC will ask for the number of complete periods in the waveform Ten complet
134. he Set DS345 menu to set the communication parameters according to your specific hardware configuration See the Set DS345 menu description for more information on establishing communication with the DS345 Once communication is established use these menu selections to send the data to the DS345 7 2 Me Arbitrary Waveform Composer Hi USERS GUIDE Hardware Requirements MENUS File Menu New Open Save Quit Edit Menu Clear Set x1 x2 to DC AWC is designed to run on Windows systems running XP 2000 Me 98 The DS345 Synthesized Function Generator must be equipped with option 01 GPIB and RS232 interfaces AWC communicates with the DS345 though an RS232 interface or a National Instruments hardware implementation of the GPIB interface Since the AWC software was written with National Instruments LabVIEW software development tools and utilizes the Virtual Instrument Software Architecture VISA interface running it requires that both the NI LabVIEW Run Time Engine version 6 1 as well as NI VISA version 2 6 or later be installed on your computer system See installation instructions for details AWC runs on all CGA EGA VGA HGC compatible graphics display hardware The display type is automatically determined when the program starts The file menu allows the user to store and recall arbitrary waveforms from disk New clears the current arbitrary waveform AWC will check with the user to be sure that the current waveform shou
135. he range allowed for a waveform gt 100 kHz for triangle and ramp a message will be displayed and the frequency will be set to the maximum al lowed for that function 8 Main Function BNC This output has an impedance of 50 If it is terminated into an impedance other than 50Q the output amplitude will be incorrect and may exhibit in creased distortion The shield of this output may be floated up to 40V rela tive to earth ground 9 Sync Output BNC This output is a TTL square wave synchronized to the main function output and has a 50Q output impedance The shield of this output may be floated up to 40V relative to earth ground 10 Status LEDs These six LEDs indicate the DS345 s status The LED functions are name function REM The DS345 is in GPIB remote state The STEP SIZE key re turns local control SRQ The DS345 has requested service on the GPIB interface ACT Flashes on RS232 GPIB activity ERR Flashes on an error in the execution of a remote command EXT CLOCK The DS345 has detected a signal at its TIMEBASE input and is trying to phase lock to it CLOCK ERR The DS345 is unable to lock to the signal at the TIMEBASE input This is usually because the signal is too far gt 2ppm from the nominal values of 10 5 3 33 2 5 or 1 25 MHz 11 Parameter Display This 12 digit display shows the value of the currently displayed parameter The LEDs below the display indicate which parameter is being viewed Error messages may also appear
136. ible irregularities 1 Connect the DS345 s output to the oscilloscope input and terminate in 50 2 Set the DS345 to sine 10 MHz 10 Vpp Set the scope to 2 V div vertical and 100ns div horizontal 3 The scope should display a sine wave with one cycle per horizontal divi sion and about five divisions peak to peak There should be no visible irreg ularities in the waveform Square Wave This procedure checks the square wave output for frequency rise time and aberrations 1 Connect the DS345 s output to the oscilloscope input and terminate in 50 2 Set the DS345 to square wave 1 MHz 10 Vpp Set the scope to 2V div 5 2 E Performance Tests Ml vertical and 200ns div horizontal 3 The scope should show two square waves about 5 division peak to peak 4 Increase the scope sensitivity to 1V div and measure the size of the over shoot at the beginning of the square wave It should be less than 0 5V peak to peak 5 Adjust the scope to 2 V div and 5ns div Measure the 10 to 90 rise time of the square wave It should be less than 15ns Amplitude Flatness This test provides a visual indication of the sine wave amplitude flatness 1 Connect the DS345 s output to the oscilloscope input and terminate in 50Q 2 Set the DS345 to sine wave 10Vpp Modulation to linear sweep with a sawtooth waveform Set the start frequency to 1Hz stop frequency to 30MHz and the rate to 100Hz Turn the DS345 s sweep ON 3 Set the scope
137. icrosoft C and uses National Instruments GPIB card Assumes DS345 is installed as device name DS345 include lt stdio h gt include lt string h gt include lt stdlib h gt include lt dos h gt include lt math h gt include lt float h gt include lt decl h gt National Instruments header file void main void int ds345 unsigned long data 1500 up to 1500 points 4 bytes each void main char cmd 40 int i number long sum double t center span S if ds345 ibfind DS345 lt 0 open National driver printf Cannot find DS345 n exit 1 number 1000 1000 points sum Ol initialize checksum s pow 2 0 32 0 scale factor center 50 0E3 50 kHz center freq span 10 053 10 kHz span now we will calculate 4 byte frequency data each point is given by value 2 32 freq 40 MHz for 1 0 i lt number itt t span 2 0 sin 6 2831853 double i double number delta freq t center center freq output frequency t 40 0E6 ratio to 40 MHz data i long s t sum data i data number sum store checksum sprintf cmd MENAO MTYP3 MDWF5 n make sure modulation off until after loading set FM arb WF 3 17 BM Program Examples ibwrt ds345 cmd strlen cmd send commands sprintf cmd AMOD d n number
138. ind DS345 lt 0 open National driver printf Cannot find DS345 n exit 1 number 1000 1000 points sum Ol initialize checksum s pow 2 0 16 0 scale factor span 90 0 90 deg span a Program Examples I since list is of phase CHANGES need to calculate initial phase of waveform and then calculate phase shifts old 0 0 initial sine wave value 0 sin 0 calculate 4 byte data values each value 2 16 delta phase for i 0 i lt number i new span sin 6 2831853 double i 1 double number 2 0 new phase t new old phase change old new save new phase for next time data i long s t sum data i update checksum data number sum store checksum sprintf cmd MENAO MTYP4 MDWF5 n make sure modulation off until after loading set PM arb WF ibwrt ds345 cmd strlen cmd send commands sprintf cmd AMOD d n number arb modulation command ibwrt ds345 cmd strlen cmd ibrd ds345 cmd 40 read back reply befor sending data ibwrt ds345 char data long 4 number 4 number of bytes 4 per data point 4 for checksum sprintf cmd MENA1 n ibwrt ds345 cmd strlen cmd EXAMPLE 4 Point Mode Arbitrary Waveform turn modulation on This program downloads an arbitrary in
139. ing description is of the 15 volt reg ulator but the other regulators function in an analogous manner The heart of the regulators is a three terminal regulator in this case U103 The adjust pin of the regulator is controlled by op amp U109 which compares the divid ed output of U103 to the 5 volt reference The op amp is heavily compensat ed so the work of regulation falls primarily on the regulator The logic supply for the interface board is provided by 3 terminal regulator U107 and comes from a separate chassis ground referenced winding of the power supply transformer T100 A line synchronous TTL signal is provided for triggering by U110A MICROPROCESSOR SYSTEM SHEET 2 OF 7 Instrument control is provided by U200 a Z8800 microprocessor with 64k bytes of ROM and 32k bytes of RAM The RAM is backed up by battery BT200 to store instrument settings U201 is the buffered data bus transceiv er and U205 generates the system port strobes U210A is a one shot that enables the front panel LEDs as long as the processor is running and writing to port 18H This shuts off the multiplexed front panel LEDs and prevents their failure if the processor should stop for any reason Power up down reset is provided by the reset circuit consisting of Q201 and Q202 On power up reset is released only after C204 charges through R210 from the 5 volt logic supply On power down Q202 discharges C204 through R211 Q202 is turned on by Q201 which uses the
140. ion data to DACS for output amplitude control and a modulation output mimic AMPLITUDE AND SWEEP DACS SHEET 4 OF 7 U401 is the modulation mimic output DAC and generates an analog repre sentation of the modulation being used This is necessary because wave form modulation is handled digitally in the ASIC so no analog modulation waveforms are actually used U412A performs fast amplitude control modu lation based on DDS modulation data The analog output of this DAC after being converted to a voltage output by op amp U410A is filtered by the 7th degree Bessel anti aliasing filter connected to U410B pin 7 This filter en sures that frequencies higher than 50 kHz do not appear in the modulation control output 12 bit DAC U109B provides the reference input to DAC U412A which is multiplied in U412A to set the system amplitude output For external amplitude control an analog voltage between 5 volts at rear pan el input J402 provides the reference to U109B after being buffered by U417A R428 pulls this input to the 5 volt reference when an external signal is not present The 5th degree Bessel filter at the output of U406A pin 1 performs the anti aliasing function for the modulation mimic output U409 selects the outputs that are presented to the SWEEP OUT and MOD OUT rear panel BNCs as well as the test signal applied to the system ADC input from U409 pin 4 8 5 BH S345 Circuitry U412B generates a 12 bit resolution analog out
141. ion did not converge or went out of range E Troubleshooting il Offset Cal Err2 4 The dc output offset control gain calibration did not converge or went out of range Offset Cal Err3 5 The ASIC amplitude DAC U412A offset calibration did not converge Offset Cal Err4 5 The system amplitude DAC U109B offset calibration did not converge Sine DC G Er 6 The sine wave path DC gain is outside of 40 to 25 from nominal or the calibration did not converge after the maximum allowed number of iterations Sqr DC G Err 6 The square wave path DC gain is outside of 40 to 25 from nominal or the calibration did not converge after the maximum allowed number of itera tions GPIB PROBLEMS First make sure that the GPIB interface is enabled Press SHIFT GPIB to display the enable status line GPIB should be ON If not turn GPIB on us ing the MODIFY keys Second the GPIB address of the DS345 must be set to match that expected by the controlling computer The default GPIB ad dress is 19 and so it is a good idea to use this address when writing pro grams for the DS345 Any address from 0 to 30 may be set in the GPIB menu To check the GPIB address press SHIFT GPIB twice to view the GPIB address The entry keys or MODIFY keys may be used to set the GPIB address The DS345 will ignore its front panel key pad when Remote Enable REN has been asserted by the GPIB This REMOTE state is indicated by the REM LED To return to LOCAL op
142. is played pressing a units key without entering a new value will displayed the amplitude in the new units This allows the amplitude display to be switched between Vpp Vrms and dBm without entering a new value 5 Shift Key The shift key is used to select the functions printed in gray above the keys Press SHIFT and then key to select the desired function for example SHIFT SWP CF to display the sweep center frequency When the SHIFT key is pressed the SHIFT LED will light This indicates that the keyboard is in shift mode Pressing SHIFT a second time will deactivate shift mode 6 Modulation Keys These keys control the DS345 s modulation capabilities The MODULATION TYPE up down arrow keys select the modulation type The MODULATION WAVEFORM up down arrow keys select the waveform of the modulating function The SWEEP ON OFF key turns the modulation on and off When the modulation is turned on the MOD SWP LED will light If the modulation parameters are not permitted for the selected output function an error mes sage will be displayed and modulation will not be turned on Some modula tion parameters are not relevant to all modulation types start frequency is not relevant to AM for example and the message NOT APPLIC will be displayed if they are selected 7 Function Keys These keys choose the main function output The FUNCTION up down arrow keys select between the output functions If the output frequency is set be yond of t
143. is given by TABLE BASE NUMBER Frequency Hz 312500 20 117 Sine Amplitude Sine wave amplitude correction 118 215 Square Amplitude Square wave amplitude correction 216 313 Doubler Offset Frequency doubler offset fix 314 411 Carrier Null Sine wave carrier null correction 412 509 Square Symmetry Square symmetry fix es Calibration im NECESSARY EQUIPMENT _ The following equipment is necessary to complete the adjustments and cali brations The suggested equipment or its equivalent may be used Instrument Critical Specifications Recommended Model Analog Oscilloscope 350 MHz Bandwidth Tektronix 2465 Time Interval Counter Frequency Range 20 MHz min SRS SR620 Time Interval Accuracy 1ns max FFT Spectrum Analyzer Frequency Range DC to 100 kHz SRS SR760 Amplitude Accuracy 0 2 dB Distortion lt 75 dB below reference RF Spectrum Analyzer Frequency Range 1 kHz to 100 MHz Anritsu MS2601 HP4195A Amplitude 0 5 dB Distortion and Spurious lt 70 dB DC AC Voltmeter 51 2 Digit DC accuracy Fluke 8840A True RMS AC to 100 kHz Thermal Converter Input Impedance 50 Q Ballantine 1395A 3 09 Input Voltage 3 Vrms Frequency DC to 30 MHz Accuracy 0 05dB 10 MHz Frequency Standard Frequency 10 MHz 001 ppm SRS FS700 Phase Noise lt 130 dBc 100Hz 50 Q Terminator 50 Q 0 2 1 Watt HP 11048C ADJUSTMENTS The following adjustments set the values of all of the variable components in the DS345 After an adjustment has been m
144. is to the DS345 clock output will reduce pulse to pulse jitter Arbitrary Waveform The other way to create pulses is using arbitrary waveforms which can be done from the front panel using vector entry mode or through the AWC soft ware This technique is a little more complicated and does not allow the same ease of changing pulse width or repetition rates but pulse widths down to 50 ns and externally triggered repetition rates up to 2 MHz are possible See oth er sections of this manual for instructions for arbitrary waveform generation and AWC software 2 24 INSTRUMENT SETUP Introduction Default Settings This section details the DS345 s default settings storing and recalling set tings setting the computer interfaces and running self test and autocal Pressing SHIFT DEFAULTS recalls the DS345 s default settings and clears any stored arbitrary waveforms The DS345 s default settings are listed be low Setting Frequency Arb Sampling Frequency Amplitude Offset Inversion Phase Modulation Enable Modulation Rate Modulation Type Modulation Waveform Sweep Parameters AM Parameters FM Parameters PM Parameters Burst Parameters Trigger Source Trigger Rate Interface Baud Rate GPIB Address Power on Status Clear Default Value 1 0 kHz 40 0 MHz 0 01 Vpp 0 0 V Off 0 0 Off 1 0 kHz AM Sine 1 0 Hz start frequency and start marker 100 0 kHz stop frequency and stop marker 50 dept
145. keyboard If you cannot talk to the DS345 via IBIC then your programs will not run Use the simple commands provided by National Instruments Use IBWRT and IBRD to write and read from the DS345 After you are familiar with these simple commands you can explore more complex programming com mands BM Program Examples EXAMPLE 1 Arbitrary Amplitude Modulation This program downloads an arbitrary AM pattern to the DS345 The modulating waveform is a sine wave The range of amplitude values will be 100 to 100 of full output making DSBSC modulation The pro gram calculates the AM pattern values sets the modulation type to AM modulation waveform to ARB down loads the pattern and enables modulation The program is written in C program to demonstrate arbitrary AM modulation Will generate a DSBSC sine wave signal Written in Microsoft C and uses National Instruments GPIB card Assumes DS345 is installed as device name DS345 include lt stdio h gt include lt string h gt include lt stdlib h gt include lt dos h gt include lt math h gt include lt float h gt include lt decl h gt National Instruments header file void main void function declaration int ds345 unsigned data 10000 up to 10000 points 2 bytes each void main char cmd 40 int i number sum double t if ds345 ibfind DS345 lt 0 open National driver printf Cannot fin
146. ld be discarded Open recalls a previously stored arbitrary waveform using a standard Windows open file dialog box The default extension for waveform files is txt however any other extension may be used Stored data file should contain all information necessary to restore AWC s state the waveform data sampling rate and trigger conditions Once a file is selected it will be loaded from the disk and displayed If the selected file has a form that is incompatible with AWC it will not be loaded and an error message will be displayed note Loading a file with an improper format may yield unpredictable results and or may cause the program to hang Refer to DATA FILE FORMAT on page 7 7 for the correct file format Note also that data files must use a period as the decimal point specifier e g 3 14159 not 3 14159 Save stores the displayed arbitrary waveform to disk using a standard Windows save file dialog box The data file stores the complete state of AWC the waveform data sampling rate and trigger parameters Recalling the file will completely restore AWC s state except communication parameters Quit exits the program The Edit menu is used to modify existing waveforms This menu is enabled only when there is an arbitrary waveform displayed on the screen Clears the current waveform from the graph and memory This sets a segment within the waveform to a DC value There are three parameters for this selection The first
147. lm 1 4W 5 R 123 4 00471 401 82 Resistor Carbon Film 1 4W 5 R 124 4 00471 401 82 Resistor Carbon Film 1 4W 5 R 125 4 00471 401 82 Resistor Carbon Film 1 4W 5 R 126 4 00138 407 10 0K Resistor Metal Film 1 8W 1 50PPM R 129 4 00715 407 22 1K Resistor Metal Film 1 8W 1 50PPM R 130 4 00164 407 20 0K Resistor Metal Film 1 8W 1 50PPM R 131 4 00281 407 11 8K Resistor Metal Film 1 8W 1 50PPM R 132 4 00138 407 10 0K Resistor Metal Film 1 8W 1 50PPM R 133 4 00083 401 47K Resistor Carbon Film 1 4W 5 R 134 4 00021 401 1 0K Resistor Carbon Film 1 4W 5 R 135 4 00021 401 1 0K Resistor Carbon Film 1 4W 5 R 136 4 00021 401 1 0K Resistor Carbon Film 1 4W 5 R 137 4 00021 401 1 0K Resistor Carbon Film 1 4W 5 R 138 4 00021 401 1 0K Resistor Carbon Film 1 4W 5 R 204 4 00030 401 10 Resistor Carbon Film 1 4W 5 R 205 4 00030 401 10 Resistor Carbon Film 1 4W 5 R 206 4 00075 401 39 Resistor Carbon Film 1 4W 5 R214 4 00088 401 51K Resistor Carbon Film 1 4W 5 R 220 4 00130 407 1 00K Resistor Metal Film 1 8W 1 50PPM R 221 4 00130 407 1 00K Resistor Metal Film 1 8W 1 50PPM R 222 4 00071 401 33 Resistor Carbon Film 1 4W 5 R 223 4 00071 401 33 Resistor Carbon Film 1 4W 5 R 224 4 00071 401 33 Resistor Carbon Film 1 4W 5 R 230 4 00032 401 100K Resistor Carbon Film 1 4W 5 9 16 ees Component Part List i R 231 4 00021 401 1 0K Resistor Carbon Film 1 4W 5 R
148. lution The DS345 is also relatively simple to use the following examples take the user step by step through some typical uses Data Entry Setting the DS345 s operating parameters is done by first pressing the key with the desired parameter s name on it FREQ for example to set the fre quency Some parameters are labelled above the keys in light gray To dis play these values first press the SHIFT key and then the labelled key SHIFT SWP CF for example displays the sweep center frequency Values are changed through the numeric keypad or the MODIFY keys To enter a value simply type the new value using the keypad and complete the entry by hitting one of the UNITS keys If the entry does not have units any of the UNITS keys may be pressed If an error is made pressing the CLR key re turns the previous value The current parameter value may also be increased or decreased with the MODIFY keys Pressing the UP ARROW key will in crease the value by the current step size while pressing the DOWN ARROW key will decrease the value by the current step size If the entered value is outside of the allowable limits for the parameter the DS345 will beep and dis play an error message Step Size Each parameter has an associated step size which may be an exact power of 10 1 Hz 10 Hz or 100 Hz for example or may be an arbitrary value If the step size is an exact power of 10 that digit of the display will flash Press ing STEP SIZE displays the st
149. mmands ae Program Examples Introduction The following examples demonstrate interfacing the DS345 via the GPIB in terface using the National Instruments GPIB card Using a different brand of card or the RS232 interface would be similar except for the program lines that actually send the data These examples are intended to demonstrate the syntax of the DS345 s command set To successfully interface the DS345 to a PC via the GPIB interface the in strument interface card and interface drivers must all be configured proper ly To configure the DS345 the GPIB address must be set in the GPIB menu The default GPIB address is 19 use this address unless a conflict occurs with other instruments in your system Make sure that you follow all the instructions for installing the GPIB card The National Instruments card cannot be simply unpacked and put into your com puter To configure the card you must set jumpers and switches on the card to set the I O address and interrupt levels You must run the program IB CONF to configure the resident GPIB driver for you GPIB card Please refer to the National Instruments manual for information In this example the fol lowing options must be set with IBCONF Device name ds345 Device address 19 EOS character OAh linefeed Once all the hardware and GPIB drivers are configured use IBIC This ter minal emulation program allows you to send commands to the DS345 direct ly from your computer s
150. modulate any of the DS345 s output functions except NOISE The modulating waveform may be a sine square triangle ramp or arbitrary pattern The rear panel MODULATION OUTPUT outputs a signal corresponding to the amplitude control voltage 100 of the output amplitude will produce an output of 5V zero output will produce OV and 100 output will produce 5V out Modulation Depth Press DEPTH to display and set to the AM modulation depth The value may be set using the keypad and units key or the MODIFY keys This val ue has a range of 100 with 1 resolution Positive values 0 to100 will set simple AM with a modulation percentage equal to the DEPTH Zero per cent depth corresponds to no modulation while 100 depth corresponds to modulating the output from full off to full on Negative values 1 to 100 will set DSBSC modulation with a modulation percentage equal to the depth Modulation Rate Press RATE to display and to set the frequency of the modulating function The frequency may be set with two digits of resolution from 0 001 Hz to 10 kHz EE Modulation and Sweeps FREQUENCY MODULATION Introduction The DS345 is capable of frequency modulating any of its output functions except NOISE and ARB using its internal modulation generator The modu lation waveform may be a sine square FSK triangle ramp or an arbitrary pattern The rear panel MODULATION OUTPUT outputs a signal with OV corresponding to the smallest freque
151. mp 4 noise 5 arbitrary Set output inversion on i 1 or off i 0 Sets the output offset to x volts Sets the current waveform phase to zero Sets the waveform output phase to x degrees Modulation control commands TRG BCNT i DPTH i FDEV x MDWF i MENA i MKSP MRKF i x MTYP i PDEV x RATE x SPAN x SPCF x SPFR x SPMK STFR x TRAT x TSRC i Triggers bursts single sweeps if in single trigger mode Sets the burst count to i Sets the AM modulation depth to i If i is negative sets DSBSC with i modulation Sets the FM span to x Hz Sets the modulation waveform 0 single sweep 1 ramp 2 triangle 3 sine 4 square 5 arbitrary 6 none Turns modulation on i 1 or off i 0 Sets the sweep markers to the extremes to the sweep span Sets marker frequency i to x Hz 0 mrk start freq 1 stop freq 2 center freq 3 span Sets the modulation type 0 lin sweep 1 log sweep 2 AM 3 FM 4 PM 5 Burst Sets the phase modulation span to x degrees Sets the modulation rate to x Hz Sets the sweep span to x Hz Sets the sweep center frequency to x Hz Sets the sweep stop frequency to x Hz Sets the sweep span to the sweep marker positions Sets the sweep start frequency to x Hz Sets the internal trigger rate to x Hz Sets the trigger source 0 single 1 internal 2 Ext 3 Ext 4 line Arbitrary Waveform and Mo
152. ncy output and 5V corresponding to the largest frequency output Frequency Span During FM the DS345 outputs a signal whose frequency range is centered about the programmed frequency SPAN sets the amount that the frequency varies from the center frequency The minimum frequency output will be the center frequency SPAN 2 while the maximum frequency will be the center frequency SPAN 2 The value SPAN 2 is commonly called the deviation that is SPAN Deviation x 2 The SPAN is displayed and set by pressing SPAN The SPAN may be set with 1 uHz resolution and has a limited range such that the output frequency is always greater than zero and less than or equal to the maximum allowed for the function selected 30 2 MHz for sine and square 100 kHz for triangle and ramp Modulation Rate Pressing RATE displays and sets the frequency of the modulating function The frequency may be set with two digits of resolution from 0 001 Hz to 10 kHz SE Voduiation and Sweeps Ii PHASE MODULATION Introduction The DS345 is capable of phase modulating any of its output functions ex cept NOISE and ARB using its internal modulation generator The modula tion waveform may be a sine square PSK triangle ramp or arbitrary pat tern see ARBITRARY MODULATION section for information about ARB patterns The rear panel MODULATION OUTPUT outputs a signal with OV corresponding to the largest negative phase deviation and 5V correspond ing to the largest p
153. nternal trigger rate generator 7 Press SHIFT TRIG RATE then 4 0 0 Hz Set the internal trigger rate generator to 400 Hz 8 Press SWEEP ON OFF Enable the burst The MOD SWP LED will light The scope should show two bursts of 10 cycles of a sine wave 9 Press SHIFT BRST CNT Display the burst count again 10 Press MODIFY DOWN ARROW twice There should now be 8 pulses in each burst 1 4 Introduction to Direct Digital Synthesis Introduction Direct Digital Synthesis DDS is a method of generating very pure wave forms with extraordinary frequency resolution low frequency switching time crystal clock like phase noise and flexible modulation As an introduction to DDS let s review how traditional function generators work Traditional Generators Frequency synthesized function generators typically use a phase locked loop PLL to lock an oscillator to a stable reference Wave shaping circuits are used to produce the desired function It is difficult to make a very high resolu tion PLL so the frequency resolution is usually limited to about 1 106 some sophisticated fractional N PLLs do have much higher resolution Due to the action of the PLL loop filter these synthesizers typically have poor phase jit ter and frequency switching response In addition a separate wave shaping circuit is needed for each type of waveform desired and these often produce large amounts of waveform distortion Arbitrary Waveforms Arbitrar
154. number of complete cycles in a burst is set by pressing SHIFT BRST CNT The number may be set from 1 to 30000 cycles The maximum time for a complete burst is 500s the time for a burst is easily computed from the following formulas Burst Time Burst Count for sine square triangle ramp Frequency Burst Time Burst Countx Waveform Points for ARB Sampling Frequency Waveform Starting Point The point in the waveform at which the burst starts the phase may be ad justed for sine square triangle and ramp waves For ARBs the burst always starts on the first waveform point Changing the PHASE changes the point at which the burst starts 0 000 degrees phase corresponds to the positive zero crossing of the function and values up to 359 999 degrees increment through the waveform PHASE values larger than 360 degrees are set to modulo 360 degrees Triggering a Burst Burst modulation is a triggered function and therefore a signal needs to ini tiate the burst The trigger generator can initiate a burst from the front panel TRIG key the internal rate generator the external trigger input or the pow er line frequency Setting the trigger generator is detailed in the TRIGGER GENERATOR section 2 22 The TRIG D LED flashes green each time a burst is triggered If the DS345 is triggered before the previous burst is com plete the TRIG D LED flashes red indicating a trigger error At high trigger rates a combination of triggers green
155. o 2048 5 If necessary adjust the optional oscillator coarse adjustment screw so that the frequency is within 1 Hz of 10 MHz Output Amplifier Bandwidth These adjustments correct the bandwidth of the output amplifier A complete calibration must be performed if these adjustments are changed All of the adjustments are on the bottom PCB and may be reached through holes in the shield Use an insulated adjusting screwdriver 1 Set the DS345 for square wave 8 Vpp 10 kHz Measure the DC voltage at the output of U600 pin 6 Adjust P600 to until this voltage is 0 0V 2 Connect the output of the DS345 to the oscilloscope with a 50Q termina tor Set the DS345 to square wave 8 Vpp 100 Hz Set the scope to 2 V div vertical and 5 ms div horizontal Adjust R639 for the squarest output wave form 3 Set the DS345 to 500 kHz Set the scope to 1 us div Adjust P601 for the squarest output waveform 4 Set the scope to 200ns div Adjust C611 for the fastest output risetime without excessive overshoots 5 Do a complete calibration of the DS345 Bessel Filter Adjustment This adjustment sets the bandpass of the DS345 s Bessel waveform filter The adjustments are on the top board Run autocal after these adjustments 1 Press SHIFT DEFAULTS This will recall the DS345 s default arbitrary waveform a square wave Set the DS345 to ARB waveform 8 Vpp 2 MHz sampling frequency Connect the DS345 s output to an oscilloscope with a 50Q terminator
156. o 8 1V pk pk minimum input level 10 MHz gt 1 Vpp sine into 50 Q Ovenized AT cut oscillator lt 0 01ppm 20 60 C lt 0 001ppm day lt 5x10 1s Allan Variance vii EM Specifications M GENERAL Interfaces RS232 C 300 to 19200 Baud DCE and IEEE 488 2 with free DOS Based Arbitrary Waveform Software All instrument functions are controllable over the interfaces Weight 10 Ibs Dimensions 8 5 x 3 5 x 13 WHL Power 50 VA 100 120 220 240 Vac 50 60 Hz viii eee Abridged Command List Mi Syntax Variables i j are integers Variable x is a real number in integer real or exponential notation Commands which may be queried have a in parentheses after the mnemonic The are not sent Commands that may only be queried have a after the mnemonic Commands which may not be queried have no Optional parameters are enclosed by Function Output Control Commands AECL AMPL x ATTL FREQ x FSMP x FUNC i INVT i OFFS x PCLR PHSE x Sets the output amplitude offset to ECL levels 1Vpp 1 3V offset Sets the output amplitude to x x is a value plus units indicator The units can be VP Vpp VR Vrms or DB dBm Example AMPL 1 00VR sets 1 00 Vrms Sets the output amplitude offset to TTL levels 5 Vpp 2 5 V offset Sets the output frequency to x Hz Sets the arbitrary waveform sampling frequency to x Hz Sets the output function 0 sine 1 square 2 triangle 3 ra
157. old boot turn the unit off Then while holding the CLR button turn the unit ON This procedure initializes the RAM and re calls all factory calibration values The Autocal procedure should be run af ter the unit warms up see INSTRUMENT SETUP section The following lists explain all of the error messages that the DS345 can gen erate The messages are divided into operational errors self test errors and autocal errors The messages are listed alphabetically These error messages may appear during normal front panel operation and generally are warnings of illegal parameter entries Meaning The output Vacl Vgc gt 5V Adjust either the offset or amplitude The stored arbitrary modulation pattern is corrupt The pattern is automatical ly erased by power down self test autocal or changing the modulation type or waveform An out of range value during editing of an arbitrary waveform Such as y val ue out of 2048 to 2047 range vertex x value lt previous vertex x value or vertex x value gt 16299 Tried to download more than 16300 points or 6144 vectors The stored arbitrary waveform has been corrupted Not a problem unless oc curs frequently Can be due to faulty battery or memory glitch The arbitrary waveform must be cleared before the edit mode can be changed The programmed burst time is outside of 1 us gt 500 s range Also if the fre quency of a burst waveform is gt 1 MHz The programmed center
158. om mand The rest of the sequence consists of parameters Multiple parame ters are separated by commas Parameters shown in are optional or may be queried while those not in are required Commands that may be quer ied have a question mark in parentheses after the mnemonic Com mands that may ONLY be queried have a after the mnemonic Commands that MAY NOT be queried have no Do not send or as part of the command All variables may be expressed in integer floating point or exponential for mats ie the number five can be either 5 5 0 or 5E1 The variables i and j usually take integer values while the variable x takes real number values Function Output Control Commands AECL The AECL command sets the output to the ECL levels of 1 V peak to peak with a 1 3 V offset That is from 1 8V to 0 8V AMPL x The AMPL command sets the output amplitude to x The value x must con sist of the numerical value and a units indicator The units may be VP Vpp VR Vrms or DB dBm For example the command AMPL 1 00DB will set the output to 1 0 dBm For arbitrary waveforms the amplitude may only be set in terms of peak to peak value Note that the peak AC voltage Vpp 2 plus the DC offset voltage must be less than 5 Volts Setting the amplitude to 0 Volts will produce a DC only no AC function output controlled by the OFFS command The AMPL query will return the amplitude in the currently displayed units For e
159. on Film 1 4W 5 Resistor Carbon Film 1 4W 5 Resistor Carbon Film 1 4W 5 Resistor Carbon Film 1 4W 5 Resistor Carbon Film 1 4W 5 9 6 ee Component Part List Mi R609 4 00031 401 100 Resistor Carbon Film 1 4W 5 R610 4 00021 401 1 0K Resistor Carbon Film 1 4W 5 R 611 4 00021 401 1 0K Resistor Carbon Film 1 4W 5 R612 4 00714 401 2 7 Resistor Carbon Film 1 4W 5 R613 4 00714 401 2 7 Resistor Carbon Film 1 4W 5 R614 4 00191 407 49 9 Resistor Metal Film 1 8W 1 50PPM R615 4 00726 407 57 6 Resistor Metal Film 1 8W 1 50PPM R616 4 00726 407 57 6 Resistor Metal Film 1 8W 1 50PPM R617 4 00191 407 49 9 Resistor Metal Film 1 8W 1 50PPM R618 4 00021 401 1 0K Resistor Carbon Film 1 4W 5 R619 4 00021 401 1 0K Resistor Carbon Film 1 4W 5 R620 4 00193 407 499 Resistor Metal Film 1 8W 1 50PPM R 621 4 00193 407 499 Resistor Metal Film 1 8W 1 50PPM R623 4 00164 407 20 0K Resistor Metal Film 1 8W 1 50PPM R624 4 00177 407 3 48K Resistor Metal Film 1 8W 1 50PPM R625 4 00177 407 3 48K Resistor Metal Film 1 8W 1 50PPM R626 4 00142 407 100K Resistor Metal Film 1 8W 1 50PPM R627 4 00142 407 100K Resistor Metal Film 1 8W 1 50PPM R628 4 00356 407 20 Resistor Metal Film 1 8W 1 50PPM R629 4 00356 407 20 Resistor Metal Film 1 8W 1 50PPM R630 4 00724 407 226 Resistor Metal Film 1 8W 1 50PPM R 631 4 00057 401 220 Resistor Carbon Film 1 4W 5 R632 4 00021 4
160. on the display When an error message is dis played you can return to the normal operation by pressing any key 2 6 es 0S345 FEATURES 12 Units LEDs These LEDs indicate the units of the displayed value If no LED is lit the num ber displayed has no units Rear Panel Features Re ch eee TTL ol TS 10MHz RELER E TOUA Sen TA FUSE 3 4A 100 120VAC or 3 8A 220 240VAC SS E G Ai C SWEEP MARKER BLANK LIFT 3 a SS IEEE 488 STD PORT GPIB RS232 DCE 8d Op 2s bits 1 Power Entry Module This contains the DS345 s fuse and line voltage selector Use a 1 amp fuse for 100 120 volt operation and a 1 2 amp fuse for 220 240 volt operation To set the line voltage selector for the correct line voltage first remove the fuse Then remove the line voltage selector card and rotate the card so that the correct line voltage is displayed when the card is reinserted Replace the fuse 2 External Inputs Trigger Input The trigger input is a TTL compatible input used to trigger modulation sweeps and bursts This input has a 10 kQ input impedance The shield of this input is tied to that of the function output and may be floated up to 40V relative to earth ground AM Input The AM input controls the amplitude of the function output This input has a 100 kQ input impedance and a 5V range where 5V sets the output to 100 of the front panel setting OV sets the output to 0 and 5V sets the out put to 100 of the setting
161. ork SIP 1 4W 2 Isolated N 402 4 00255 421 100X3 Res Network SIP 1 4W 2 Isolated N403 4 00255 421 100X3 Res Network SIP 1 4W 2 Isolated N404 4 00255 421 100X3 Res Network SIP 1 4W 2 Isolated N405 4 00255 421 100X3 Res Network SIP 1 4W 2 Isolated P600 4 00012 441 20K Pot Multi Turn Trim 3 8 Square Top Ad P 601 4 00012 441 20K Pot Multi Turn Trim 3 8 Square Top Ad P602 4 00011 441 10K Pot Multi Turn Trim 3 8 Square Top Ad 9 4 eee Component Part List i PC1 7 00366 701 DS345 BOTTOM Printed Circuit Board PC2 7 00368 701 DS345 FP Printed Circuit Board Q100 3 00177 321 2N2222 Transistor TO 18 Package Q200 3 00140 325 2N2369A Transistor TO 92 Package Q201 3 00026 325 2N5210 Transistor TO 92 Package Q202 3 00026 325 2N5210 Transistor TO 92 Package Q300 3 00021 325 2N3904 Transistor TO 92 Package Q301 3 00480 322 MPS6652 Transistor TO 39 Package Q302 3 00480 322 MPS6652 Transistor TO 39 Package Q303 3 00480 322 MPS6652 Transistor TO 39 Package Q304 3 00480 322 MPS6652 Transistor TO 39 Package Q305 3 00480 322 MPS6652 Transistor TO 39 Package Q306 3 00480 322 MPS6652 Transistor TO 39 Package Q600 3 00015 322 2N5583 Transistor TO 39 Package Q601 3 00447 322 2N5943 Transistor TO 39 Package Q602 3 00021 325 2N3904 Transistor TO 92 Package Q603 3 00022 325 2N3906 Transistor TO 92 Package Q604 3 00021 325 2N3904 Transistor TO 92 Package Q605 3 00022 325 2N3906 Transistor TO 92 Pack
162. ositive phase deviation Phase Span During PM the DS345 outputs a signal whose frequency is centered about the programmed frequency SPAN sets the amount that the phase varies rel ative to zero phase The minimum phase shift output will be SPAN 2 while the maximum phase shift output will be SPAN 2 The value SPAN 2 is com monly called the deviation that is SPAN Deviation x 2 The SPAN is dis played and set by pressing SPAN The value of the SPAN may be set with 0 001 resolution with a range of 0 to 7199 999 Modulation Rate Press RATE to display and set the frequency of the modulating function The frequency may be set with two digits of resolution in the 0 001 Hz to 10 kHz range EE Modulation and Sweeps i BURST MODULATION Introduction The DS345 generates tone bursts of any of its periodic output functions The frequency of the output function is limited to 1 MHz for sine and square waves 100 kHz for triangles and ramps and no limits for ARBs When a trig ger signal is received the DS345 initiates a burst starting at a specific point phase in the output waveform outputs the exact number of programmed waveform cycles and then stops The rear panel TRIGGER OUTPUT gener ates a TTL compatible signal that goes high when the burst is triggered and low when the burst is complete This signal may be used to synchronize ex ternal equipment to the burst The SYNC output is not active during tone bursts Burst Count The
163. output and allows generation of extremely pure sine waves The output of the Cauer filter is then frequency doubled by an analog multiplier This multiplies the DAC s 0 15 MHz output frequency range to the final 0 30 MHz range How ever the Cauer filter has very poor time response and is only useful for CW waveforms Therefore the Bessel filter was chosen for its ideal time re sponse eliminating rings and overshoots from stepped waveform outputs This filter limits the frequency of arbitrary waveforms to 10 MHz and rise times to 35 ns The output of the filters pass to an analog multiplier that controls the ampli tude of the waveform This multiplier controls the waveform amplitude with an AM signal that may come from either the ASIC or the external AM input This allows both internally and externally controlled amplitude modulation The amplitude control is followed with a wide bandwidth power amplifier that out puts 10 V peak to peak into a 50 ohm load with a rise time of less than 15 ns The output of the power amplifier passes through a series of three step atten uators 6 12 and 24 dB that set the DS345 s final output amplitude The post amplifier attenuators allow internal signal levels to remain as large as possible minimizing output noise and signal degradation Square waves and waveform sync signals are generated by discriminating the function waveform with a high speed comparator The output of the com parator passes to the
164. p down arrow keys A decimal point indicates the most recently re ceived character Communication with the DS345 uses ASCII characters Commands may be in either UPPER or lower case and may contain any number of embedded space characters A command to the DS345 consists of a four character command mnemonic arguments if necessary and a command terminator The terminator may be either a carriage return lt cr gt or linefeed lt lf gt on RS232 or a linefeed lt If gt or EOI on GPIB No command processing occurs until a command terminator is received All commands function identically on GPIB and RS232 Command mnemonics beginning with an asterisk are IEEE 488 2 1987 defined common commands These commands also func tion identically on RS232 Commands may require one or more parameters Multiple parameters are separated by commas Multiple commands may be sent on one command line by separating them by semicolons The difference between sending several commands on the same line and sending several independent commands is that when a command line is parsed and executed the entire line is executed before any other device action proceeds 3 1 EM Programming Commands There is no need to wait between commands The DS345 has a 256 charac ter input buffer and processes commands in the order received If the buffer fills up the DS345 will hold off handshaking on the GPIB and attempt to hold off handshaking on RS232 If the buffer ove
165. positions The sweep now goes from 200 kHz to 900 kHz This function allows zooming in on any feature in the sweep without entering the frequencies Tone Bursts This example demonstrates the DS345 s tone burst capability The DS345 can produce a burst of 1 to 30 000 cycles of any of its output functions The bursts may be triggered by the internal rate generator the line frequency a front panel button or an external rising or falling edge The TRIGGER output goes high when the burst is triggered and low when the burst is over Connect the DS345 s FUNCTION output to an oscilloscope terminating the output into 50 ohms Set the sensitivity to 2V div Connect the rear panel TRIGGER output to the scope and set 2V div Trigger the scope on the rising edge of the TRIGGER output Set the scope timebase to 0 5ms div 1 Press SHIFT DEFAULTS This recalls the DS345 s default settings 2 Press AMPL then 5 Vpp Set the amplitude to 5Vpp 3 Press FREQ then 1 0 KHz Set the output frequency to 10 kHz This will be the frequency of the tone BE Getting Startect 4 Press SWEEP MODE DOWN ARROW three Set the modulation type to BURST times 5 Press SHIFT BRST CNT Then 1 O Hz Set the number of pulses in the burst to 10 Any of the units keys may be used to terminate the en try 6 Press SHIFT TRIG SOURCE Then press Display the burst trigger source Then change the MODIFY UP ARROW source from single trigger to the i
166. pp OV offset 2 Set the DS345 to 26 662 MHz Set the spectrum analyzer to 26 662 MHz center frequency 100 kHz span Measure the amplitude of the spurious sig nals and verify that they are lt 50 dBc 3 Set the DS345 to 20 004 MHz Set the spectrum analyzer to 20 004 MHz 100 kHz span Measure the amplitude of the spurious signals and verify that they are lt 50 dBc 4 Set the DS345 to 18 MHz Set the spectrum analyzer to sweep from 1kHz to 100 MHz Ignoring the harmonics of the fundamental at 36MHz 54 MHz 72 MHz and 90 MHz measure the amplitude of the spurious signals and verify that they are lt 50 dBc HARMONIC DISTORTION This test measures the DS345 s sine wave harmonic distortion specification lt 55 dBc frequency lt 100 kHz lt 45 dBc frequency 0 1 to 1 MHz lt 35 dBc frequency 1 to 10 MHz lt 25 dBc frequency 10 to 30 MHz 1 Connect the DS345 output to the FFT analyzer input with a 50Q termina tor Set the DS345 to sine wave 100Hz 1 Vpp 2 Adjust the FFT analyzer to view the fundamental and its harmonics Verify that all harmonics are below 55 dBc 3 Repeat step 3 at 1 kHz and 10 kHz 4 Connect the DS345 output to the RF spectrum analyzer input Set the DS345 to 50 kHz Verify that the harmonics are at least 55 dBc 5 Set the DS345 to 500 kHz 5 MHz 15 MHz and 30 MHz and verify that all harmonics are at least 45 dBc 35 dBc 25 dBc and 25 dBc respectively Record the results
167. put that is used to fix up the offset present in the frequency doubler multiplier see sheet 6 The 50 kHz Bessel filter at the output of U413A pin 1 again is an anti aliasing filter for this output U403 generates control bits for the DACs and also for relays on sheet 6 U415 generates the proper write and chip select logic for DAC U412 from the outputs of U403 pins 15 and 16 DDS WAVEFORM DAC SHEET 5 OF 7 The DDS waveforms are generated by U500 a 12 bit ECL DAC The TTL waveform data from the ASIC waveform RAMS is latched to eliminate data timing skew by U505 and U506 and converted to ECL levels by U502 U503 and U504 N500 N501 and N502 serve to limit the input edge rates to the DAC in order to reduce data feedthrough to the DAC analog circuitry which is a source of output contamination U501 produces a 1 0 volt refer ence for U500 and the differential outputs at pins 6 and 7 are sent to the waveform output anti aliasing filters Bypass caps for the various power supplies are also listed on this sheet and are spread throughout the printed circuit board DDS OUTPUT FILTERS AND DOUBLER SHEET 6 OF 7 There are two filters for the DDS waveform DAC output selected by relays U602 and U603 The 10 MHz 7th degree Bessel filter is used for arbitrary functions and ramps and triangles and the 9th degree 16 5 MHz Cauer fil ter filters the sine outputs The Bessel filter s group delay characteristics are desirable for functions
168. r Carbon Film 1 4W 5 R111 4 00138 407 10 0K Resistor Metal Film 1 8W 1 50PPM R112 4 00470 407 10 5K Resistor Metal Film 1 8W 1 50PPM R113 4 00057 401 220 Resistor Carbon Film 1 4W 5 9 5 EE Component Part List R114 R115 R118 R119 R 120 R 200 R 201 R 203 R 204 R 205 R 206 R 207 R 208 R 209 R 210 R211 R212 R 213 R214 R215 R 300 R 301 R 302 R 303 R 304 R 305 R 306 R 307 R 308 R 309 R 310 R 311 R 419 R 420 R 421 R 422 R 423 R 424 R 425 R 426 R 427 R 428 R 600 R 601 R 602 R 603 R 604 R 605 R 606 R 607 4 00021 401 4 00032 401 4 00032 401 4 00081 401 4 00021 401 4 00079 401 4 00034 401 4 00722 401 4 00034 401 4 00034 401 4 00034 401 4 00032 401 4 00034 401 4 00034 401 4 00032 401 4 00021 401 4 00034 401 4 00034 401 4 00034 401 4 00034 401 4 00041 401 4 00041 401 4 00041 401 4 00041 401 4 00041 401 4 00041 401 4 00034 401 4 00034 401 4 00034 401 4 00034 401 4 00086 401 4 00034 401 4 00053 401 4 00053 401 4 00053 401 4 00021 401 4 00021 401 4 00021 401 4 00021 401 4 00471 401 4 00112 402 4 00034 401 4 00031 401 4 00031 401 4 00031 401 4 00031 401 4 00031 401 4 00048 401 4 00714 401 4 00714 401 1 0K 100K 100K 470 1 0K 4 7K 10K 43K 10K 10K 10K 100K 10K 10K 100K 1 0K 10K 10K 10K 10K 150 150 150 150 150 150 10K 10K 10K 10K 51 10K 200 200 200 1 0K 1 0K 1 0K 1 0K 82 47 10K 100 100 100 100 100 2 2K 2 7 2 7
169. rflows the buffer will be cleared and an error reported Similarly the DS345 has a 256 character output buf fer to store output until the host computer is ready to receive it If the output buffer fills up it is cleared and an error reported The GPIB output buffer may be cleared by using the Device Clear universal command The present value of a particular parameter may be determined by querying the DS345 for its value A query is formed by appending a question mark to the command mnemonic and omitting the desired parameter from the command If multiple queries are sent on one command line Separated by semicolons of course the answers will be returned in a single response line with the individual responses separated by semicolons The default re sponse terminator that the DS345 sends with any answer to a query is car riage return linefeed lt cr gt lt If gt on RS232 and linefeed plus EOI on GPIB All commands return integer results except as noted in individual command de scriptions Examples of Command Formats MRKF1 1000 0 lt lf gt Sets the stop marker to 1000 Hz 2 parame ters MRKF 1 lt lf gt Queries the stop marker frequency query of 2 parameter command IDN lt lf gt Queries the device identification query no pa rameters TRG lt lf gt Triggers a Sweep no parameters FUNC 1 FUNC lt lf gt Sets function to square wave 1 then queries the function Programming Errors The DS345 reports two types
170. rm can be between 8 and 16300 points long and can contain a specified number of complete sine wave cycles The maximum number of cycles is limited so that each cycle has at least 8 points The waveform amplitude in Volts peak to peak is also entered The waveform will have zero DC offset Produces an exponentially shaped pulse The user is asked for three parameters The waveform can be between 8 and 16300 points long The exponential damping factor b is then set The waveform will be reduced or increased by a factor exp b at its endpoint where b is limited to the range 50 to 50 The waveform amplitude in Volts peak to peak is entered The waveform will have zero DC offset level This selection produces an exponentially damped sinewave Four parameters are entered The number of points number of cycles and amplitude are the same as for the normal sine function The fourth parameter is the damping factor b The waveform will be reduced or increased by a factor exp b at its endpoint where b is limited to the range 50 to 50 This selection generates a pulse train The pulse train can have between 1 and 100 transitions state changes AWC first asks for the number of points in the waveform and the waveform amplitude The user is then asked for the transition locations pulse edges in the waveform The first transition always has a positive slope If a negative starting transition is needed apply the mirror function after the waveform i
171. rum analyzer using a 50Q terminator Set the analyzer to display 0 to 2 kHz 2 Adjust calbyte 314 to minimize the 1 kHz carrier amplitude 3 Connect the DS345 s output to the RF spectrum analyzer Set the DS345 s frequency step size to 312500 Hz Set the frequency to 313500 Hz At 96 frequencies between 313500 Hz and 30 001 000 Hz in 312500 Hz steps repeat the following procedure 4 Set the spectrum analyzer center frequency to the programmed frequency 2 Set the span to 100 kHz 5 Adjust the appropriate calbyte to minimize the carrier frequency compo nent at f 2 ignore any nearby spurs The calbyte has a range of 0 to 4095 The calbyte number for a particular frequency is 314 f 1000Hz 312500 Hz that is 313500 Hz 315 626000 Hz 316 etc 6 Step to the next frequency and reset the analyzer Continue until 30 001 000 Hz and calbyte 410 7 Set calbyte 411 to the same value as calbyte 410 M Calibration ee Sinewave Amplitude This calibration corrects the flatness of the DS345 s sinewave output This calibration depends on frequency and is calibrated at 98 frequency points in the DS345 s frequency range The carrier null calibration should be done be fore this calibration 1 Set the DS345 to sine wave 1 kHz 3 Vrms 0 V offset Set the frequency step size to 312500 Hz Connect the DS345 s output to the thermal convert er and the thermal conveter output to the DC voltmeter 2 Set calbyte 20 to 16384 3
172. s specification 6 frequency lt 20 MHz 15 frequency gt 20 MHz 1 Connect the DS345 s output to the oscilloscope with a 50Q terminator Set the DS345 to square wave 1 kHz 10Vpp Set the scope to 2V div and 0 1ms div 2 Step the DS345 s frequency in 2 MHz steps from 1kHz to 30 001 MHz 5 6 E Performance Tests Ml DC OFFSET ACCURACY DC Only DC AC SUBHARMONICS 3 Verify that the DS345 s output is within 6 of the 1kHz amplitude for fre quencies less than 20 MHz and within 15 for frequencies from 20 to 30 MHz This test measures the accuracy to the DS345 s DC offset function specification 1 5 of setting 0 2mV 1 Connect the DS345 s output to the voltmeter with a 50Q terminator Set the DS345 to 0 0V amplitude 2 Set the DS345 to 5V offset Read the voltmeter and record the result The result should be between 4 925V and 5 075V 3 Set the DS345 to 5V offset Read the voltmeter and record the result The result should be between 5 075V and 4 925V 4 Set the DS345 to OV offset Read the voltmeter and record the result The result should be between 0 2 mV and 0 2mV specification lt 80mV at full output 1 Connect the DS345 s output to the voltmeter with a 50Q terminator Set the DS345 to sine wave 1 kHz 10Vpp OV offset Set the voltmeter to meas ure DC voltage 2 Measure the offset voltage and verify that it is between 80mV and 80mV Record the result 3 Repeat step 2 at
173. s 40 mVrms and 25 mVrms Record the results They should be within 3 4 of the set values HI Performance Tests Square Wave specification 3 1 Set the DS345 to square wave 100Hz 5Vrms 10 Vpp 2 Read the AC voltage on the voltmeter Repeat at 1 kHz and 10kHz The readings should be between 4 85 and 5 15 Vrms Triangle Ramp Waves specification 3 1 Set the DS345 to triangle wave 100Hz 2 89Vrms 10 Vpp 2 Read the AC voltage on the voltmeter Repeat at 1 kHz and 10kHz The readings should be between 2 80 and 2 97 Vrms Frequency gt 100 kHz Sine Waves specification 0 2 dB 2 3 frequency lt 20 MHz 0 5 dB 6 frequency gt 20 MHz 1 Connect the DS345 s output to the thermal converter because the conver tor has a 50Q impedance no terminator is needed Connect the thermal converter output to the voltmeter using the most sensitive voltmeter range since the nominal signal level is about 7mV DC Allow the DS345 at least 1 2 hour to warm up 2 Set the DS345 to sine wave 1 kHz 3 00 Vrms Allow the thermal convert er 15 seconds to stabilize and record the result as the 1kHz reference value 3 Step the DS345 s frequency in 2 MHz steps from 1kHz to 30 001 MHz Al low the thermal converter to stabilize at each frequency and record the re sults 4 Verify that the readings are within 4 2 of the 1 kHz reading for frequen cies below 20 MHz and within 6 3 for frequencies above 20 MHz Square Wave
174. s are easily created using the Arbitrary Waveform Composer Software When the function is set to ARB the displayed frequency is the arbitrary waveform sampling frequency This number is not related to the normal waveform frequency but is the time that the DS345 dwells at each point in the arbitrary waveform This sampling frequency must be an integer submulti ple of the the 40 MHz clock frequency That is 40 MHz N where N 1 2 3 234 1 for example 40 MHz 20 MHz 13 3333 MHz 10 MHz The DS345 will spend 1 Fsample on each point 40 MHz 25 ns 20 MHz 50 ns etc When a new sampling frequency value is entered the DS345 will round the value to the nearest integer submultiple of 40 MHz The time needed to re peat a complete waveform is simply points in waveform Fsample During arbitrary waveform generation the front panel SYNC output generates a negative going 5V to OV 25ns pulse at the start of the arbitrary waveform Pressing SHIFT ARB EDIT repeatedly cycles through the three lines of the EDIT menu The first menu line allows selecting the ARB waveform storage mode Simply select POINT or VECTOR using the MODIFY up down keys The arbitrary waveform must be cleared before the storage mode can be changed see be low The third line of the EDIT menu allows the current ARB waveform to be cleared Pressing any of the UNITS keys with this line displayed clears the current waveform The second line of the EDIT menu allows
175. s controlled by U205 based on the output amplitude across the L203 C204 tank This signal is discriminated by comparator U200 which provides the 40 MHz differential ECL clock used throughout the system The ECL output of comparator U200 is sent directly to the waveform DAC clock inputs This is to ensure that the clock at the DAC is very pure as the quality of the DDS output is a direct reflection of the purity of the clock used for the DAC The rest of the system uses TTL clocks that are provided by ECL to TTL converters U209A and U209B U208 a FAST octal buffer is used to delay the TTL clock in 3 5 ns steps in order to provide variable clock timing for the DDS DAC data latches and the DDS ASIC U405B divides the 40 MHz by two to generate the 20 MHz clock used for the system microprocessor This signal is also sent to counter U202 to generate the system 2 5 and 10 MHz as well as the 1 25 MHz output to drive the sam pling phase detector used to lock the unit to an external clock source U207 buffers the 10 MHz output which is coupled to the rear panel 10 MHz output via tuned circuit L206 and C219 and transformer T202 U207 also buffers the input signals from either the optional internal oscillator at pin 12 or an external input at J201 before the signals pass to the sampling gate 8 4 ES 0245 circuitry U206 The sampling phase detector is made up primarily of U206 The selected in put at U206 pin 1 or 13 is chopped by the RCO output
176. s created The math selection applies mathematical operations to the current waveform This selection is disabled when there is no waveform The user may mirror the waveform multiply by 1 or may add subtract or multiply the waveform by a constant sine square triangle sawtooth or exponential wave These operations may take place over the entire waveform or just a segment 7 4 Mee Arbitrary Waveform Composer Hi Send Data Menu Waveform ASCII file Set DS345 Menu Sampling Frequency RS232 GPIB Use the math functions by selecting the desired function with the mouse and clicking Okay Several parameters must be entered the starting point number on which the operation should take place the number of points over which the function should operate and the amplitude of the function Exponentials also require that the damping factor b be entered If the amplitude of the resultant waveform exceeds the range of the DS345 an error message will be displayed The selections in the send data menu allow transmitting the arbitrary waveform to the DS345 The Send Data menu is enabled only when the communications parameters have been set in the Set DS345 This selection sends the current arbitrary waveform to the DS345 When the waveform is sent to the DS345 the state of the DS345 is set to match that of AWC That is the DS345 s sampling rate and trigger parameters are set to match the settings in AWC This selection is disabled if no
177. ses where the calbyte value is determined to be greater than 32767 enter the value cal byte value 65536 5 00 V Reference Calibration This procedure measures the value of the 5 0 V reference voltage that the DS345 uses for its internal A D converter calbyte 1 1 Measure the DC voltage at U103 pin 1 top board 2 The new value for calbyte 1 is Calbyte 1 32768 DC voltage 5 00 Clock Calibration This procedure sets the frequency of the DS345 s internal 10 MHz clock The procedure is identical for standard and optional oscillators Be sure that the DS345 has been completely reassembled and warmed up for at least 1 2 hour before this calibration is started 1 Connect the DS345 s 10 MHz output to the frequency counter input with a 50Q terminator Use the frequency standard as the counter s timebase 2 Adjust the value of calbyte 0 so that the frequency is within 1 Hz of 10 MHz 0 01 Hz for optional oscillators The range of calbyte 0 is 0 to 4095 If the clock cannot be calibrated with a value in this range do the clock adjust ment procedure Attenuator Calibration This procedure calibrates the DC value of the DS345 s output attenuators If the current calbyte value is negative use the value old calbyte 65536 in the following calculations 1 Connect the output of the DS345 to a DC voltmeter Do not use a 50Q terminator Set the DS345 to sine wave 1 kHz O Vpp 5 V offset 2 Record the DC voltage Record this value
178. sing the MODIFY UP arrow key adds the step size to the current value while pressing the MODIFY DOWN arrow key subtracts the step size from the current value If the step size is set to an exact power of 10 1 10 or 100 for example the corresponding digit of the display will flash To change the step size display the step size and then either enter a new value with the ENTRY keys or the MODIFY keys Pressing the MODIFY UP arrow while the step LED is lit will increase the step size to the next larger decade while pressing the MODIFY DOWN arrow will decrease the step size to the next smaller decade The MODIFY UP DOWN arrows also select be tween different menu selections ie trigger source Sometimes the parame ter display will have more than one parameter displayed at a time and the SHIFT LEFT and SHIFT RIGHT keys will select between these values The numeric keypad allows for direct entry of the DS345 s parameters To change a parameter value simply type the new value using the keypad The value is entered by terminating the entry with one of the UNITS keys A typ ing error may be corrected by using the CLR key The key may be select ed at any time during number entry The UNITS keys are used to terminate numeric entries Simply press the key with the desired units to enter the typed value Some parameters don t have BM Cua any associated units and any of the units keys may be used to enter the value When the amplitude is d
179. square wave output specification rise time lt 15 ns overshoot lt 5 of peak to peak output 1 Connect the output of the DS345 to the 350 MHz oscilloscope with a 50Q terminator Set the DS345 to square wave 1 MHz 10 Vpp 2 Set the oscilloscope to 2 V div vertical and 5 ns div horizontal Measure the time between the 10 and 90 points and verify that it is less than 15ns Record the results 3 Set the oscilloscope to 1 V div vertical and 100 ns div horizontal Verify that the overshoots and undershoots are less than 500 mV Record the re sults SQUARE WAVE SYMMETRY This test measures the symmetry of the square wave output specification lt 1 of period 4ns 1 Connect the output of the DS345 to the A input of the time interval counter and terminate into 50Q Set the DS345 to square wave 1 MHz 5 Vpp 2 Set the time interval counter to measure the positive width of the A input Record the reading 3 Set the time interval counter to measure the negative width of the A input This reading should be equal to the reading in step 2 lt 14 ns Record the result AM ENVELOPE DISTORTION This test measures the distortion of the envelope when the DS345 is ampli tude modulating its output specification lt 35 dB at 1 kHz 1 Connect the DS345 s output to the RF spectrum analyzer Set the DS345 to sinewave 1 MHz 10 Vpp Set the modulation to AM sine wave 1 kHz rate 80 depth Turn the modulation on 2 Set the spe
180. status bytes the serial poll byte the standard status byte and the DDS status byte On power on the DS345 may either clear all of its status enable registers or maintain them in the state they were in on power down The action taken is set by the PSC command and allows things such as SRQ on power up Serial Poll Status Byte bit oO name Sweep Done Mod Enable User SRQ DDS MAV ESB RQS MSS No Command usage set when no sweeps are in progress set when modulation is enabled set if the user sends a SRQ from the front panel An unmasked bit in the DDS status register has been set The gpib output queue is non empty An unmasked bit in the standard status byte has been set SRQ Service Request bit There are no unexecuted commands in the input queue The DDS and ESB bits are set whenever any unmasked bit bit with the corresponding bit in the byte enable register set in their respective status registers is set They are not cleared until the condition which set the bit is cleared Thus these bits give a constant summary of the enabled status bits A service request will be generated whenever an unmasked bit in the serial poll register is set Note that service requests are only pro duced when the bit is first set and thus any condition will only produce one service request Accordingly if a service request is desired every time an event occurs the status bit must be cleared between events Standard Event
181. stor Metal Film 1 8W 1 50PPM R 401 4 00130 407 1 00K Resistor Metal Film 1 8W 1 50PPM R 402 4 00031 401 100 Resistor Carbon Film 1 4W 5 R 409 4 00783 407 34 0K Resistor Metal Film 1 8W 1 50PPM R 410 4 00138 407 10 0K Resistor Metal Film 1 8W 1 50PPM R 420 4 00031 401 100 Resistor Carbon Film 1 4W 5 R 421 4 00031 401 100 Resistor Carbon Film 1 4W 5 R 422 4 00138 407 10 0K Resistor Metal Film 1 8W 1 50PPM R 423 4 00218 408 10 00K Resistor Metal Film 1 8W 0 1 25ppm R 426 4 00188 407 4 99K Resistor Metal Film 1 8W 1 50PPM R 428 4 00684 408 100 0K Resistor Metal Film 1 8W 0 1 25ppm R 432 4 00176 407 3 01K Resistor Metal Film 1 8W 1 50PPM R 433 4 00185 407 4 02K Resistor Metal Film 1 8W 1 50PPM R 434 4 00718 407 23 7K Resistor Metal Film 1 8W 1 50PPM R 435 4 00164 407 20 0K Resistor Metal Film 1 8W 1 50PPM R 436 4 00418 407 7 32K Resistor Metal Film 1 8W 1 50PPM R 438 4 00738 407 442 Resistor Metal Film 1 8W 1 50PPM R 439 4 00329 407 402 Resistor Metal Film 1 8W 1 50PPM R 440 4 00414 407 549 Resistor Metal Film 1 8W 1 50PPM R 441 4 00557 407 40 2K Resistor Metal Film 1 8W 1 50PPM R 442 4 00666 407 73 2K Resistor Metal Film 1 8W 1 50PPM R 443 4 00032 401 100K Resistor Carbon Film 1 4W 5 R 444 4 00032 401 100K Resistor Carbon Film 1 4W 5 9 17 EE Component Part List R 445 4 00032 401 100K Resistor Carbon Film 1 4W 5 R 446 4 00239 407
182. stored energy in C205 to operate as the 5 volt logic supply goes away JP500 is the interface connector to the communication board see sheet 5 DISPLAY AND KEYBOARD SHEET 3 OF 7 Input port U302 provides input from the strobed front panel keypad Input port U301 provides input for dip switch SW300 as well as misc input bits for HOST ACKNOWLEDGE TRIGGER ERROR and A D COMPARE The LED strobe lines come from U306 and are buffered by Q301 Q306 8 1 BBS 05345 Circuitry U306 also provides an output for the key click speaker S300 U303 U304 and U305 provide output bits for all of the front panel LEDs RIBBON CABLE TRIGGER AND SYNC SELECT SHEET 4 OF 7 JP401 is the connector for the ribbon cable carrying all of the signals to and from the top PC board Every signal line is alternated with a ground or power line to minimize crosstalk U401 is the trigger multiplexer and selects the DDS trigger source A trigger error is indicated if U211B detects that the unit is already triggered or sweep ing when a trigger occurs U402 and U403 provide drive for the SYNC TRIG BLANK and MARKER outputs JP400 is the connector for the top board power supplies with the exception of the 5 volt logic supply which is carried on JP401 GPIB AND RS232 INTERFACES SHEET 5 OF 7 The field installable interface PCB offers RS232 and GPIB communications that are optically isolated from the DS345 s floating circuitry All connections are ma
183. sum of the data values Thus a total of i 1 32 bit values will be sent When modulation is enabled each modulation point takes N 2 0us to execute where N is the arbitrary modulation rate divider see the AMRT command The MODULATION OUTPUT will output the modulation waveform when modulation is enabled with 0 V corresponding to the minimum frequency and 5 0 V corresponding to the maximum frequency in the modulation pattern EM Programming Commands Arbitrary PM Each arbitrary PM point is a 32 bit integer value This value is the phase shift to be made relative to the current phase The values may range from 180 to 180 The 32 bit value is calculated from the formula value 231 phase shift 180 Negative values are expected in 2 s complement format bit 31 is the sign bit Thus the i data points form a list of i phase shifts to be executed The i data values should be followed by a 32 bit checksum simply the 32 bit sum of the data values Thus a total of i 1 32 bit values will be sent When modulation is enabled each modulation point takes N 0 5us to execute where N is the arbitrary modulation rate divider see the AMRT command The MODULATION OUTPUT will output the modulation waveform when modulation is enabled with O V corresponding to the mini mum phase shift and 5 0 V corresponding to the maximum phase shift in the modulation pattern LDWF i j The LDWF query allows downloading arbitrary waveforms in either point i 0
184. t settings 2 Press AMPL then 5 Vpp Set the amplitude to 5Vpp 3 Press SWEEP MODE UP ARROW twice Set the modulation type to linear sweep 4 Press RATE then 1 0 O Hz Set the sweep rate to 100 Hz The sweep will take 10 ms 1 100Hz Set the scope time base to 1ims div 5 Press START FREQ then 1 0 O kHz Set the sweep start frequency to 100 kHz 1 2 Getting Steriod 6 Press SHIFT STOP F then 1 MHz Set the stop frequency to 1 MHz 7 Press SWEEP ON OFF This starts the sweep The MOD SWP LED will light indicating that the DS345 is sweeping The scope should show the SWEEP output as a OV to 10 V sawtooth wave The sweep starts at 100kKHz when the sawtooth is at O V and moves to 1MHz when the sawtooth is at 10 V The FUNCTION output is the swept sine wave The markers are not yet active 8 Press SHIFT MRK STOP then 9 0 0 kHz Display the stop marker position and set the stop marker to 900 kHz The marker should now be high from the start of the sweep to 900kHz 9V on the sweep sawtooth then the marker should go low 9 Press SHIFT MRK START then 2 0 0 KHz Set the start marker to 200 kHz The marker is now low from the beginning of the sweep until the 200 kHz start marker 2V on the sawtooth The marker stays high until the 900 kHz stop marker The markers allows designating any two frequen cies in the sweep 10 Press SHIFT SPAN MRK This sets the sweep span to the marker
185. tatus when done Status Byte Definitions Serial Poll Status Byte bit name 0 Sweep Done 1 Mod Enable 2 User SRQ 3 DDS 4 MAV 5 ESB 6 RQS 7 No Command usage set when no sweeps in progress set when modulation is enabled set when the user issues a front panel SRQ set when an unmasked bit in DDS status byte is set set when GPIB output queue is non empty set when an unmasked bit in std event status byte is set SRQ bit set when there are no unexecuted commands in input queue Standard Event Status Byte oy RwWNM 0o oo name unused unused Query Error unused Execution Err Command Err URQ PON DDS Status Byte Z v o NO name Trig d Trig Error Ext Clock Clk Error Warmup Test Error Cal Error mem err usage set on output queue overflow set on error in command execution set on command syntax error set on any front panel key press set on power on usage set on burst sweep trigger set on trigger error set when locked to an external clock set when an external clock error occurs set when the DS345 is warmed up set when self test fails set when autocal fails set on power up memory error I OG Introduction This section is designed to familiarize you with the operation of the DS345 Synthesized Function Generator The DS345 is a powerful flexible generator capable of producing both continuous and modulated waveforms of excep tional purity and reso
186. that require a step response The 9th order Cauer provides optimum sine reconstruction The filters are balanced differential filters and are constructed with inductors on common toroidal forms This and the balanced balanced output of the waveform DAC improve the common mode noise rejection of the signal path U600 is a multiplier configured as a frequency doubler which extends the DAC s 15 MHz output up to the 30 MHz final output range The network and quad transistor array U604 converts the current output of the multiplier to a level shifted output to drive the output amplitude control multiplier Op amp U111B serves to correct the output DC levels and the voltage summed at U604B s emitter via R614 nulls the mixer s DC offset which is proportional to the square of the RF amplitude Peaking inductors in series with R607 and R608 provide some gain boost to account for output roll off above 20 MHz SYNC AND GAIN ADJUST SHEET 7 OF 7 Multiplier U702 controls the output signal amplitude before the differential sig nal is sent to the bottom PC board output amplifier via J700 and J701 Po tentiometer P700 feeds a little bit of variable input signal into the multiplier X1 input the X inputs being the DC multiplying term and the Y inputs being the 8 6 ES 0245 circuitry signal inputs to help cancel out the 2f component in the output The network of resistors connected to the multiplier X inputs serves to offset the control voltage so that
187. to voltage and level shifted by op amp U110 to a 5 5 volt range Five multiplexed sampled and held voltages are made avail able from MUX U100 and sample hold buffers U107A D and U111A System A to D conversion is accomplished by successive approximation us ing the system DAC voltage at the output of U110B as the comparison refer ence The voltage to be converted is compared to the DAC output by U102 and the compare result is sent to the system processor on the bottom board One of eight analog voltages to be converted is selected by U103 and pre sented to sample and hold capacitor C113 and buffer U108A U104 generates port strobes to be used on the top PCB CLOCKS SHEET 2 OF 7 The main system clock source is a 40 MHz varactor tuned crystal oscillator The oscillator configuration is a Butler emitter follower consisting of Q203 crystal X200 and tank circuit L204 L205 and C202 C208 and the varactor U201 The emitter follower configuration provides the low impedance of the emitter to drive the crystal and the capacitive tap into the tank circuit pro vides a high impedance at the transistor base The resonant frequency of the oscillator is fixed at the third harmonic of the crystal primarily by L204 L205 and C202 R233 keeps the Q of the tank low enough to avoid spurious oscillation off the crystal resonance The crystal drive amplitude is fixed by an AGC circuit consisting of detector D207 and buffer U205 The current through Q203 i
188. tor remove the mounting screw half way back on the left side of the chassis Next remove the two left hand screws securing the top circuit board This board will hinge open the optional oscillator hinges with the circuit board In the center of the bottom circuit board is a four position DIP switch labelled SW300 Set SW300 switch 2 ON to enable calibration and OFF to disable calibration The DS345 s calibration is controlled by calibration constants calbytes that the firmware uses to adjust the various output parameters These calbytes are stored in the DS345 s RAM Recalibration of the DS345 involves deter mining the values of the calbytes and storing the new values in RAM The calbyte values at the time of the DS345 s production are also stored in ROM and may be recalled at any time Direct access to the DS345 s calbytes is allowed from both the front panel and computer interfaces after calibration is enabled From the front panel press SHIFT CALIBRATE three times to display the calbyte menu line There are two displayed parameters on the left is the calbyte number and on the right is the calbyte value The calbyte number and value may be mod ified with either the keypad or the MODIFY keys To select an item use the SHIFT RIGHT ARROW and SHIFT LEFT ARROW keys The calbyte number may be set between 0 and 509 The calbyte value may be set be tween 32768 and 32767 The complete set of factory calbyte values may be recalled by pr
189. ual The first set of tests test the basic functionality of the DS345 from the front panel The second set of tests actually measure the DS345 s specifications The results of each test may be recorded on the test sheet at the end of this section NECESSARY EQUIPMENT The following equipment is necessary to complete the tests The suggested equipment or its equivalent may be used Instrument Critical Specifications Recommended Model Analog Oscilloscope 350 MHz Bandwidth Tektronix 2465 Time Interval Counter Frequency Range 20 MHz min SRS SR620 Time Interval Accuracy ins min FFT Spectrum Analyzer Frequency Range DC to 100 kHz SRS SR760 Amplitude Accuracy 0 2 dB Distortion lt 75 dB below reference RF Spectrum Analyzer Frequency Range 1 kHz to 100 MHz Anritsu MS2601 HP4195A Amplitude 0 5 dB Distortion and Spurious lt 70 dB DC AC Voltmeter 5 1 2 Digit DC accuracy Fluke 8840A True RMS AC to 100 kHz Thermal Converter Input Impedance 50 Q Ballantine 1395A 3 09 Input Voltage 3 Vrms Frequency DC to 30 MHz Accuracy 0 05dB 10 MHz Frequency Standard Frequency 10 MHz 001 ppm SRS FS700 Phase Noise lt 130 dBc 100Hz 50 Q Terminator 50 Q 0 2 1 Watt HP 11048C Doubly Balanced Mixer Impedance 50 Q Mini Circuits ZAD 3SH Frequency 1 20 MHz 1 MHz Lowpass Filter 50 dB min at f gt 15 MHz TTE Inc Model J85 15 kHz Lowpass Filter 11 0 kQ 0 0015 uF Homemade HMI Performance Tests r FUNCTIONA
190. ure 1 Block diagram Modulation RAM of SRS DDS ASIC Fixed Frequency Reference Phase Phase Waveform Fixed Increment Accumulator RAM Frequency Co Register i 16k points Filter 48 Bits 48 bits pi 2 1 EE introduction ee through the entire waveform RAM changes thus changing the output fre quency Frequency changes now can be accomplished phase continuously in only one clock cycle And the fixed clock eliminates phase jitter and requires only a simple fixed frequency anti aliasing filter at the output The DS345 uses a custom Application Specific Integrated Circuit ASIC to implement the address generation in a single component The frequency res olution is equal to the resolution with which the Phase Increment can be set In the DS345 the phase registers are 48 bits long resulting in an impressive 1 1014 frequency resolution The ASIC also contains a modulation control CPU that operates on the Phase Accumulator Phase Increment and exter nal circuitry to allow digital synthesis and control of waveform modulation The Modulation CPU uses data stored in the Modulation RAM to produce amplitude frequency phase and burst modulation as well as frequency sweeps All modulation parameters such as rate frequency deviation and modulation index are digitally programmed DDS gives the DS345 greater flexibility and power than conventional synthe sizers or arbitrary waveform generators without the drawbacks inherent in PLL designs
191. ust be set to SINGLE BCNT i The BCNT command sets the burst count to i 1 to 30000 The maximum value of i is limited such that the burst time does not exceed 500s that is the burst count waveform period lt 500s The BCNT query returns the cur rent burst count DPTH 7 i The DPTH command sets the AM modulation depth to i percent O to 100 Ifi is negative the modulation is set to double sideband suppressed car rier modulation DSBSC with i modulation The DPTH query returns the current modulation depth FDEV x The FDEV command sets the FM span to x Hertz The maximum value of x is limited so that the frequency is never less than or equal to zero or greater than that allowed for the selected function The FM waveform will be cen tered at the front panel frequency and have a deviation of span 2 The FDEV query returns the current span MDWF i The MDWF command sets the modulation waveform to i The correspon dence of i to waveform is shown in the table below If i is a value not allowed by the current modulation type an error will be generated The MDWF 3 4 EE Programming Commands Il query returns the current modulation waveform Waveform SINGLE SWEEP RAMP TRIANGLE SINE SQUARE ARB NONE The value i 5 ARB may only be set for AM FM and PM The arbitrary waveform must be downloaded via the AMOD query If no waveform has been downloaded and modulation is enabled with the waveform set to ARB
192. vider 3 6 EE Programming Commands Ii The following commands allow downloading arbitrary waveform and modulation patterns The commands have several things in common First the data are sent as multi byte binary not ASCII data and the binary data is followed by a checksum to ensure data integrity The data is sent least significant byte first The checksum is just the sum of the data values sent ignoring carries Second the commands are queries that is after the command is received and processed the DS345 will return the ascii value 1 indicating that it is ready to receive the binary data stream When using these commands the program should wait for return val ue before sending the binary data During the downloading of the binary data there is a 10 second receive data timeout That is if more than 10 seconds elapses between successive data values an error will be gen erated and downloading aborted AMOD i The AMOD query allows downloading arbitrary modulation patterns The modulation type must be set to AM FM or PM i is the number of points to be downloaded and is limited to 10000 AM points 1500 FM points and 4000 PM points To generate an arbitrary modulation follow the following steps 1 Send the query AMOD i where i is the number of points in the waveform 2 Wait until the DS345 returns 1 indicating that it is ready to receive data 3 Send the modulation data discussed below The i data points are sent least signific
193. will round the value to the nearest integer submultiple of 40 MHz Note that the frequency for the standard functions is never rounded Setting the Frequency To set the frequency of any function simply type a new value on the keypad and complete the entry with the appropriate units Hz kHz or MHz The MODIFY keys may be used to increase or decrease the frequency by the cur rent step size Press STEP SIZE key to display and change the step size AMPLITUDE Pressing AMPL displays the amplitude of the output function The amplitude may be set and displayed in units of Vpp Vims and dBm The current units are indicated by the LEDs at the right of the display The amplitude range is limited by the DC offset setting since Vac peak Vacl 5 V If the DC offset is zero the amplitude range for each of the functions is shown below note The rms and dBm values for NOISE are based on the total power in the output bandwidth about 10 MHz at a given peak to peak setting Sine Square Triangle Ramp Noise Arbitrary Arbitrary function amplitude may only be set in units of Vp The output sig nal will briefly go to zero as the output attenuators are switched The units of the amplitude display may be switched between V_ Vims and dBm without changing the actual amplitude by pressing the corresponding units key When the DS345 is switched from one function to another the peak to peak amplitude is held constant If the DC offset is zero th
194. xample if the display is 3 0 Vrms the AMPL query will return 3 0VR If a units indicator is sent with the AMPL query such as AMPL VP the dis played units will be changed to match the units indicator and the amplitude returned in those units ATTL The ATTL command sets the TTL output levels of 5 V peak to peak with a 2 5 V offset That is from OV to 5V FREQ x The FREQ command sets the output frequency to x Hertz The FREQ query returns the current output frequency The frequency is set and re turned with 1uHz resolution If the current waveform is NOISE an error will be generated and the frequency will not be changed This command does not set the sampling frequency for arbitrary waveforms see the FSMP com mand FSMP x The FSMP command sets the arbitrary waveform sampling frequency to x This frequency determines the rate at which each arbitrary waveform point is output That is each point in the waveform is played for a time equal to 1 FSMP The allowed values are 40 MHz N where N is an integer between 1 and 284 1 If x is not an exact divisor of 40 MHz the value will be rounded to the nearest exact frequency The FSMP query returns the current arbitrary waveform sampling frequency FUNC i The FUNC command sets the output function type to i The correspondence of i and function type is shown in the table below If the currently selected frequency is incompatible with the selected function an error will be generat
195. y function generators bypass the need for wave shaping circuitry Usually a PLL is used to create a variable frequency clock that increments an address counter The counter addresses memory locations in waveform RAM and the RAM output is converted by a high speed digital to analog converter DAC to produce an analog waveform The waveform RAM can be filled with any pattern to produce arbitrary functions as well as the usual sine triangle etc The sampling theorem states that as long as the sampling rate is greater than twice the frequency of the waveform being produced with an appropriate filter the desired waveform can be perfectly reproduced Since the frequency of the waveform is adjusted by changing the clock rate the output filter frequency must also be variable Arbitrary generators with a PLL suffer the same phase jitter transient response and resolution problems as synthesizers DDS DDS also works by generating addresses to a waveform RAM to produce data for a DAC However unlike earlier techniques the clock is a fixed fre quency reference Instead of using a counter to generate addresses an ad der is used On each clock cycle the contents of a Phase Increment Register are added to the contents of the Phase Accumulator The Phase Accumula tor output is the address to the waveform RAM see diagram below By changing the Phase Increment the number of clock cycles needed to step Direct Digital Synthesis External Control Fig
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