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Gated Mode - Electrocomponents

1. Calibration All parameters can be calibrated without opening the case i e the generator offers closed box calibration All adjustments are made digitally with calibration constants stored in EEPROM The calibration routine requires only a DVM and a frequency counter and takes no more than a few minutes The crystal in the timebase is pre aged but a further ageing of up to 5ppm can occur in the first year Since the ageing rate decreases exponentially with time it is an advantage to recalibrate after the first 6 month s use Apart from this it is unlikely that any other parameters will need adjustment Calibration should be carried out only after the generator has been operating for at least 30 minutes in normal ambient conditions Equipment Required e 3 digit DVM with 0 25 DC accuracy and 0 5 AC accuracy at 1kHz e Frequency counter capable of measuring 10 O0000MHz The DVM is connected to the MAIN OUT of each channel in turn and the counter to any SYNC OUT Frequency meter accuracy will determine the accuracy of the generator s clock setting and should ideally be 1ppm Calibration Procedure The calibration procedure is accessed by pressing the calibration soft key on the UTILITY screen CALIBRATION SELECTED Are you sure Opassword tests 0 exit continue The software provides for a 4 digit password in the range 0000 to 9999 to be used to access the calibration procedure If the password is le
2. Trigger Out from CH n 1 Burst done Manual Remote Trigger Lock Out routed via External Lock In from SYNC Out BNC if this another master instrument instrument is the master Internal Lock In PHASE LOCKING from this instrument Master clock in out MODULATION In from front panel BNC AMandscm CH n with MOD CH n carrier Internal mod ODSUN CH n with MOD MOD SUM Out MOD SUM Out from CH n 1 0 to 50 dB in 10dB steps MAIN Out 0 to 50 dB CH n in 10dB steps SINGLE CHANNEL BLOCK DIAGRAM Internal Lock In Manual Remote trigger Internal Trigger Gen EXT TRIG In BNC SUM In BNC MODULATION In BNC Hee T i ee a ee l Channel 1 1 0 Channel2 1 0 Channel 3 100 100 100 00 CH1 MOD SUM Out CH2 MOD SUM Out CH3 MOD SUM Out TRIG Out CH1 TRIG Out CH3 TRIG Out CH4 1 0 Channel4 VO INTER CHANNEL BLOCK DIAGRAM 103 Front Panel Diagrams STATUS E LOCAL CI 0 REMOTE e LOD RECALL INTERCH SWEEP WAVESELECT WAVEEDIT STD ARB CREATE MODIFY STORE COPYCH UTILITY a a th bh TTL CMOS TTL CMOS TTL CMOS TTL CMOS SETUP STATUS CO cHi o E C cH2 o LOCAL Co O REMOTE e LCD RECALL INTERCH SWEEP WAVESELECT WAVE EDIT STD ARB CREATE MODIFY STORE COPYCH UTILITY FREQ AMPL OFFSET FILTER MODE SEQUENCE HOLD TRIGOUT
3. blank is being created in the non volatile backup memory the free memory field shows the remaining unused backup memory This menu can be exited either by pressing the cancel soft key which keeps the name but does not allocate the memory space or by pressing the create soft key which builds a blank waveform and directly calls the MODIFY screen to permit waveform editing Create Waveform Copy 42 Pressing the create from copy soft key calls the following menu create wv0l1 Ofrom sine Osize 01024 cancel create 0 The user defined name and waveform size can be entered after pressing the create and size soft keys respectively exactly as described in the previous section The source waveform which is to be copied can be selected by the from soft key repeated presses of the soft key cursor keys or using the rotary control will scroll through the list of all the available waveforms including any other arbitrary waveforms already created The horizontal size of the waveform being copied does not have to be the same as the waveform being created When the waveform is copied by pressing the create key the software compresses or expands the source waveform to create the copy When the source is expanded the copy has additional interpolated points when the source is compressed significant waveform data may be lost particularly from arb waveforms with narrow spikes if the compression ratio is large The m
4. BLOCK COPY execute 0 start 00400 exit stop 01000 undo dest 00000 save Block copy allows a section of the current waveform to be inserted within itself The block to be inserted is defined by the start and stop addresses Change the addresses by pressing the appropriate soft key and making entries from the keyboard or by rotary control The destination address for the start of the section is set by pressing the dest soft key and entering the address The effect of making the block copy can then by previewed by pressing the execute soft key Note that if there are not enough waveform points between the destination address and end of waveform to accommodate the copied section the waveform being copied will simply be truncated The copy can be removed by pressing the undo soft key or by entering a new destination address Block copy edit operates on the version of the waveform in the channel currently selected by the channel SETUP keys the effect of the edit can be seen by selecting the waveform to run on that channel When the block copy is as required it can be saved by pressing the save soft key the action of saving modifies the waveform in the backup memory and then any other copies of the waveform in other channel memories Once saved the original waveform cannot be recovered Pressing exit returns to the EDIT FUNCTIONS screen without change Waveform Amplitude Pressing the wave amplitude soft key calls the AMPLITUDE scree
5. CH3 CH3 CH3 CH3 CH3 CH3 CH3 CH3 CH2 CH3 CH3 CH4 CH4 CH4 CH4 CH4 CH4 CH4 CH4 CH4 CH4 CH4 CH4 CH4 40dB attenuator 10dB attenuator Sum offset SCM level at full scale AM level at full scale DC offset zero DC offset at full scale DC offset at full scale Multiplier zero Multiplier offset Waveform offset Output level at full scale 20dB attenuator 40dB attenuator 10dB attenuator Sum offset SCM level at full scale AM level at full scale DC offset zero DC offset at full scale DC offset at full scale Multiplier zero Multiplier offset Waveform offset Output level at full scale 20dB attenuator 40dB attenuator 10dB attenuator Sum offset SCM level at full scale AM level at full scale Clock calibrate Remote Calibration Calibration of the instrument may be performed over the RS232 or GPIB interface To completely automate the process the multimeter and frequency meter will also need to be remote controlled and the controller will need to run a calibration program unique to this instrument The remote calibration commands allow a simplified version of manual calibration to be performed by issuing commands from the controller The controller must send the CALADJ command repeatedly and read the dmm or frequency meter until the required result for the selected calibration step is achieved The CALSTEP command is then issued to accept the new value and
6. CURSOR MARKER OUTPUT a v amplitude 2V polarity negative cursor width 1 The cursor marker signal is output from the rear panel CURSOR MARKER OUT socket It is used as a marker in sweep mode or as a cursor in arbitrary waveform mode It can be used to modulate the Z axis of an oscilloscope or be displayed on a second scope channel With amplitude selected the cursor marker level can be set between 2 and 14V in 2V steps With polarity selected the polarity canbe set positive or negative With polarity setto positive the cursor marker is a positive going pulse from the OV baseline with polarity setto negative the cursor marker is a negative going pulse from the 2 14V set amplitude level i e negative gives an inverted signal When used as a sweep marker i e Sweep mode selected the width is determined by the time spent at the marker frequency see Sweep Marker in the Sweep Operation section for details When used as a cursor during arbitrary waveform editing i e edit waveform selected on the MODIFY screen the width can be adjusted by repeated presses of the cursor width soft key or by using the rotary control The width is adjustable so that the cursor can still be made visible even with long arbitrary waveforms The width is always an odd number of waveform points increasing in steps of 2 points from 1 to 3 5 7 etc A width setting of 1 corresponds to 1 waveform point width 2 is3points width 3 is5pointsandsoonupto widt
7. whether power has been switched off or not Change the basic generator parameters for the selected channel as described in the Standard Waveform Operation section and switch the output on with the MAIN OUT key the ON lamp will light to show that output is on Display Contrast All parameter settings are displayed on the 20 character x 4 row backlit liquid crystal display LCD The contrast may vary a little with changes of ambient temperature or viewing angle but can be optimised for a particular environment by using the front panel contrast control Insert a small screwdriver or trimmer tool through the adjustment aperture marked LCD and rotate the control for optimum contrast Keyboard Pressing the front panel keys displays screens which list parameters or choices relative to the key pressed Selections are then made using the display soft keys and numeric values are changed using the numeric keys or rotary control see the Principles of Editing section The keys are grouped as follows e WAVE SELECT keys call screens from which all standard or already defined arbitrary waveforms can be selected e WAVE EDIT keys call screens from which arbitrary waveforms can be created and modified e FREQuency AMPLitude OFFSET and MODE keys display screens which permit their respective parameters to be edited either from the numeric keypad or using the rotary control cursor keys e Numeric keys permit direct entry of a value for the parameter cu
8. 160 161 178 179 180 182 184 186 Wave amplitude error must be in the range 0 lt n lt 100 Block dest error must be in the range 0 lt n lt wfm len 4 Sequence count value exceeds the maximum of 32768 Sequence count value cannot be less than 1 Trigger generator maximum period is 200s Trigger generator minimum period is 10us Burst count value exceeds the maximum of 1048575 Burst count value cannot be less than 1 Trig Gate freq too high Max 1MHz Continuous mode set Selected function is illegal in tone mode TONE MODE CANCELLED Selected combination of function and mode is illegal Selected mode is not available when phase lock master or slave Cannot delete arbs while a sequence is running Current setup requires an arb wfm which does not exist Trig gate mode and seq step value cause a trigger conflict Seq step value can t mix edge and level between segments Number of pulses in train must be between 1 and 10 Pulse train base level must be gt 5 0V and lt 5 0V Pulse level must be gt 5 0V and lt 5 0V Pulse number must be between 1 and 10 Sweep frequency values must be 0 001mHz to 16MHz Sweep start freq must be less than stop freq Sweep stop freq must be greater than start freq Sweep time value is out of range 0 03s lt n lt 999s Sweep marker value is out of range 0 001Hz lt n lt 16MHz Not locked This error indicates that a phase locking operation has failed Illegal phase value SUM ratio is not
9. Complete waveform set ups can be stored to or recalled from non volatile RAM using the menus called bythe store and recall soft keys Pressing store or the STORE front panel key calls the store screen Save to store No 1 execute Nine stores numbered 1 to 9 inclusive are available Select the store using the rotary control or direct keyboard entry and press execute to implement the store function Pressing recall or the RECALL front panel key calls the recall screen Recall store No 1 set defaults execute In addition to the user defined stores the factory defaults can be reloaded by pressing the set defaults soft key Note that loading the defaults does not change any arbitrary waveforms the set ups stored in memories 1 to 9 or the RS232 GPIB interface settings Channel Waveform Information Information about each channel s waveform memory can be viewed by pressing the chan wfm info soft key CHANNEL WEM INFO waveforms 1 free mem 65436 exit For each channel selected using the channel SETUP keys the number of waveforms and the free memory on that channel are shown Warnings and Error messages The default setup is for all warning and error messages to be displayed and for a beep to sound with each message This setup can be changed onthe error menu error beep ON error message ON warn beep ON Qwarn message ON Each feature can be turned ON or OFF with alternate pre
10. DC positive ramp negative ramp sin x x pulse pulse train cosine haversine and havercosine Range Resolution Accuracy Temperature Stability Output Level Harmonic Distortion Non harmonic Spurii Square Range Resolution Accuracy Output Level Rise and Fall Times Triangle Range Resolution Accuracy Output Level Linearity Error Ramps and Sin x x Range Resolution Accuracy Output Level Linearity Error Sine Cosine Haversine Havercosine 0 1mHz to 16 MHz 0 1mHz or 7 digits 10 ppm for 1 year Typically lt 1 ppm C 2 5mV to 10Vp p into 50Q lt 0 1 THD to 100kHz lt 65dBc to 20kHz lt 50dBc to 1MHz lt 35dBc to 10MHz lt 30dBc to 16MHz lt 65dBc to 1MHz lt 65dBc 6dB octave 1MHz to 16MHz 1mHz to 16MHz 1mHz 4 digits 1 digit of setting 2 5mV to 10Vp p into 500 lt 25ns 0 1mHz to 100kHz 0 1mHz or 7 digits 10 ppm for 1 year 2 5mV to 10Vp p into 500 lt 0 1 to 30 kHz 0 1mHz to 100kHz 0 1mHz 7 digits 10 ppm for 1 year 2 5mV to 10Vp p into 500 lt 0 1 to 30 kHz Pulse and Pulse Train Output Level 2 5mV to 10Vp p into 500 Rise and Fall Times lt 25ns Period Range 100ns to 100s Resolution 4 digit Accuracy 1 digit of setting Delay Range 99 99s to 99 99s Resolution 0 002 of period or 25ns whichever is greater Width Range 25ns to 99 99s Resolution 0 002 of period or 25ns whichever is greater
11. For example if from the default pulse settings of 100us period 50us width the period is changed to 60us the pulse width actual changes to 30us even though the program width is still 50us to get a 50us width with the period at 60us the width must be re entered as 50us after the period has been changed Period can also be changed from the PULSE PERIOD screen called by pressing the FREQ key with Pulse mode selected PULSE PERIOD 100 0 us freq periode The new setting can be entered either as a period in the way already described or as a frequency by first pressing the freq soft key However changing the period frequency from this screen is slightly different from changing period on the pulse setup screen When changing from this screen the number of points in the waveform is never changed just as with a true arb which means that the shortest period highest frequency that can be set is number of waveform points x25 00ns To achieve faster frequencies up to the specification limit the period must be changed from the pulse set up screen changing the frequency from this screen causes the number of points to be reduced as the period is reduced for periods lt 1 25ms Pulse train Setup Pulse trains are turned on with the pulse train softkey onthe STANDARD WAVEFORMS screen pressing the setup soft key beside pulse train calls the first of the setup screens Enter no of pulses in train 1 10 2 done next gt The number of
12. contains data values ranging from 2048 to 2047 will produce a maximum output which is 100 of the programmed peak to peak amplitude if the maximum range of the data values is only 1024 to 1023 for example the maximum output will only be 50 of the programmed level Arb Waveform Creation and Modification General Principles 40 Creating arb waveforms with the instrument alone consists of two main steps e Creating a new blank waveform or a copy of an existing one and giving it a size and aname e Modifying that waveform using the various editing capabilities to get exactly the waveform required These steps are fully described in the Creating New Waveforms and Modifying Arbitrary Waveforms sections which follow Waveform creation using waveform design software also consists of two steps e Creating the waveform using the software on a PC e Downloading the waveform to the generator via the RS232 or GPIB interface This process is described in Appendix 4 Certain constraints apply to the overall operation of the generator during creation and modification of an arb waveform on the instrument these ensure proper management of the arb waveforms and avoid contentions particularly in multi channel instruments The constraints are mentioned in the individual sections which follow but are summarised here e No arb creation or modification is possible unless all channels are running in continuous mode summing and modulation of c
13. continuous gated setup triggered setup The filled diamond indicates that the selected mode is continuous Gated or Triggered modes are selected by pressing the associated soft key which will make the diamond beside that item filled and the diamond beside continuous hollow This screen also illustrates how an ellipsis three dots following the screen text indicates that a further screen follows when that item is selected In the case of the MODE screen illustrated pressing the setup soft key on the bottom line brings up the TRIGGER SETUP menu note that selecting this item does not change the continuous gated triggered selection Some screen items are marked with a double headed arrow a split diamond when selected to indicate that the item s setting can be changed by further presses of the soft key by pressing either cursor key or by using the rotary control For example pressing FILTER brings up the screen shown below FILTER SETUP mode auto Otype 10MHz eliptic Repeated presses of the mode soft key will toggle the mode between its two possible settings of auto and manual Similarly when type is selected repeated presses of the type soft key or cursor keys or use of the rotary control will step the selection through all possible settings of the filter type In addition to their use in editing items identified by a double headed arrow as described above the CURSOR keys and ROTARY CONTROL operate in two
14. lt TRIG gt lt THLDRST gt or lt MANUAL gt Set the sweep direction to lt UP gt lt DOWN gt lt UPDN gt or lt DNUP gt Set the sweep sync lt ON gt or lt OFF gt Set the sweep spacing to lt LIN gt or lt LOG gt Set the sweep marker to lt nrf gt Hz Set the sweep manual parameters to lt UP gt lt DOWN gt Input Output control OUTPUT lt cpd gt SYNCOUT lt cpd gt TRIGOUT lt cpd gt TRIGIN lt cpd gt TRIGPER lt nrf gt FORCETRG Modulation Commands MOD lt cpd gt MODTYPE lt cpd gt AMDEPTH lt nrf gt SCMLEVEL lt nrf gt SUM lt cpd gt SUMATN lt cpd gt SUMRATIO lt nrf gt Phase Locking Commands REFCLK lt cpd gt ABORT PHASE lt nrf gt LOCKMODE lt cpd gt LOCKSTAT lt cpd gt lt FAST gt lt SLOW gt lt WRAPON gt or lt WRAPOFF gt Set the main output lt ON gt lt OFF gt lt NORMAL gt or lt INVERT gt Set the sync output lt ON gt lt OFF gt lt AUTO gt lt WFMSYNC gt lt POSNMKR gt lt BSTDONE gt lt SEQSYNC gt lt TRIGGER gt lt SWPTRG gt or lt PHASLOC gt Set the trig output to lt AUTO gt lt WFMEND gt lt POSNMKR gt lt SEQSYNC gt or lt BSTDONE gt Set the trig input to lt INT gt lt EXT gt lt MAN gt lt PREV gt lt NEXT gt lt POS gt or lt NEG gt Set the internal trigger generator period to lt nrf gt sec Force a trigger to the selected channel Will function with any trigger source except MANUA
15. lt nrf1 gt lt nrf2 gt lt nrf3 gt ARBOFFSET Load data to an existing arbitrary waveform lt cpd gt must be the name of an existing arbitrary waveform The data consists of two bytes per point with no characters between bytes or points The point data is sent high byte first The data block has a header which consists of the character followed by several ascii coded numeric characters The first if these defines the number of ascii characters to follow and these following characters define the length of the binary data in bytes The data is entered into the arbitrary waveform between the points specified by the ARBEDLMTS command If less data is sent than the number of points between the limits the old data is retained from the point where the new data ends If more data is sent the extra is discarded Due to the binary data block this command cannot be used over the RS232 interface Returns the data from an existing arbitrary waveform lt cpd gt must be the name of an existing arbitrary waveform The data consists of ascii coded values as specified for the ARBDATACSV command The data is sent from the arbitrary waveform between the points specified by the ARBEDLMTS command Returns the data from an existing arbitrary waveform lt cpd gt must be the name of an existing arbitrary waveform The data consists of binary coded values as specified for the ARBDATA command The data is sent from the arbitrary waveform between the point
16. the MAN HOLD key or remote command As with all other sweep control pressing MAN HOLD will halt the sweep on all channels for which sweep has been set on 32 Triggered Burst and Gate General Triggered Burst and Gated modes are selected from the MODE screen called by the MODE key as alternatives to the default continuous mode MODE continuous gated setup triggered setup In Triggered Burst mode a defined number of cycles are generated following each trigger event This mode is edge triggered In gated mode the generator runs whenever the gating signal is true This mode is level sensitive Triggered Burst mode can be controlled by either the Internal Trigger Generator an external trigger input the internal Trigger Out signal from an adjacent channel on a multi channel instrument by the front panel MAN TRIG key or by remote control Gated mode can be controlled by the Internal Trigger Generator or on external trigger input In both modes the start phase i e the starting point on the waveform cycle can be specified Internal Trigger Generator The period of the Internal Trigger Generator is set with the period soft key on the TRIGGER IN setup screen called by the TRIG IN key TRIGGER IN force 0 source internal slope positive period 2 00ms The Internal Trigger Generator divides down a crystal oscillator to produce a 1 1 square wave with a period from 0 01ms 100kHz to 200s 005Hz Generator p
17. 2 and so on through all the pulses in the pulse train In this way all parameters of all pulses are set The pulse train is built when next is pressed on the last screen of the last pulse or if done is pressed on any screen Care must be taken that the set widths and delays of the individual pulses are compatible with each other and the overall pulse train period i e delays must not be such that pulses overlap each other and delays widths must not exceed the pulse train period unpredictable results will occur if these rules are not followed Once the pulse train has been defined the period can be adjusted irrespective of the pulse width and delay settings for the individual pulses because unlike a conventional pulse generator the individual pulse widths and delays are adjusted proportionally to the period as the period is changed Period can also be changed from the PULSE TRN PERIOD screen called by pressing the FREQ key with pulse train mode selected PULSE TRN PERIOD 100 0 us freq period The new setting can be entered either as a period in the way already described or as a frequency by first pressing the freq soft key However changing the period frequency from this screen is slightly different from changing period onthe pulse train setup screen When changing from this screen the number of points in the waveform is never changed just as with a true arb which means that the shortest period highest frequency that can be set
18. 2 CHANNEL STATUS CO RECALL CI LOCAL CoO REMOTE o eLCD VE SELECT WAVE EDIT MAN TRIG 7 8 9 ENTER CE FREQ AMPL STD ARB CREATE MODIFY LJ O O LICI LU MAN HOLD 4 5 OFFSET MODE SEQUENCE SWEEP FILTER UTILITY TRIG IN MODULATION SUM SYNC OUT MAIN OUT SINGLE CHANNEL 104
19. 38 bit accumulator and a clock frequency which is 2 x 10 4 27 4878 MHz this yields a frequency resolution of 0 1 mHz Only the 12 most significant bits of the phase accumulator are used to address the RAM Ata waveform frequency of Fcik 4096 6 7kHz the natural frequency the RAM address increments at every clock At all frequencies below this i e at smaller phase increments one or more addresses are output for more than one clock period because the phase increment is not big enough to step the address at every clock Similarly at frequencies above the natural frequency the larger phase increment causes some addresses to be skipped giving the effect of the stored waveform being sampled different points will be sampled on successive cycles of the waveform Standard Waveform Operation This sections deals with the use of the instrument as a standard function generator i e generating sine square triangle dc ramp haversine cosine havercosine and sinx x waveforms All but squarewave are generated by DDS which gives 7 digit frequency precision squarewave is generated by Clock Synthesis which results in only 4 digit frequency resolution Refer to Principles of Operation in the previous section for a fuller explanation of the differences involved The STANDARD WAVEFORMS screen also includes arbitrary and sequence for simplicity of switching between these and standard waveforms they do however have their own screens accessed by pres
20. INTERFACES Full remote control facilities are available through the RS232 or GPIB interfaces RS232 IEEE 488 GENERAL Display Data Entry Stored Settings Size Weight Power Operating Range Storage Range Environmental Options Safety EMC Variable Baud rate 9600 Baud maximum 9 pin D connector Conforms with IEEE488 1 and IEEE488 2 20 character x 4 row alphanumeric LCD Keyboard selection of mode waveform etc value entry direct by numeric keys or by rotary control Up to 9 complete instrument set ups may be stored and recalled from battery backed memory Up to 100 arbitrary waveforms can also be stored independent of the instrument settings 3U 130mm height 350mm width 2 and 4 channels 212mm 72 rack single channel 335mm long 7 2 kg 16 Ib 2 and 4 channels 4 1kg 9lb 1 channel 100V 110V 120V 220V 240V AC 10 50 60HZ adjustable internally 100VA max for 4 channels 75VA max for 2 channels 40VA max for 1 channel Installation Category Il 5 C to 40 C 20 80 RH 20 C to 60 C Indoor use at altitudes up to 2000m Pollution Degree 2 19 inch rack mounting kit Complies with EN61010 1 Complies with EN61326 11 12 Safety This generator is a Safety Class instrument according to IEC classification and has been designed to meet the requirements of EN61010 1 Safety Requirements for Electrical Equipment for Measurement Control and Laboratory
21. Note that the pulse width and absolute value of the delay may not exceed the pulse period at any time Pulse trains of up to 10 pulses may be specified each pulse having independently defined width delay and level The baseline voltage is separately defined and the sequence repetition rate is set by the pulse train period Arbitrary Up to 100 user defined waveforms may be stored in the 256K point non volatile RAM Waveforms can be defined by front panel editing controls or by downloading of waveform data via RS232 or GPIB Waveform Memory Size 64k points per channel Maximum waveform size is 64k points minimum waveform size is 4 points Vertical Resolution 12 bits Sample Clock Range 100mHz to 40MHz Resolution 4 digits Accuracy 1 digit of setting Sequence Up to 16 waveforms may be linked Each waveform can have a loop count of up to 32 768 A sequence of waveforms can be looped up to 1 048 575 times or run continuously Output Filter Selectable between 16MHz Elliptic 10MHz Elliptic 10MHz Bessel or none OPERATING MODES Triggered Burst Each active edge of the trigger signal will produce one burst of the waveform Carrier Waveforms Maximum Carrier Frequency Number of Cycles Trigger Repetition Rate Trigger Signal Source Trigger Start Stop Phase Gated All standard and arbitrary The smaller of 1MHz or the maximum for the selected waveform 40Msamples s for ARB and Sequence 1 to 1 048 575 0 005
22. THIS INSTRUMENT MUST BE EARTHED Any interruption of the mains earth conductor inside or outside the instrument will make the instrument dangerous Intentional interruption is prohibited The protective action must not be negated by the use of an extension cord without a protective conductor Mounting This instrument is suitable both for bench use and rack mounting It is delivered with feet for bench mounting The front feet include a tilt mechanism for optimal panel angle A rack kit for mounting in a 19 rack is available from the Manufacturers or their overseas agents 15 Connections Front Panel Connections MAIN OUT 1 per channel This is the 50Q output from the channel s main generator It will provide up to 20V peak to peak e m f which will yield 10V peak to peak into a matched 509 load It can tolerate a short circuit for 60 seconds Do not apply external voltages to these outputs SYNC OUT 1 per channel This is a TTL CMOS level output which may be set to any of the following signals from the SYNC OUT screen waveform sync position marker Burst done Sequence sync Trigger Sweep sync Phase lock A sync marker phase coincident with the MAIN OUT waveform of that channel For standard waveforms sine cosine haversines square triangle sinx x and ramp the sync marker is a squarewave with a 1 1 duty cycle with the rising edge at the 0 phase point and the falling edge at the 180 phase po
23. Use It is an Installation Category II instrument intended for operation from a normal single phase supply This instrument has been tested in accordance with EN61010 1 and has been supplied in a safe condition This instruction manual contains some information and warnings which have to be followed by the user to ensure safe operation and to retain the instrument in a safe condition This instrument has been designed for indoor use in a Pollution Degree 2 environment in the temperature range 5 C to 40 C 20 80 RH non condensing It may occasionally be subjected to temperatures between 5 and 10 C without degradation of its safety Do not operate while condensation is present Use of this instrument in a manner not specified by these instructions may impair the safety protection provided Do not operate the instrument outside its rated supply voltages or environmental range WARNING THIS INSTRUMENT MUST BE EARTHED Any interruption of the mains earth conductor inside or outside the instrument will make the instrument dangerous Intentional interruption is prohibited The protective action must not be negated by the use of an extension cord without a protective conductor When the instrument is connected to its supply terminals may be live and opening the covers or removal of parts except those to which access can be gained by hand is likely to expose live parts The apparatus shall be disconnected from all voltage sources before it is o
24. and Gated modes can be operated from the previous or next channel from the internal Trigger Generator 0 005Hz to 100kHz from an external source dc to 1MHz or by a key press or remote command Any number of channels can be phase locked with user defined phase angle This can be used to generate multi phase waveforms or locked waveforms of different frequencies The signals from the REF IN OUT socket and the SYNC OUT socket can be used to phase lock two instruments where more than 4 channels are required The generator parameters are clearly displayed on a backlit LCD with 4 rows of 20 characters Soft keys and sub menus are used to guide the user through even the most complex functions All parameters can be entered directly from the numeric keypad Alternatively most parameters can be incremented or decremented using the rotary control This system combines quick and easy numeric data entry with quasi analogue adjustment when required The generator has RS232 and GPIB interfaces as standard which can be used for remote control of all of the instrument functions or for the down loading of arbitrary waveforms As well as operating in conventional RS232 mode the serial interface can also be used in addressable mode whereby up to 32 instruments can be linked to a single PC serial port Specifications Specifications apply at 18 28 C after 30 minutes warm up at maximum output into 50Q WAVEFORMS Standard Waveforms Sine square triangle
25. be displayed and for a beep to sound with each message This set up can be changed on the error menu on the UTILITY screen The error menu is shown below Qerror beep ON Qerror message ON warn beep ON warn message ON Each feature can be turned ON and OFF with alternate presses of the associated soft key the factory default is for all features to be ON If the setting is changed and is required for future use it should be saved by changing the POWER ON SETTING onthe power on menu of the UTILITY screen to restore last setup SYNC Output SYNC OUT is a multifunction CMOS TTL level output that can be automatically or manually set to be any of the following e waveform sync A square wave with 50 duty cycle at the main waveform frequency or a pulse coincident with the first few points of an arbitrary waveform Can be selected for all waveforms e position marker Can be selected for arbitrary waveforms only Any point s on the main waveform may have associated marker bit s set high or low When the MAIN OUT waveform is a standard waveform position marker is not available and this choice on the list automatically becomes phase zero if selected phase zero produces a narrow 1 clock pulse at the start of each standard waveform cycle e burst done Produces a pulse coincident with the last cycle of the burst e sequence sync Produces a pulse coincident with the end of a waveform sequence e trigger Selects the curren
26. count of up to 32768 and the whole sequence can run continuously or be looped up to 1048575 times using the Triggered Burst mode Pressing the SEQUENCE key calls the initial SEQUENCE screen SEQUENCE segs 1 sequence setup stop run A previously defined sequence can be run and stopped from this screen using the run and stop soft keys sequence can also be switched on from the STANDARD WAVEFORMS screen with the sequence soft key The segs field shows the number of segments in the sequence there is always at least 1 segment Sequence Set up Pressing the sequence setup soft keyonthe SEQUENCE screen orthe setup soft key next to sequence onthe STANDARD WAVEFORMS screen calls the sequence set up screen seg 2 ewfm wv03 step on count cnt 00001 done 0 Repeated presses of the seg soft key steps the display through the set ups of each of the 16 segments of the sequence With the exception of segment 1 which is always on and therefore has no on off soft key the 16 segment set ups are identical in format When segment 1 is displayed the segs field shows the total number of segments in the current sequence The segment to be set up is selected with the seg soft key the 16 segments can be selected in sequence with repeated presses of the soft key or by using the rotary control Once the segment to be edited has been set the waveform for that segment is selected with the wfm waveform soft key the list of all arb
27. from the keyboard or by using the rotary control Pressing the next soft key calls the pulse width screen Enter pulse width program 50 00 us actual 50 00 us Yvexit next gt The width can be entered directly from the keyboard or by using the rotary control Any value in the range 25 00ns to 99 99s can be programmed but the actual value may differ because of the considerations discussed below for this reason the actual pulse width is shown in brackets below the program width Pressing the next soft key calls the pulse delay screen Enter pulse delay program 0 000 ns actual 0 000 ns exit done 0 This is very similar to the pulse width screen and again the actual delay is shown below the program delay The delay value that can be entered must be in the range pulse period 1 point positive values delay the pulse output with respect to waveform sync from SYNC OUT negative values cause the pulse to be output before the waveform sync Pressing the done soft key on this screen returns the display to the STANDARD WAVEFORMS screen The means by which pulse period is set up in the hardware requires an understanding because it affects the setting resolution of both pulse width and delay Pulse is actually a particular form of arbitrary waveform made up of between 4 and 50 000 points each point has a minimum time of 25 00ns corresponding to the fastest clock frequency of 40MHz At short pulse periods i e only a few
28. list of all arbitrary waveforms in backup memory each will return a name and length in the following form lt cpd gt lt nr1 gt The list will end with lt rmt gt Arbitrary Waveform Create and Delete NOTE Care should be take to ensure that all channels in the instrument are running in CONTINUOUS mode before using commands from this section Failure to observe this restriction may give unexpected results ARBDELETE lt cpd gt ARBCLR lt cpd gt ARBCREATE lt cpd gt lt nrf gt Delete the arbitrary waveform lt cpd gt from backup memory Delete the arb lt cpd gt from channel memory The backup memory is not changed Create a new blank arbitrary waveform with name lt cpd gt and length lt nrf gt points 85 ARBDEFCSV lt cpd gt lt nrf gt lt csv ascii data gt ARBDEF lt cpd gt lt nrf gt lt bin data block gt Define a new or existing arbitrary waveform with name lt cpd gt and length lt nrf gt and load with the data in lt csv ascii data gt If the arbitrary waveform does not exist it will be created If it does exist the length will be checked against that specified and a warning will be issued if they are different The edit limits will be set to the extremes of the waveform The data consists of ascii coded values in the range 2048 to 2047 for each point The values are separated by a comma character and the data ends with lt pmt gt If less data is sent than the number of points in the wa
29. log and marker position are all accessed from this screen using the appropriate soft key In addition the control screen for manual sweep i e sweeping using the rotary control or cursor keys is selected from this screen and Sweep Mode itself is turned on and off with alternate presses of the on off soft key sweep can also be turned on by the sweep soft key on the MODE screen In multi channel instruments two or more channels can be swept at once using the same sweep parameters The channels to be swept are set on or off by selecting them in turn with the appropriate SETUP key and then using the on off _ soft key of the SWEEP SETUP screen On all the following menus pressing the done _ soft key returns the display to this SWEEP SETUP screen Sweep Range Pressing the range soft key calls the SWEEP RANGE screen SWEEP RANGE start 100 0 kHz stop 10 00 MHz Ocentr span done 0 The maximum sweep range for all waveforms is 1mHz to 16MHz including triangle ramp and squarewave which have different limits in unswept operation Sweep range can be defined by start and stop frequencies or in terms of a centre frequency and span Start and Stop soft keys permit the two end points of the sweep to be set directly from the keyboard or by using the rotary control the start frequency must be lower than the stop frequency but see Sweep Type for selecting sweep direction Pressing the centr span soft key changes the screen to permit entry
30. lt nrf2 gt by the factor lt nfr3 gt Move the data in arbitrary waveform lt cpd gt from start address 87 lt cpd gt lt nrf1 gt lt nrf2 gt lt nrf3 gt ARBINVERT lt cpd gt lt nrf1 gt lt nrf2 gt ARBLEN lt cpd gt POSNMKRCLR lt cpd gt POSNMKRSET lt cpd gt lt nrf gt POSNMKRRES lt cpd gt lt nrf gt POSNMKRPAT lt cpd1 gt lt nrf1 gt lt nrfi2 gt lt cpd2 gt Waveform Sequence Control SEQWFM lt nrf gt lt cpd gt SEQSTEP lt nrf gt lt cpd gt SEQCNT lt nrf1 gt lt nrf2 gt SEQSEG lt nrf gt lt cpd gt Mode Commands MODE lt cpd gt BSTCNT lt nrf gt PHASE lt nrf gt TONEEND lt nrf gt TONEFREQ lt nrf1 gt lt nrf2 gt lt nrf3 gt SWPSTARTFRQ lt nrf gt SWPSTOPFRQ lt nrf gt SWPCENTFRQ lt nrf gt SWPSPAN lt nrf gt SWPTIME lt nrf gt SWPTYPE lt cpd gt SWPDIRN lt cpd gt SWPSYNC lt cpd gt SWPSPACING lt cpd gt SWPMKR lt nrf gt SWPMANUAL lt cpd gt 88 lt nrf1 gt to stop address lt nrf2 gt by the offset lt nrf3 gt Invert arbitrary waveform lt cpd gt between start address lt nrf1 gt and stop address lt nrf2 gt Returns the length in points of the arbitrary waveform lt cpd gt If the waveform does not exist the return value will be 0 Clear all position markers from arbitrary waveform lt cpd gt Set the position marker at address lt nrf gt in arbitrary waveform lt cpd gt to 1 high Clear the position marker at addr
31. next at the waveform zero crossing point immediately after the trigger signal whereas in gated mode there can be an off period between successive frequencies whilst the gate signal is not true With type setto fsk the frequency changes instantaneously and phase continuously at each occurrence of the signal edge specified in the source and slope fields on the TRIGGER IN screen without completing the current waveform cycle this is true FSK Frequency Shift Keying tone switching The following diagrams demonstrate the differences between trigger gate and FSK tone switching for a list of 2 frequencies switched by a square wave positive slope specified on TRIGGER IN setup The maximum recommended tone frequencies and trigger gate switching frequencies for the three modes are as follows GATE Maximum tone frequency 50kHz maximum switching frequency lt lowest tone frequency TRIGGER Maximum tone frequency 50kHz maximum switching frequency 1MHz FSK Maximum tone frequency 1MHz maximum switching frequency 1MHz l l l l l GATE TRIG FSK TRIGGER WAVEFORM Tone Waveform Types Tone Switching Source The signal which controls the frequency switching is that set by the source soft key on the TRIGGER IN setup screen The slope field on the same screen sets the active polarity of that signal when setto positive the rising edge of the trigger signal is active or the high level of the gating signal is true and the re
32. other calibration commands will be recognised Finish calibration save the new values and exit calibration mode Finish calibration do not save the new values and exit calibration mode lt nrf gt represents the calibration password The password is only required with CALIBRATION START and then only if a non zero password has been set from the instrument s keyboard The password will be ignored and will give no errors at all other times It is not possible to set or change the password using remote commands Adjust the selected calibration value by lt nrf gt The value must be in the range 100 to 100 Once an adjustment has been completed and the new value is as required the CALSTEP command must be issued for the new value to be accepted Step to the next calibration point For general information on remote operation and remote command formats refer to the following sections 73 Remote Operation The instrument can be remotely controlled via its RS232 or GPIB interfaces When using RS232 it can either be the only instrument connected to the controller or it can be part of an addressable RS232 system which permits up to 32 instruments to be addressed from one RS232 port Some of the following sections are general and apply to all 3 modes single instrument RS232 addressable RS232 and GPIB others are clearly only relevant to a particular interface or mode It is only necessary to read the general sections plus those
33. pon bit set 0 0 0 0 t Registers marked thus are specific to the GPIB section of the instrument and are of limited use in an RS232 environment The instrument will be in local state with the keyboard active The instrument parameters at power on are determined on the POWER ON SETTING screen accessed from the UTILITY menu If restore last setup or recall store no nn has been set and a defined state is required by the controller at start up then the command RST should be used to load the system defaults If for any reason an error is detected at power up in the non volatile ram a warning will be issued and all settings will be returned to their default states as for a RST command Remote Commands RS232 Remote Command Formats Serial input to the instrument is buffered in a 256 byte input queue which is filled under interrupt in a manner transparent to all other instrument operations The instrument will send XOFF when approximately 200 characters are in the queue XON will be sent when approximately 100 free spaces become available in the queue after XOFF was sent This queue contains raw un parsed data which is taken by the parser as required Commands and queries are executed in order and the parser will not start a new command until any previous command or query is complete In non addressable RS232 mode responses to commands or queries are sent immediately there is no output queue In addressable mode the r
34. rmt gt Returns the value in the Standard Event Status Register in lt nr1 gt numeric format The register is then cleared The syntax of the response is lt nr1 gt lt rmt gt Returns the instrument identification The exact response is determined by the instrument configuration and is of the form lt NAME gt lt model gt 0 lt version gt lt rmt gt where lt NAME gt is the manufacturer s name lt MODEL gt defines the type of instrument and lt VERSION gt is the revision level of the software installed Returns ist local message as defined by IEEE Std 488 2 The syntax of the response if 0 lt rmt gt if the local message false or 1 lt rmt gt if the local message is true Sets the Operation Complete bit bit 0 in the Standard Event Status Register This will happen immediately the command is executed because of the sequential nature of all operations Query operation complete status The syntax of the response is 1 lt rmt gt The response will be available immediately the command is executed because of the sequential nature of all operations Set the Parallel Poll Enable Register to the value lt nrf gt Returns the value in the Parallel Poll Enable Register in lt nr1 gt numeric format The syntax of the response if lt nr1 gt lt rmt gt Set the Service Request Enable Register to lt nrf gt If the value of lt nrf gt Returns the value of the Service Request Enable Register in lt nr1 gt numeric format The S
35. seconds Listen mode will be cancelled by any of the following interface control codes being received 12H Listen Address followed by an address not belonging to this instrument 14H Talk Address for any instrument 03H Universal Unaddress control code 04H Lock Non Addressable mode control code 18H Universal Device Clear Before a response can be read from an instrument it must be addressed to talk by sending the Talk Address control code 14H followed by a single character which has the lower 5 bits corresponding to the unique address of the required instrument as for the listen address control code above Once addressed to talk the instrument will send the response message it has available if any and then exit the talk addressed state Only one response message will be sent each time the instrument is addressed to talk Talk mode will be cancelled by any of the following interface control codes being received 12H Listen Address for any instrument 14H Talk Address followed by an address not belonging to this instrument 03H Universal Unaddress control code 04H Lock Non Addressable mode control code 18H Universal Device Clear Talk mode will also be cancelled when the instrument has completed sending a response message or has nothing to say The interface code OAH LF is the universal command and response terminator it must be the last code sent in all commands and will be the last code sent in all
36. shown in the ratio field is CH x amplitude CH x 1 amplitude Adjusting the ratio value directly changes the amplitude of the Sum input signal i e CH x never the channel s output amplitude When a value is entered into the ratio field it is initially accepted as entered but may then change slightly to reflect the actual ratio achieved with the nearest Sum input amplitude that could be set for the given channel output amplitude Warnings are given when either a ratio Sum input or output amplitude change is attempted which would cause the channel output to be driven into clipping In general it is recommended that the amplitude of the Sum input is smaller than the channel amplitude i e the ratio is lt 1 most ratio values lt 1 can then be set down to very small signal levels If the Sum input is greater than the channel amplitude there will be combinations when the ratio can be set to a little more than 1 Note that the software will always accept an entry make the calculation and if the combination is not possible return the instrument to the original setting The amplitude of the channel being used for the internal Sum signal can still be adjusted on its own Amplitude set up screen its status screen shows the message x to indicate that it is being used as a source for channel x Internal sum cannot be used with internal modulation 61 Inter Channel Synchronisation Two or more channels can be synchronised together an
37. temporary degradation or loss of function or performance which is self recovering Performance criterion C During test temporary degradation or loss of function or performance which requires operator intervention or system reset occurs Note To achieve Performance B it is necessary to set the instrument such that power down settings are restored at power up set the POWER ON SETTING to restore last setup on the Utility menu Cautions To ensure continued compliance with the EMC directive the following precautions should be observed a connect the generator to other equipment using only high quality double screened cables b after opening the case for any reason ensure that all signal and ground connections are remade correctly before replacing the cover Always ensure all case screws are correctly refitted and tightened c In the event of part replacement becoming necessary only use components of an identical type see the Service Manual 13 Installation Mains Operating Voltage Check that the instrument operating voltage marked on the rear panel is suitable for the local supply Should it be necessary to change the operating voltage proceed as follows 1 Disconnect the instrument from all voltage sources 2 Remove the screws which retain the top cover and lift off the cover 3 Change the transformer connections following the appropriate diagrams below 4 Refit the cover and the secure with the s
38. the stop frequency to the start frequency but is not synchronised to the software generated trigger signal In triggered mode the generator holds the output at the start frequency until it recognises a trigger When triggered the frequency sweeps to the stop frequency resets and awaits the next trigger If syne if set to on the frequency resets to zero frequency i e no waveform and starts a new sweep at the first point of the waveform when the next trigger is recognised If syne is setto off the waveform resets to the start frequency and runs at that frequency until the next trigger initiates a new sweep In trig d hold reset mode the generator holds the output at the start frequency until it recognises a trigger when triggered the frequency sweeps to the stop frequency and holds At the next trigger the output is reset to the start frequency where it is held until the next sweep is initiated by a further trigger If syne is setto off the output operates exactly as described above if syne is setto on the frequency actual goes to zero at the start and begins each new sweep at the first point of the waveform For both triggered and trig d hold reset modes the TRIG IN input is automatically set to external The trigger source can be an external signal applied to TRIG IN positive edge triggers pressing the MAN TRIG key on the front panel or a remote command In manual mode the whole sweep process is controlled from the MANUAL SWEEP scr
39. wave invert soft key calls the INVERT screen INVERT wv02 start adrs 00512 stop adrs 00750 exit invert gt The waveform can be inverted on a section of the waveform defined by the start and stop addresses Set the addresses by pressing the appropriate soft key and making entries directly from the keyboard or by rotary control The data values over the specified section of the waveform are inverted about 0000 each time the invert soft key is pressed Press exit to return tothe EDIT FUNCTIONS screen 47 Position Markers Pressing the position markers soft key calls the POSITION MARKER EDIT screen POSITION MARKER EDIT Vadrs 00000 lt 0 gt 0 Opatterns exit clear allo Position markers are output from SYNC OUT when the source src is setto pos n marker onthe SYNC OUTPUT SETUP screen Position markers can be set at any or all of the addresses of a waveform either individually using the adrs address soft key or as a pattern using the patterns menu A marker can be set directly at an address by pressing the adrs soft key followed by a keyboard entry pressing the right hand soft key onthe adrs line then toggles the marker setting between lt 1 gt and lt 0 gt as shown in the arrowed brackets The address can be changed by incrementing with the adrs_ key by using the rotary control or by further keyboard entries marker settings are changed at each new address with the right hand soft key Marke
40. 0 when false in bit position 1 in response to a parallel poll operation send the following commands PRE 64 lt pmt gt then PPC followed by 69H PPE The parallel poll response from the generator will then be OOH if RQS is 0 and 01H if RQS is 1 During parallel poll response the DIO interface lines are resistively terminated passive termination This allows multiple devices to share the same response bit position in either wired AND or wired OR configuration see IEEE 488 1 for more information Status Reporting This section describes the complete status model of the instrument Note that some registers are specific to the GPIB section of the instrument and are of limited use in an RS232 environment Standard Event Status and Standard Event Status Enable Registers These two registers are implemented as required by the IEEE std 488 2 Any bits set in the Standard Event Status Register which correspond to bits set in the Standard Event Status Enable Register will cause the ESB bit to be set in the Status Byte Register The Standard Event Status Register is read and cleared by the ESR command The Standard Event Status Enable register is set by the ESE lt nrf gt command and read by the ESE command Bit 7 Power On Set when power is first applied to the instrument Bit 6 Not used Bit 5 Command Error Set when a syntax type error is detected in a command from the bus The parser is reset and parsin
41. AM is selected the screen has an additional soft key labelled depth selecting this key permits the modulation depth to be set directly from the keyboard or by the rotary control Warnings are given when either a modulation depth or output amplitude change has caused clipping the new setting is accepted but it must either be changed back or the other parameter must also be changed to avoid the contention When scM is selected the screen has an additional soft key labelled level selecting this key permits the peak carrier output level to be set directly from the keyboard or by the rotary control The maximum output level that can be set is 10Vpp When internal SCM is selected for a channel both the amplitude control of that channel and the previous channel used as the modulation source are disabled The AMPLITUDE setup screen of the channel being modulated shows the message fixed by SCM The AMPLITUDE screen of the previous channel shows the message Set by CHx mod and its status screen shows the message x to indicate that it is being used as a source for channel x Internal modulation cannot be used with internal or external Sum 59 Sum Introduction Both internal and external Sum can be selected summing can be used to add noise to a waveform for example or to add two signals for DTMF Dual Tone Multiple Frequency testing External Sum can be applied to any or all channels Internal sum uses the previous channel as the
42. Arbitrary Waveforms At switch on assuming factory default settings any arbitrary waveforms already created will only be stored in the non volatile back up memory To run an arbitrary waveform it is necessary to select it from the list in back up memory Press the ARB key to see the list on the ARBS screen of all arbitrary waveforms held in back up memory ARBS backup mem Owv00 01024 Owv01 03782 Owv02 00500 The rotary knob or cursor keys can be used to scroll the full list backwards and forwards through the display With the appropriate channel selected using its SETUP key press the soft key beside the required waveform to load it into that channel s memory Many waveforms can be loaded into and held in the channel s memory in this way up to the 64k point limit the last one selected will be the one currently output on that channel Once an arb waveform has been loaded into a channel it can also be selected to run from the STANDARD WAVEFORMS screen accessed by pressing the STD key by pressing the arb soft key if more than one arb waveform is held in the channel s memory the last one selected will be the one that is output The complete list of waveforms held in a channel s memory can be viewed by pressing the top right soft key on the ARBS screen this causes the channel memory to be displayed instead of the backup memory e g ARBS chan mem owv01 03872 dwv03 00128 If the power on setting has been setto resto
43. ED BY AMPLITUDE willbe shown temporarily on the screen but the setting will be accepted in this case the actual attenuated offset will be shown in brackets below the set value 2 With the output level set to 10V pk pk increasing the DC offset beyond 5V will cause the message OFFSET SUM LEVEL MAY CAUSE CLIPPING The offset change will be accepted producing a clipped waveform and the user may then choose to change the output level or the offset to produce a signal which is not clipped clip will show in the display beside AMPLITUDE or DC OFFSET while the clipped condition exists ERROR messages are shown when an illegal setting is attempted most generally a number outside the range of values permitted In this case the entry is rejected and the parameter setting is left unchanged Examples are 1 Entering a frequency of 1MHz for a triangle waveform The error message Frequency out of range for the selected waveform is shown 2 Entering an amplitude of 25Vpp The error message Maximum output level exceeded is shown 3 Entering a DC offset of 20V The error message Maximum DC offset exceeded is shown The messages are shown on the display for approximately two seconds The last two messages can be viewed again by pressing the last error soft key on the UTILITY screen see System Operations section Each message has a number and the full list appears in Appendix 1 The default set up is for all warning and error messages to
44. F mains supply ON oHe alternating current EMC This instrument has been designed to meet the requirements of the EMC Directive 89 336 EEC Compliance was demonstrated by meeting the test limits of the following standards Emissions EN61326 1998 EMC product standard for Electrical Equipment for Measurement Control and Laboratory Use Test limits used were a Radiated Class B b Conducted Class B c Harmonics EN61000 3 2 2000 Class A the instrument is Class A by product category Immunity EN61326 1998 EMC product standard for Electrical Equipment for Measurement Control and Laboratory Use Test methods limits and performance achieved were a EN61000 4 2 1995 Electrostatic Discharge 4kV air 4kV contact Performance A b EN61000 4 3 1997 Electromagnetic Field 3V m 80 AM at 1kHz Performance A c EN61000 4 11 1994 Voltage Interrupt 1 cycle 100 Performance B d EN61000 4 4 1995 Fast Transient 1kV peak AC line 0 5kV peak signal lines and RS232 GPIB ports Performance A e EN61000 4 5 1995 Surge 0 5kV line to line 1kV line to ground Performance A f EN61000 4 6 1996 Conducted RF 3V 80 AM at 1kHz AC line only signal connections lt 3m not tested Performance A According to EN61326 the definitions of performance criteria are Performance criterion A During test normal performance within the specification limits Performance criterion B During test
45. GS Saves the complete instrument set up in the store number lt nrf gt Valid store numbers are 1 9 This command is the same as pressing the MAN SYNC key Its effect will depend on the context in which it is asserted The interface command Group Execute Trigger GET will perform the same action as TRG Copy the parameters from the current setup chan to channel lt nrf gt Set hold mode lt ON gt lt OFF gt lt ENAB gt or lt DISAB gt The ON or OFF forms are the same as pressing the HOLD key The ENAB and DISAB forms are channel specific and enable or disable the action of the HOLD key or HOLD input Set the output filter to lt AUTO gt lt EL10 gt lt EL16 gt lt BESS or lt NONE gt Set beep mode to lt ON gt lt OFF gt lt WARN gt or lt ERROR gt Sound one beep Returns the instrument to local operation and unlocks the keyboard Will not function if LLO is in force Refer to Calibration section for remote calibration commands 91 CLS ESE lt nrf gt ESE ESR IDN ST LRN OPC OPC PRE lt nrf gt PRE RCL lt nrf gt RST SAV SRE lt nrf gt SRE STB TRG TST WAI ABORT AMDEPTH lt nrf gt AMPL lt nrf gt AMPUNIT lt cpd gt ARB lt cpd gt ARBAMPL lt cpd gt lt nrf1 gt lt nrf2 gt lt nrf3 gt ARBCLR lt cpd gt ARBCOPY lt cpd gt lt nrf1 gt lt nrf2 gt lt nrf3 gt ARBCREATE lt cpd gt lt nrf gt ARBDATA lt cp
46. Hz sample waveform freq period Frequency can be set in terms of frequency or period as before by pressing the freq or period soft key respectively Note that the frequency and period resolution in arbitrary mode is only 4 digits because Clock Synthesis generation is used see Principles of Operation section Additionally for arbitrary waveforms frequency period can be set in terms of the sample clock frequency by pressing the sample soft key or in terms of the waveform frequency by pressing the waveform soft key The relationship between them is waveform frequency sample frequency waveform size Frequency period entries are made direct from the keyboard or by using the rotary control in the usual way Pressing the FREQuency key with Sequence selected calls the SEQ CLOCK FREQUENCY screen SEQ CLOCK FREQUENCY 40 00 MHz freq period Frequency period can now only be set in terms of the clock frequency Frequency period entries are made direct from the keyboard or by using the rotary control in the usual way Amplitude Pressing the AMPLitude key with an arbitrary waveform selected calls the AMPLITUDE screen AMPLITUDE 20 0 Vpp Vpp load hiZ This differs from the AMPLITUDE screen for standard waveforms in that amplitude can now only be entered in volts peak to peak Note that the peak to peak amplitude set will only actually be output if the arbitrary waveform has addresses with values which rea
47. Hz to 100kKHz internal dc to 1MHz external Internal from keyboard previous channel next channel or trigger generator External from TRIG IN or remote interface 360 settable with 0 1 resolution subject to waveform frequency and type Waveform will run while the Gate signal is true and stop while false Carrier Waveforms Maximum Carrier Frequency Trigger Repetition Rate Gate Signal Source Gate Start Stop Phase Sweep All standard and arbitrary The smaller of 1MHz or the maximum for the selected waveform 40Msamples s for ARB and Sequence 0 005Hz to 100kKHz internal dc to 1MHz external Internal from keyboard previous channel next channel or trigger generator External from TRIG IN or remote interface 360 settable with 0 1 resolution subject to waveform frequency and type Frequency sweep capability is provided for both standard and arbitrary waveforms Arbitrary waveforms are expanded or condensed to exactly 4096 points and DDS techniques are used to perform the sweep Carrier Waveforms Sweep Mode Sweep Direction Sweep Range Sweep Time Marker Sweep Trigger Source Sweep Hold Multi channel sweep All standard and arbitrary except pulse pulse train and sequence Linear or logarithmic triggered or continuous Up down up down or down up From 1mHz to 16 MHz in one range Phase continuous Independent setting of the start and stop frequency 30ms to 999s 3 di
48. INPUT screen is currently selected the status field will change from no hold to ext hold whilst the waveform is paused Modulation Introduction Both internal and external modulation can be selected External modulation can be applied to any or all channels Internal modulation uses the previous channel as the modulation source e g channel 2 can be used to modulate channel 3 internal modulation is not available on channel 1 or on a single channel instrument The external modulation mode can be set to VCA Voltage Controlled Amplitude or SCM Suppressed Carrier Modulation modes Internal modulation can be set to true AM Amplitude Modulation or SCM Modulation modes share some of the generator s inter channel resources with Sum modes as a result there are some restrictions on using Modulation and Sum together but these are generally outside the range of common sense applications To better understand these constraints the following sections and the SUM chapter should be read with reference to the fold out block diagrams at the end of the manual which show the control signals of a single channel and the inter channel connections These diagrams also show the inter channel trigger connections described in the Triggered Burst and Gate chapter in general inter channel triggering is possible simultaneously with modulation but few combinations are of real use External Modulation Pressing the MODULATION key calls the MODULATI
49. L specified Set the modulation source to lt OFF gt lt EXT gt or lt PREV gt Set the modulation type to lt AM gt or lt SCM gt Set the depth for amplitude modulation to lt nrf gt Set the level for SCM to lt nrf gt Volts Set the sum source to lt OFF gt lt EXT gt or lt PREV gt Set the sum input attenuator to lt OdB gt lt 10dB gt lt 20dB gt lt 30dB gt lt 40dB gt or lt 50dB gt Set the sum ratio to lt nrf gt Set the ref clock bnc to lt IN gt lt OUT gt lt MASTER gt or lt SLAVE gt Aborts an external phase locking operation Set the generator phase to lt nrf gt degrees This parameter is used for phase locking and trigger gate mode start stop phase Set the channel lock mode to lt INDEP gt lt MASTER gt lt FTRACK gt or lt SLAVE gt Set the inter channel lock status to lt ON gt or lt OFF gt 89 Status Commands CLS ESE lt nrf gt ESE ESR IDN ST OPC OPC PRE lt nrf gt PRE SRE lt nrf gt SRE STB WAI TST EER QER 90 Clear status Clears the Standard Event Status Register Query Error Register and Execution Error Register This indirectly clears the Status Byte Register Set the Standard Event Status Enable Register to the value of lt nrf gt Returns the value in the Standard Event Status Enable Register in lt nr1 gt numeric format The syntax of the response is lt nr1 gt lt
50. MHz done 0 A new marker frequency can be programmed directly from the keyboard or by using the rotary control and cursor keys Note that the marker frequency can only be one of the values in the sweep frequency table any value in the sweep range can be entered but the actual value will be the nearest frequency in the table When sweep is turned on the actual marker frequency is shown in the non editable field below the programmed frequency For the default sweep setting of 100kHz to 10MHz in 50ms 400 steps the actual frequency of a 5MHz marker is 4 977 MHz The marker duration is for the number of 0 5ms intervals that the frequency remains at the marker value for fast and or wide sweeps this will often be the 0 5ms minimum but for slow and or narrow spans the marker may last many 0 5ms intervals To avoid anomalous conditions the marker will not be exactly placed at the start and stop frequencies even though it can be programmed to be so The marker polarity and level is setup on the cursor marker menu of the UTILITY screen see System Operations section 31 The marker frequency can be changed with sweep on but since the table of frequency values is rebuilt with each change this can be a slow process especially if the rotary control is used It is faster to switch sweep off change the marker and switch sweep back on again Sweep Hold The sweep can be held restarted at any time at from its current frequency by alternate presses of
51. ON set up screen MODULATION source ext 0 type VCA The source soft key steps the modulation choice between off external and CHx where x is the number of the previous channel note that channel 1 does not have a previous channel refer to the Inter Channel Block Diagram With ext selected the modulation can be switched between VCA and sc M with alternate presses of the type soft key Both types of external modulation can be used with internal or external Sum External modulation can be applied to any or all channels External VCA Select VCA withthe type soft key onthe MODULATION screen Connect the modulating signal to the EXT MODULATION socket nominally 1kQ input impedance a positive voltage increases the channel output amplitude and a negative voltage decreases the amplitude Note that clipping will occur if the combination of channel amplitude setting and VCA signal attempts to drive the output above 20Vpp open circuit voltage External AM is achieved by setting the channel to the required output level and applying the modulation signal which can be AC coupled if required at the appropriate level to obtain the modulation depth required If the channel output level is changed the amplitude of the modulating signal will have to be changed to maintain the same modulation depth 57 The VCA signal is applied to the amplifier chain prior to the output attenuators The amplifier itself is controlled over a limited range 10
52. POSNMKR gt lt BSTDONE gt lt SEQSYNC gt lt TRIGGER gt lt SWPTRG gt or lt PHASLOC gt Delete tone frequency number lt nrf gt thus defining the end of the list Set tone frequency number lt nrf1 gt to lt nrf2 gt Hz The third parameter sets the tone type 1 will give Trig 2 will give FSK any other value gives Gate type Set the trig input to lt INT gt lt EXT gt lt MAN gt lt PREV gt lt NEXT gt lt POS gt or lt NEG gt Set the trig output to lt AUTO gt lt WFMEND gt lt POSNMKR gt lt SEQSYNC gt or lt BSTDONE gt Set the internal trigger generator period to lt nrf gt sec Set the vca sum input to lt VCA gt lt SUM gt or lt OFF gt Select the output waveform as lt SINE gt lt SQUARE gt lt TRIANG gt lt DC gt lt POSRMP gt lt NEGRMP gt lt COSINE gt lt HAVSIN gt lt HAVCOS gt lt SINC gt lt PULSE gt lt PULSTRN gt lt ARB gt or lt SEQ gt Set the waveform frequency to lt nrf gt Hz Set the waveform period to lt nrf gt sec Set the output load which the generator is to assume for amplitude and dc offset entries to lt 50 gt 50Q lt 600 gt 600Q or lt OPEN gt 95 Maintenance The Manufacturers or their agents overseas will provide a repair service for any unit developing a fault Where owners wish to undertake their own maintenance work this should only be done by skilled personnel in conjunction with the service manual which may be purchased
53. RAM and each given a name the number that can be stored depends on the number of points in each waveform Arb waveforms can be created using basic front panel editing capabilities particularly useful for modifying existing standard or arb waveforms or by using waveform design software that enables the user to create waveforms from mathematical expressions from combinations of other waveforms or freehand see Appendix 4 Arb Waveform Terms The following terms are used in describing arb waveforms e Horizontal Size The number of horizontal points is the time component of the waveform The minimum size is 4 points and the maximum is 65536 points e Waveform Address Each horizontal point on an arb waveform has a unique address Addresses always start at 0000 thus the end address is always one less than the horizontal size e Arb Frequency and Waveform Frequency The arb frequency is the clock rate of the data RAM address counters and has a range of 0 1Hz to 40MHz on this instrument The waveform frequency depends on both the arb frequency and horizontal size A 1000 point waveform clocked at an arb frequency of 40MHz has a waveform frequency of 40e6 1000 40kHz e Data Value Each horizontal point in the waveform has an amplitude value in the range 2048 to 2047 e Arb Waveform Amplitude When playing arb waveforms the maximum output amplitude will depend on both the range of data values and the output amplitude setting A waveform that
54. Sequence 40MS s clock 0 only 35 Manual Initialisation of Inter channel Triggering If a multi channel instrument is set up such that all channels are triggered by an adjacent one it is possible to have a stable condition where all channels are waiting for a trigger and the sequence of triggered bursts never starts To overcome this problem any channel can be triggered manually and independently using the force soft key on that channel s TRIGGER IN screen select the channel to start the sequence with the appropriate SETUP key select the TRIGGER IN screen with the TRIG IN key and press the force soft key Gated Mode Gated mode is turned on with the gated soft key onthe MODE screen The setup soft key on this screen accesses the TRIGGER GATE SETUP screen on which the start phase is set The other parameters associated with Gated are set on the TRIGGER IN setup screen called by pressing the TRIG IN key TRIGGER IN force 0 source internal slope positive period 2 00ms Gate Source The gate signal source can be selected with the source soft key onthe TRIGGER IN setup screen tobe internal external or either of the adjacent channels With internal selected the internal trigger generator is used to gate the waveform the duration of the gate is half the generator period see Internal Trigger Generator section With external selected the gate duration is from the point nominally 1 5 Volts on the specified edge of the
55. TGA1240 40 MHz Arbitrary Waveform Generator User Manual Manual Copyright 2000 T T Instruments Ltd All rights reserved Software Copyright 2000 T T Instruments Ltd All rights reserved Waveform Manager Plus 2000 T T Instruments All rights reserved Overview amp Introduction Specifications Safety EMC Installation Connections Front Panel Connections Rear Panel Connections General Initial Operation Principles of Operation Standard Waveform Operation Setting Generator Parameters Warnings and Error Messages SYNC Output Sweep Operation General Setting Sweep Parameters Triggered Burst and Gate General Triggered Burst Gated Mode Sync Out in Triggered Burst and Gated Mode Tone Mode Arbitrary Waveform Generation Introduction Creating New Waveforms Modifying Arbitrary Waveforms Arbitrary Waveform Sequence Frequency and Amplitude Control with Arbitrary Waveforms Sync Out Settings with Arbitrary Waveforms Waveform Hold in Arbitrary Mode Output Filter Setting Pulse and Pulse trains Pulse Set up Pulse train Setup Waveform Hold in Pulse and Pulse Train Modes Table of Contents 12 13 14 16 16 17 19 19 21 23 23 25 27 28 28 29 33 33 34 36 37 38 40 40 42 43 48 49 50 50 51 52 52 53 55 Modulation Introduction External Modulation Internal Modulation Sum Inter Channel Synchronisation Synchronising Two Generators System Operations from the Utility Menu Calibration Remote Operatio
56. Vpk pk input for 20Vpk pk output Typically 1kQ Holds an arbitrary waveform at its current position A TTL low level or switch closure causes the waveform to stop at the current position and wait until a TTL high level or switch opening which allows the waveform to continue The front panel MAN HOLD key or remote command may also be used to control the Hold function While held the front panel MAN TRIG key or remote command may be used to return the waveform to the start The Hold input may be enabled independently for each channel Input Impedance 10kQ Ref Clock In Out Set to Input Set to Output Set to Phase Lock Input for an external 10MHz reference clock TTL CMOS threshold level Buffered version of the internal 10MHz clock Output levels nominally 1V and 4V from 50Q Used together with SYNC OUT on a master and TRIG IN on a slave to synchronise phase lock two separate generators INTER CHANNEL OPERATION Inter channel Modulation The waveform from any channel may be used to Amplitude Modulate AM or Suppressed Carrier Modulate SCM the next channel Alternatively any number of channels may be Modulated AM or SCM with the signal at the MODULATION input socket Carrier frequency Carrier waveforms Modulation Types AM SCM Modulation source Frequency Range Internal AM Depth Resolution Carrier Suppression SCM External Modulation Signal Range Inter channel Analog Summing Ent
57. X 2 2 a RX TX 3 3 m TX DTR 4 O4 GND 5C 25 GND DSR a 6 O6 RTS 7 O7 CTS 8 O8 LINKS TO RI 90 NULL OUT PC O9 Baud Rate is set as described above in Address and Baud Rate Selection the other parameters are fixed as follows Start Bits 1 Data Bits 8 Addressable RS232 Connections For addressable RS232 operation pins 7 8 and 9 of the instrument connector are also used Using a simple cable assembly a daisy chain connection system between any number of instruments up to the maximum of 32 can be made as shown below CONTROLLER INSTRUMENT INSTRUMENT INSTRUMENT 1 2 3 TO NEXT INSTRUMENT The daisy chain consists of the transmit data TXD receive date RXD and signal ground lines only There are no control nandshake lines This makes XON XOFF protocol essential and allows the inter connection between instruments to contain just 3 wires The wiring of the adaptor cable is shown below Parity None Stop Bits 1 75 9 WAY D PANAY FEMALE MALI DCD 1 O O1 RX 20 O2 TX TX 30 O3 mm RX DTR _ 4 O 4 O4 GND sO 5 GND DSR 6 O O6 RTS 7 O O7 CTS 8 O Os RI 30 x og LINKS TO CONTROLLER M OUT ec CHAIN lt O OO0O0O0 9 WAY D 123456789 MLE AN INSTRUMENT i 1 ON THE CHAIN TX RX TXIN RXOQUT All instruments on the interface must be set to the sa
58. ame screws 5 To comply with safety standard requirements the operating voltage marked on the rear panel must be changed to clearly show the new voltage setting 6 Change the fuse to one of the correct rating see below 230V 115V 100V OV Single Channel for 230V operation connect the live brown wire to pin 15 for 115V operation connect the live brown wire to pin 14 for 100V operation connect the live brown wire to pin 13 2 and 4 Channel BROWN BLUE BROWN BLUE BROWN BLUE 230V 115V 100V for 230V operation link pins 15 amp 16 for 115V operation link pins 13 amp 16 and pins 15 amp 18 for 100V operation link pins 13 amp 16 and pins 14 amp 17 14 Fuse Ensure that the correct mains fuse is fitted for the set operating voltage The correct mains fuse types are Single channel for 230V operation 250 mA T 250V HRC for 100V or 115V operation 500 mA T 250V HRC 2 amp 4 channel for 230V operation 1A T 250V HRC for 100V or 115V operation 2A T 250V HRC To replace the fuse disconnect the mains lead from the inlet socket and withdraw the fuse drawer below the socket pins Change the fuse and replace the drawer The use of makeshift fuses or the short circuiting of the fuse holder is prohibited Mains Lead When a three core mains lead with bare ends is provided it should be connected as follows Brown Mains Live Blue Mains Neutral Green Yellow Mains Earth WARNING
59. an oscilloscope or for slow sweeps a recorder An oscilloscope or recorder can be triggered by connecting its trigger input to the generator s SYNC OUT SYNC OUT defaults to sweep sync when sweep is turned on sweep sync goes high at the start of sweep and low at the end of sweep At the end of sweep it is low long enough for an oscilloscope to retrace for example To show a marker on the display instrument the rear panel CURSOR MARKER OUT socket should be connected to a second channel Alternatively for an oscilloscope the signal can be used to modulate the Z axis See Sweep Marker section for setting marker frequency The cursor marker polarity and level is set up on the cursor marker menu of the UTILITY screen see System Operations section For triggered sweeps a trigger signal must be provided at the front panel TRIG IN socket or by pressing the MAN TRIG key or by a remote command The function of TRIG IN is automatically defaulted to external when triggered sweep is selected a sweep is initiated by the rising edge of the trigger signal The generator does not provide a ramp output for use with X Y displays or recorders Setting Sweep Parameters Pressing the SWEEP key or the sweep setup soft key onthe MODE screen displays the SWEEP SETUP screen SWEEP SETUP off Orange type Otime spacing manual marker Menus for setting up the range time sweep rate type continuous triggered etc spacing lin
60. arameter for sequence segment lt nrf gt to lt COUNT gt lt TRGEDGE gt or lt TRGLEV gt Set the waveform parameter for sequence segment lt nrf gt to lt cpd gt Set the sum source to lt OFF gt lt EXT gt or lt PREV gt Set the sum input attenuator to lt OdB gt lt 10dB gt lt 20dB gt lt 30dB gt lt 40dB gt or lt 50dB gt Set the sum ratio to lt nrf gt Set the sweep centre frequency to lt nrf gt Hz Set the sweep direction to lt UP gt lt DOWN gt lt DNUP gt or lt UPDN gt Set the sweep manual parameters to lt UP gt lt DOWN gt lt FAST gt lt SLOW gt lt WRAPON gt or lt WRAPOFF gt Set the sweep marker to lt nrf gt Hz Set the sweep spacing to lt LIN gt or lt LOG gt Set the sweep frequency span to lt nrf gt Hz Set the sweep start frequency to lt nrf gt Hz Set the sweep stop frequency to lt nrf gt Hz SWPSYNC lt cpd gt SWPTIME lt nrf gt SWPTYPE lt cpd gt SYNCOUT lt cpd gt TONEEND lt nrf gt TONEFREQ lt nrf1 gt lt nrf2 gt lt nrf3 gt TRIGIN lt cpd gt TRIGOUT lt cpd gt TRIGPER lt nrf gt VCAIN lt cpd gt WAVE lt cpd gt WAVFREQ lt nrf gt WAVPER lt nrf gt ZLOAD lt cpd gt Set the sweep sync lt ON gt or lt OFF gt Set the sweep time to lt nrf gt sec Set ten sweep type to lt CONT gt lt TRIG gt lt THLDRST gt or lt MANUAL gt Set the sync output lt ON gt lt OFF gt lt AUTO gt lt WFMSYNC gt lt
61. art and finish at The baseline can be set between 5 0V and 5 0V by direct keyboard entries or by using the rotary control Note that the actual baseline level at the output will only be as set in this field if the output amplitude is set to maximum 10Vpp into 50Q on the AMPLITUDE screen and terminated in 50Q If the amplitude was set to 5Vpp into 50Q then the actual baseline range would be 2 5V to 2 5V for set values of 5 0 to 5 OV i e the amplitude control scales the baseline setting The actual output levels are doubled when the output is unterminated Pressing next on this screen calls the first of 3 screens for the first pulse in the pattern Pulse 1 level 5 000 V done next The pulse level can be set on this screen between 5 0V and 5 0V by direct keyboard entries or by using the rotary control As with the baseline level described above the set pulse levels are only output if the amplitude setting is set to maximum 10Vpp into 50Q on the AMPLITUDE screen and terminated in 50Q Adjusting the amplitude scales both the peak pulse levels and baseline together thus keeping the pulse shape in proportion as the amplitude is changed exactly as for arb waveforms Actual output levels are doubled when the output is unterminated Note that by pressing the Pulse soft key on this and subsequent screens the pulse to be edited can be directly set from the keyboard or by using the rotary control this is useful in d
62. ate when this is the case the actual phase is shown in brackets as a non editable field below the programmed value To achieve start phase precision all waveforms are run in Clock Synthesis mode i e as if they were arbitrary waveforms when Gated mode is specified this limits actual frequency resolution to 4 digits for all waveforms although the normally DDS generated waveforms are still entered with 7 digit precision Sine cosine haversine etc waveforms are created as if they were arbitrary waveforms with the first point of the waveform exactly at the start phase each time the phase or frequency is changed the waveform is recalculate which can cause a slight lag if these parameters are being changed quickly with the rotary knob The phase resolution of true arbitrary waveforms is limited by the waveform length since the maximum resolution is 1 clock thus waveforms with a length gt 3600 points will have a resolution of 0 1 but below this number of points the maximum resolution becomes 360 number of points Square waves pulse pulse trains and sequences have no start phase adjustment phase is fixed at 0 Refer to the table in the Triggered Burst section for a summary of start phase capabilities Sync Out in Triggered Burst and Gated Mode When Triggered Burst or Gated modes are selected the SYNC OUT source automatically defaults to trigger trigger is apositive edged signal synchronised to the actual trigger used whether internal from
63. but some are of little use Channel Selection Most commands act on a particular channel of the generator The following command is used to select the required channel Subsequent commands will change only the specified parameter on the selected channel SETUPCH lt nrf gt Select channel lt nrf gt as the destination for subsequent commands lt nrf gt may take the range 1 to maximum channel number in the instrument Frequency and Period 84 These commands set the frequency period of the generator main output and are equivalent to pressing the FREQ key and editing that screen WAVFREQ lt nrf gt Set the waveform frequency to lt nrf gt Hz WAVPER lt nrf gt Set the waveform period to lt nrf gt sec CLKFREQ lt nrf gt Set the arbitrary sample clock freq to lt nrf gt Hz CLKPER lt nrf gt Set the arbitrary sample clock period to lt nrf gt sec AMPL lt nrf gt AMPUNIT lt cpd gt ZLOAD lt cpd gt DCOFFS lt nrf gt Waveform Selection WAVE lt cpd gt PULSPER lt nrf gt PULSWID lt nrf gt PULSDLY lt nrf gt PULTRNLEN lt nrf gt PULTRNPER lt nrf gt PULTRNBASE lt nrf gt PULTRNLEV lt nrf1 gt lt nrf2 gt PULTRNWID lt nrf1 gt lt nrf2 gt PULTRNDLY lt nrf1 gt lt nrf2 gt PULTRNMAKE ARB lt cpd gt ARBLISTCH ARBLIST Amplitude and DC Offset Set the amplitude to lt nrf gt in the units as specified by the AMPUNIT command Set the amplitude units to lt VPP gt lt VRMS gt
64. ch 2048 and 2047 if the maximum value range is 1024 to 1023 for example then the maximum peak to peak voltage will only be 10Vpp for the instrument set to 20Vpp Sync Out Settings with Arbitrary Waveforms The default setting for Sync Out when arbitrary waveforms are selected is waveform sync this is a pulse that starts coincident with the first point of the waveform and is a few points wide If a waveform sequence has been selected then Sync Out defaults to sequence sync this is a waveform which goes low during the last cycle of the last waveform in a sequence and is high at all other times When sequence is used in Triggered Burst mode the burst count is a count of the number of complete sequences Waveform Hold in Arbitrary Mode Arbitrary waveforms can be paused and restarted on any channel by using the front panel MAN HOLD key or a signal applied to the rear panel HOLD IN socket 50 On multi channel instruments the channels which are to be held by the MAN HOLD key or HOLD IN socket must first be enabled using the ARB HOLD INPUT screen accessed by pressing the HOLD key ARB HOLD INPUT status no hold mode disabled Each channel is selected in turn using the channel SETUP keys and set using the mode soft key the mode changes between disabled and enabled with alternate key presses Pressing the front panel MAN HOLD key stops the waveform at the current level on all enabled channels pressing MAN HOLD a second time r
65. ch is the master Do not apply external voltages exceeding 10V 16 SUM IN This is the input socket for external signal summing The channel s with which this signal is to be summed are selected on the SUM screen A Do not apply external voltages exceeding 10V MODULATION IN This is the input socket for external modulation Any number of channels may be AM or SCM modulated with this signal the target channels are selected on the MODULATION screen Do not apply external voltages exceeding 10V Rear Panel Connections REF CLOCK IN OUT The function of the CLOCK IN OUT socket is set from the ref clock i o menu on the UTILITY screen see System Operations section input This is the default setting The socket becomes an input for an external 10MHz reference clock The system automatically switches over from the internal clock when the external reference is applied output The internal 10MHz clock is made available at the socket phase lock When two or more generators are synchronised the slaves are set to phase lock slave andthe masterissetto phase lock master As an output the logic levels are nominally 1V and 4V from typically 50Q CLOCK OUT will withstand a short circuit As an input the threshold is TTL CMOS compatible AN Do not apply external voltages exceeding 7 5V or 2 5V to this signal connection HOLD IN Controls the waveform hold function The input impedance is nominally 10kQ A Do not apply external
66. d 4 channel instruments in the text it is obvious when the description applies only to a multi channel instrument Introduction This synthesised programmable arbitrary waveform generator has the following features e 1 2 or 4 independent arb channels e Up to 40MHz sampling frequency Sinewaves and square waves up to 16MHz e 12 bit vertical resolution e 64k points horizontal resolution per channel 256k point non volatile waveform memory Waveform linking looping and sequencing e Interchannel triggering summing modulation and phase control GPIB and RS232 interfaces The instrument uses a combination of direct digital synthesis and phase lock loop techniques to provide high performance and extensive facilities in a compact instrument It can generate a wide variety of waveforms between 0 1mHz and 16MHz with high resolution and accuracy Arbitrary waveforms may be defined with 12 bit vertical resolution and from 4 to 65536 horizontal points In addition a number of standard waveforms are available including sine square triangle ramp and pulse Arbitrary waveforms may be replayed at a user specified waveform frequency or period or the sample rate may be defined in terms of period or frequency Extensive waveform editing features between defined start and end points are incorporated including waveform insert point edit line draw amplitude adjust and invert More comprehensive features are available using the arbitrary
67. d gt lt bin data block gt ARBDATA lt cpd gt 92 Remote Command Summary Clear status Set the Standard Event Status Enable Register to the value of lt nrf gt Returns the value in the Standard Event Status Enable Register in lt nr1 gt numeric format Returns the value in the Standard Event Status Register in lt nr1 gt numeric format Returns the instrument identification Returns ist local message as defined by IEEE Std 488 2 Returns the complete set up of the instrument as a hexadecimal character data block approximately 842 bytes long Sets the Operation Complete bit bit 0 in the Standard Event Status Register Query operation complete status Set the Parallel Poll Enable Register to the value lt nrf gt Returns the value in the Parallel Poll Enable Register in lt nr1 gt numeric format Recalls the instrument set up contained in store number lt nrf gt Resets the instrument parameters to their default values Saves the complete instrument set up in the store number lt nrf gt Valid store numbers are 1 9 Set the Service Request Enable Register to lt nrf gt Returns the value of the Service Request Enable Register in lt nr1 gt numeric format Returns the value of the Status Byte Register in lt nr1 gt numeric format This command is the same as pressing the MAN SYNC key The generator has no self test capability and the response is always O lt rmt gt Wait for operation complete tru
68. d precise phase differences can be set between the channels Two generators can also be synchronised see Synchronising Two Generators chapter giving a maximum of 8 channels that can be operated in synchronisation Restrictions apply to certain waveform and frequency combinations these are detailed in the following sections Synchronising Principles Frequency locking is achieved by using the clock output from a master channel to drive the clock inputs of slaves Any channel can be a master only 1 master allowed and any or all the others can be slaves master slaves and independent channels can be mixed on the same instrument When frequency locking is switched on the internal lock signal from the CPU locks the channels at the specified inter channel phase and re locks them automatically every time the frequency is changed The clock and internal lock signals are shown in the Inter Channel Block Diagram at the end of the manual Channels to be locked together must all be operating in continuous mode For DDS generated waveforms see Principles of Operation in the General chapter it is the 27 4878 MHz signal that is distributed from master to slaves and channels can in principle be frequency locked with any frequency combination However the number of cycles between the phase referenced points will be excessively large unless the ratio is a small rational number e g 2kHz could be locked usefully with 10kKHz 50kHz 100KHz e
69. dB and the full amplitude range of the channel is achieved by switching in up to five 10dB attenuation stages Peak modulation cannot exceed the maximum of the range within which the channel output has been set by choice of amplitude setting Whereas with internal AM the generator gives warnings when the combination of modulation depth and amplitude setting cause waveform clipping see Internal Modulation section it is up to the user to observe the waveforms when using external VCA and to make adjustments if the waveform is clipping Note that it is not possible to give a simple guide as to where the range breakpoints are because the use of DC Offset for example changes these points Within each range the maximum output setting of the channel at which clipping is avoided is reduced from range maximum to half this value as modulation is increased by 0 to 100 100 modulation will be achieved at this mid range setting with an external VCA signal of approximately 1Vpp Modulation frequency range is DC to 100kHz It is also possible to modulate a DC level from the generator with a signal applied to the EXT MODULATION socket as follows Set the generator to external trigger on the TRIGGER IN setup screen but do not apply a trigger signal to TRIG IN select squarewave The MAIN OUT is now set at the peak positive voltage defined by the amplitude setting pressing the key with AMPLITUDE displayed will set the level to the peak negat
70. directly from the Manufacturers or their agents overseas Cleaning 96 If the instrument requires cleaning use a cloth that is only lightly dampened with water or a mild detergent WARNING TO AVOID ELECTRIC SHOCK OR DAMAGE TO THE INSTRUMENT NEVER ALLOW WATER TO GET INSIDE THE CASE TO AVOID DAMAGE TO THE CASE NEVER CLEAN WITH SOLVENTS Appendix 1 Warning and Error Messages Warning messages are given when a setting may not give the expected result e g DC Offset attenuated by the output attenuator when a small amplitude is set the setting is however implemented Error messages are given when an illegal setting is attempted the previous setting is retained The last two warning error messages can be reviewed by selecting LAST ERROR from the UTILITY screen the latest is reported first Warning and error messages are reported with a number on the display only the number is reported via the remote control interfaces The following is a complete list of messages as they appear on the display Warning Messages 00 13 14 23 24 30 42 43 59 81 83 No errors or warnings have been reported DC offset changed by amplitude Offset SUM level may cause clipping Offset will clip the waveform Instrument not calibrated Amplitude will clip the waveform Trigger source is fixed to external in SWP SLAVE mode Arb repeated in two seq segs so SEQ SYNC may not be correct Trigger slope is fixed to positive in SWEEP SLAVE
71. e positive or negative of the external trigger signal that is used to initiate a burst The default setting of positive should be used for triggering by the Internal Trigger Generator or an adjacent channel s Trigger Out Note that the trigger signal from SYNC OUT used for synchronising the display of a triggered burst on an oscilloscope for example is always positive going at the start of the burst Burst Count The number of complete cycles in each burst following the trigger is set from the TRIGGER GATE SETUP screen called by pressing setup onthe MODE screen TRIGGER GATE SETUP burst cnt 0000001 Ophase 000 0 actual 000 0 The required count can be set by pressing the burst cnt soft key followed by direct entries from the keyboard or by using the rotary control The maximum number of waveform cycles that can be counted is 1048575 27 1 Start Phase The start phase i e the point on the waveform cycle at which the burst starts can be selected by pressing the phase soft key followed by direct entries from the keyboard or by using the rotary control Since the waveform cycle is always completed at the end of the burst the start phase is also the stop phase The phase can be set with a precision of 0 1 but the actual resolution is limited with some waveforms and at certain waveform frequencies as detailed below To indicate when this is the case the actual phase is shown in brackets as a non editable field b
72. e executed before the next is started Aborts a phase locking operation Set the depth for amplitude modulation to lt nrf gt Set the amplitude to lt nrf gt in the units as specified by the AMPUNIT command Set the amplitude units to lt VPP gt lt VRMS gt or lt DBM gt Select an arbitrary waveform for output Adjust the amplitude of arbitrary waveform lt cpd gt from start address lt nrf1 gt to stop address lt nrf2 gt by the factor lt nfr3 gt Delete the arb lt cpd gt from channel memory Block copy in arbitrary waveform lt cpd gt the data from start address lt nrf1 gt to stop address lt nrf2 gt to destination address lt nrf3 gt Create a new blank arbitrary waveform with name lt cpd gt and length lt nrf gt points Load data to an existing arbitrary waveform Returns the data from an existing arbitrary waveform ARBDATACSV lt cpd gt lt csv ascii data gt ARBDATACSV lt cpd gt ARBDEF lt cpd gt lt nrf gt lt bin data block gt ARBDEFCSV lt cpd gt lt nrf gt lt csv ascii data gt ARBDELETE lt cpd gt ARBEDLMTS lt nrf1 gt lt nrf2 gt ARBINSARB lt cpd1 gt lt cpd2 gt lt nrf1 gt lt nrf2 gt ARBINSSTD lt cpd1 gt lt cpd2 gt lt nrf1 gt lt nrf2 gt ARBINVERT lt cpd gt lt nrf1 gt lt nrf2 gt ARBLEN lt cpd gt ARBLINE lt cpd gt lt nrf1 gt lt nrf2 gt lt nrf3 gt lt nrf4 gt ARBLIST ARBLISTCH ARBOFFSET lt cpd gt lt nrf1 gt lt nrfi2 g
73. een Manual Sweep Pressing the manual soft key on the SWEEP SETUP screen calls the MANUAL SWEEP FREQ screen MANUAL SWEEP FREQ 1 630 MHz step fast wrap gt step slow done 0 Before manual control canbe used manual must be selected onthe SWEEP TYPE screen see above if manual has not been set the message mode is not manual will be displayed instead of the frequency In manual mode the frequency can be stepped through the sweep range defined on the SWEEP RANGE screen using the rotary control or cursor keys Every point of the frequency table is stepped through if step slow is selected if step fast is set then the frequency changes in multiple step increments Step fast cannot be set when the number of steps in the table is small If wrap is set the sweep wraps round from start frequency to stop frequency and vice versa if no wrap is set the sweep finishes at either the start or stop frequency depending on the direction of the rotary control or cursor keys Sweep Spacing Pressing the spacing soft key on the SWEEP SETUP screen calls the SWEEP SPACING screen SWEEP SPACING logarithmic Olinear With linear selected the sweep changes the frequency at a linear rate with logarithmic selected the sweep spends an equal time in each frequency decade Sweep Marker Pressing the marker soft key on the SWEEP SETUP screen calls the SWEEP MARKER FREQ screen SWEEP MARKER FREQ progrm 5 000 MHz actual 4 977
74. elow the programmed value To achieve start phase precision all waveforms are run in Clock Synthesis mode i e as if they were arbitrary waveforms when Triggered Burst is specified this limits actual frequency resolution to 4 digits for all waveforms although the normally DDS generated waveforms are still entered with 7 digit precision Sine cosine haversine etc waveforms are created as if they were arbitrary waveforms with the first point of the waveform exactly at the start phase each time the phase or frequency is changed the waveform is recalculated which can cause a slight lag if these parameters are being changed quickly with the rotary knob The phase resolution of true arbitrary waveforms is limited by the waveform length since the maximum resolution is 1 clock thus waveforms with a length gt 3600 points will have a resolution of 0 1 but below this number of points the maximum resolution becomes 360 number of points Square waves pulse pulse trains and sequences have no start phase adjustment phase is fixed at 0 Asummary of start phase capabilities in Triggered Burst mode is shown in the table below Waveform Max Wfm Freq Phase Control Range amp Resolution Sine cosine haversine havercosine 1MHz 360 0 1 Square 1MHz 0 only Triangle 100kHz 360 0 1 Ramp 100kHz 360 0 1 Sin x x 100kHz 360 0 1 Pulse amp Pulse Train 10MHz 0 only Arbitrary 40MS s clock 360 300 length or 0 1
75. emory until they have first been deleted from all channel memories waveforms cannot be deleted from a channel s memory if it is being output on that channel The waveform must first be deselected on each channel by selecting alternative waveforms on those channels from the STANDARD WAVEFORMS or ARBS screens The waveform can then be deleted from each channel memory in turn by selecting the ARBS screen for that channel ARBS chan mem owv00 01024 del ewv01 03872 Owv02 00500 del A del soft key will appear against those waveforms in the channels memory which are not in use press the appropriate del soft key to delete the waveform from channel memory The deletion from backup memory described above can then be actioned Edit Waveform Pressing the edit waveform soft key calls the EDIT FUNCTIONS menu 44 EDIT FUNCTIONS Opoint edit Oline draw Owave insert From this menu can be selected functions which permit the waveform to be edited point by point point edit by drawing lines between two points line draw or by inserting all or part of an existing waveform into the waveform being edited wave insert In addition sections of the waveform can be selected and their peak to peak level changed using wave amplitude or baseline changed using wave offset Sections of the waveform can be copied into itself block copy and position markers for use at Sync Out can also be defined Pressing the exit soft key
76. enu can be exited by pressing the cancel soft key which keeps the name but does not implement the copy or by pressing the create soft key which makes the copy and directly calls the MODIFY screen to permit waveform editing Modifying Arbitrary Waveforms Read the Arb Waveform Creation and Modification General Principles section for a summary of the general restrictions applying to waveform modification Pressing the MODIFY front panel key or the create soft key on either of the CREATE NEW WAVEFORM menus calls the MODIFY screen MODIFY wv01 gt resize rename delete info 0 Yedit waveform This screen gives access to a number of menus which permit the selected waveform to be resized renamed edited etc The arb waveform to be modified is selected using the rotary control or cursor keys to step through all possible choices the current choice is displayed on the top line beside MODIFY Waveform Edit Cursor During any arbitrary waveform modify procedure which involves setting waveform addresses waveform cursor s can be output from the rear panel CURSOR MARKER OUT socket For this to happen the waveform being edited must be running on the output currently selected by the channel SETUP keys The amplitude polarity and width of the cursor is set on the cursor marker menu of the UTILITY screen see System Operations section The cursors are positioned at the start and stop addresses used for the various edit opera
77. equency of the master is changed the frequency of the slaves also change and the slaves are re locked to the master Master freq is the default mode when the waveforms are Clock Synthesised arbs pulses etc if master has been set instead the mode will automatically change to master freq when locking is turned on The frequency of Clock Synthesised waveform slaves always therefore tracks the master Finally slave selects those channel s which are to be locked to the master At any time pressing the view soft key gives a graphical view of the master slave set up see below for an example CH gt 123 4 indep Y master Y slave YY exit Channel locking is turned on or off withthe status soft key Any illegal setting combinations will result in an error message when an attempt is made to turn status on Any of the following conditions will cause an error see also the Synchronising Principles section for a discussion of the set up constraints 1 More than one master channel is enabled 2 No master channel is enabled 3 The locked channels contain a mixture of DDS and PLL generated waveforms 4 Frequency tracking is enabled mode master freq but the frequencies are not the same on all channels If PLL waveforms are locked the mode will be forced to frequency tracking A locked channel is not set to continuous mode 6 An attempt is made to turn on phase lock with a frequency set too high Note that the ma
78. eriod entries that cannot be exactly set are accepted and rounded up to the nearest available value e g 109ms is rounded to 11ms When Triggered Burst or Gated modes are selected the SYNC OUT source automatically defaults to trigger which is the output of the internal trigger generator when internal triggering or gating is specified In Triggered Burst mode the selected edge of each cycle of the trigger generator is used to initiate a burst the interval between bursts is therefore 0 01ms to 200s as set by the generator period In Gated mode the output of the main generator is gated on whilst the Internal Trigger Generator output is true the duration of the gate is therefore 005ms to 100s in step with trigger generator periods of 01ms to 200s External Trigger Input External trigger or gate signals are applied to the front panel TRIG IN socket which has a TTL level 1 5V threshold In Triggered Burst mode the input is edge sensitive the selected edge of each external trigger initiates the specified burst In Gated mode the input is level sensitive the output of the main generator is on whilst the gate signal is true The minimum pulse width that can be used with TRIG IN in Triggered Burst and Gated mode is 50ns and the maximum repetition rate is 1 MHz The maximum signal level that can be applied without damage is 10V When Triggered Burst or Gated modes are selected the SYNC OUT source automatically defaults to trigger which is always a posit
79. es a positive edged version is available at the triggered channel s SYNC OUT with its default source of trigger selected Triggered Burst Triggered Burst mode is turned on with the triggered soft key on the MODE screen The setup soft key on this screen accesses the TRIGGER GATE SETUP screen on which the burst count and start phase are set The other trigger parameters are set on the TRIGGER IN setup screen called by pressing the TRIG IN key TRIGGER IN force 0 source internal slope positive period 2 00ms Trigger Source 34 The trigger source can be selected with the source soft key on the TRIGGER IN setup screen tobe internal external manual or either of the adjacent channels With internal selected the internal trigger generator is used to initiate a burst this generator is set up as described in the previous section With external selected the specified edge of the signal at TRIG IN is used to initiate a burst With chan x selected the Trigger Out signal from adjacent channel x is used to initiate a burst the source of the Trigger Out signal on that channel x is set up as described in the previous section With manual selected as the source only pressing the MAN TRIG key or a remote command can be used to initiate a burst In multi channel instruments pressing MAN TRIG will trigger all those channels for which manual has been selected as the source Trigger Edge The slope soft key is used to select the edg
80. esponse formatter will wait indefinitely if necessary until the instrument is addressed to talk and the complete response message has been sent before the parser is allowed to start the next command in the input queue Commands must be sent as specified in the commands list and must be terminated with the command terminator code OAH Line Feed LF Commands may be sent in groups with individual commands separated from each other by the code 3BH The group must be terminated with command terminator OAH Line Feed LF Responses from the instrument to the controller are sent as specified in the commands list Each response is terminated by ODH Carriage Return CR followed by OAH Line Feed LF lt WHITE SPACE gt is defined as character codes OOH to 20H inclusive with the exception of those which are specified as addressable RS232 control codes lt WHITE SPACE gt is ignored except in command identifiers e g C LS is not equivalent to CLS The high bit of all characters is ignored The commands are case insensitive GPIB Remote Command Formats GPIB input to the instrument is buffered in a 256 byte input queue which is filled under interrupt in a manner transparent to all other instrument operations The queue contains raw un parsed data which is taken by the parser as required Commands and queries are executed in order and the parser will not start a new command until any previous command or query is complete There i
81. ess lt nrf gt in arbitrary waveform lt cpd gt to 0 low Put the pattern lt cpd2 gt into the arbitrary waveform lt cpd1 gt from start address lt nrf1 gt to stop address lt nrf2 gt The pattern may contain up to 16 entries of 1 or 0 no other characters are allowed Set the waveform parameter for sequence segment lt nrf gt to lt cpd gt lt cpd gt must be the name of an existing arbitrary waveform Set the step on parameter for sequence segment lt nrf gt to lt COUNT gt lt TRGEDGE gt or lt TRGLEV gt Set count for sequence segment lt nrf1 gt to lt nrf2 gt Set the status of sequence segment lt nrf gt to lt ON gt or lt OFF gt Set the mode to lt CONT gt lt GATE gt lt TRIG gt lt SWEEP gt or lt TONE gt Set the burst count to lt nrf gt Set the generator phase to lt nrf gt degrees This parameter is used for phase locking and trigger gate mode start stop phase Delete tone frequency number lt nrf gt thus defining the end of the list Set tone frequency number lt nrf1 gt to lt nrf2 gt Hz The third parameter sets the tone type 1 will give Trig 2 will give FSK any other value gives Gate type Set the sweep start frequency to lt nrf gt Hz Set the sweep stop frequency to lt nrf gt Hz Set the sweep centre frequency to lt nrf gt Hz Set the sweep frequency span to lt nrf gt Hz Set the sweep time to lt nrf gt sec Set the sweep type to lt CONT gt
82. estarts the waveform from that level Ifthe ARB HOLD INPUT screen is currently selected the status field will change from no hold to manual hold while the waveform is paused A logic low or switch closure at the rear panel HOLD IN socket also stops the waveform at the current level on all enabled channels a logic high or switch opening restarts the waveform from that level Ifthe ARB HOLD INPUT screen is currently selected the status field will change from no hold to ext hold while the waveform is paused If while the waveform is held by either of the above means the MAN TRIG key is pressed the waveform is reset to its first point the waveform will restart from this point when MAN HOLD is pressed again or a high is applied to the rear panel HOLD IN socket Output Filter Setting The output filter type is automatically chosen by the software to give the best signal quality for the selected waveform The choice can however be overridden by the user and this is most probably a requirement with arbitrary waveforms To change the filter press the FILTER key to call the FILTER SETUP screen FILTER SETUP mode auto type 10MHz eliptic The default mode is auto which means that the software selects the most appropriate filter With the setting on auto the type can be changed manually but the choice will revert to the automatic selection as soon as any relevant parameter is changed To override the automatic choice press the mode sof
83. et the limits for the arbitrary waveform editing functions to start at lt nrf1 gt and stop at lt nrf2 gt If both values are set to 0 the commands which use them will automatically place them at the start and end points of the relevant waveform This automatic mode will remain in effect until the ARBEDLMTS command is issued again with non zero values The automatic mode is always selected at power up Load data to an existing arbitrary waveform lt cpd gt must be the name of an existing arbitrary waveform The data consists of ascii coded values in the range 2048 to 2047 for each point The values are separated by a comma character and the data ends with lt pmt gt The data is entered into the arbitrary waveform between the points specified by the ARBEDLMTS command If less data is sent than the number of points between the limits the old data is retained from the point where the new data ends If more data is sent the extra is discarded ARBDATA lt cpd gt lt bin data block gt ARBDATACSV lt cpd gt ARBDATA lt cpd gt ARBRESIZE lt cpd gt lt nrf gt ARBRENAME lt cpd1 gt lt cpd2 gt ARBPOINT lt cpd gt lt nrf1 gt lt nrf2 gt ARBLINE lt cpd gt lt nrf1 gt lt nrfi2 gt lt nrf3 gt lt nrf4 gt ARBINSSTD lt cpd1 gt lt cpd2 gt lt nrf1 gt lt nrf2 gt ARBINSARB lt cpd1 gt lt cpd2 gt lt nrf1 gt lt nrf2 gt ARBCOPY lt cpd gt lt nrf1 gt lt nrfi2 gt lt nrf3 gt ARBAMPL lt cpd gt
84. form data points Waveform data may also be pasted to the clipboard for insertion into other programs Waveforms are displayed in fully scaleable windows and may be manipulated graphically Any number of waveforms in any of the supported types may be displayed simultaneously On line help is available in three ways 1 The help menu contains a contents option from which you can go to any section of the on line help file or browse particular areas or the whole file It is also possible to use the Index and Find operations of the Windows help system to search for items which are not listed directly in the contents section 2 Some dialog boxes have a Help button which when clicked will open the on line help file at the section containing the description of that dialog box 3 From most windows dialogues the F1 key will open the help file at the relevant section Waveform Manager allows you to keep waveforms for different projects separate from each other on your hard drive A project may be placed anywhere in any directory folder and all waveform files for that project will be stored in a structure below that directory A project is identified by a user defined name Each project maintains its own library of expressions Block Diagrams CHANNEL n Internal Trigger Generator Waveform end EXT TRIG In from front panel BNC Trigger In TRIGGERING Position marker Trigger Out to Trigger Out from CH n 1 Sequence end rT CH n 1 and CH n 1
85. ft at the factory default of 0000 no messages are shown and calibration can proceed as described in the Calibration Routine section only if a non zero password has been set will the user be prompted to enter the password Setting the Password On opening the Calibration screen press the password soft key to show the password screen ENTER NEW PASSWORD Enter a 4 digit password from the keyboard the display will show the message NEW PASSWORD STORED for two seconds and then revert to the UTILITY menu If any keys other than 0 9 are pressed while entering the password the message ILLEGAL PASSWORD will be shown Using the Password to Access Calibration or Change the Password With the password set pressing calibration onthe UTILITY screen will now show ENTER PASSWORD 70 When the correct password has been entered from the keyboard the display changes to the opening screen of the calibration routine and calibration can proceed as described in the Calibration Routine section If an incorrect password is entered the message INCORRECT PASSWORD is shown for two seconds before the display reverts to the UTILITY menu With the opening screen of the calibration routine displayed after correctly entering the password the password can be changed by pressing password soft key and following the procedure described in Setting the Password If the password is set to 0000 again password protection is removed The password
86. g continues at the next byte in the input stream Bit 4 Execution Error Set when an error is encountered while attempting to execute a completely parsed command The appropriate error number will be reported in the Execution Error Register Bit 3 Not used Bit 2 Query Error Set when a query error occurs The appropriate error number will be reported in the Query Error Register as listed below les Interrupted error 2 Deadlock error Bis Unterminated error 79 80 Bit 1 Bit 0 Not used Operation Complete Set in response to the OPC command Status Byte Register and Service Request Enable Register These two registers are implemented as required by the IEEE std 488 2 Any bits set in the Status Byte Register which correspond to bits set in the Service Request Enable Register will cause the RQS MSS bit to be set in the Status Byte Register thus generating a Service Request on the bus The Status Byte Register is read either by the STB command which will return MSS in bit 6 or by a Serial Poll which will return RQS in bit 6 The Service Request Enable register is set by the SRE lt nrf gt command and read by the SRE command Bit7 Not used Bit6 RQS MSS This bit as defined by IEEE Std 488 2 contains both the Requesting Service message and the Master Status Summary message RQS is returned in response to a Serial Poll and MSS I s returned in response to the STB command Bit5 ESB T
87. gineering units in this case 12 34000 kHz With period selected instead of freq the frequency can be set in terms of a period e g 123 4us can be entered as 0001234 or 123 4e 6 again the display will always show the entry in the most appropriate engineering units Note that the precision of a period entry is restricted to 6 digits 7 digits are displayed but the least significant one is always zero The hardware is programmed in terms of frequency when a period entry is made the synthesised frequency is the nearest equivalent value that the frequency resolution and a 6 digit conversion calculation gives If the frequency is displayed after a period entry the value may differ from the expected value because of these considerations Further once the setting has been displayed as a frequency converting back again to display period will give an exact 6 digit equivalent of the 7 digit frequency but this may differ from the period value originally entered 23 Squarewave generated by Clock Synthesis has 4 digit resolution for both frequency and period entry but the hardware is still programmed in terms of frequency and the same differences may occur in switching the display from period to frequency and back to period Turning the rotary control will increment or decrement the numeric value in steps determined by the position of the edit cursor flashing underline the cursor is moved with the left and right arrowed cursor keys Note t
88. git resolution Variable during sweep The sweep may be free run or triggered from the following sources Manually from keyboard Externally from TRIG IN input or remote interface Sweep can be held and restarted by the HOLD key Any number of channels may be swept simultaneously but the sweep parameters will be the same for all channels Amplitude Offset and Waveform can be set independently for each channel Tone Switching Capability provided for both standard and arbitrary waveforms Arbitrary waveforms are expanded or condensed to exactly 4096 points and DDS techniques are used to allow instantaneous frequency switching Carrier Waveforms Frequency List Trigger Repetition Rate Source Tone Switching Modes Gated Triggered FSK All waveforms except pulse pulse train and sequence Up to 16 frequencies from 1mHz to 10MHz 0 005Hz to 100kHz internal dc to 1MHz external Usable repetition rate and waveform frequency depend on the tone switching mode Internal from keyboard previous channel next channel or trigger generator External from TRIG IN or remote interface The tone is output while the trigger signal is true and stopped at the end of the current waveform cycle while the trigger signal is false The next tone is output when the trigger signal is true again The tone is output when the trigger signal goes true and the next tone is output at the end of the current waveform cycle when the tr
89. h 30 which is 59 points Power On Setting Pressing the power on soft key calls the POWER ON SETTING screen POWER ON SETTING default values restore last setup recall store no 1 The setting loaded can be selected with the appropriate soft key to be default values the default setting restore last setup i e the settings at power down are restored at power up or any of the settings stored in non volatile memories 1 to 9 Default values restores the factory default settings see Appendix 3 System Information The system info soft key calls the SYSTEM INFO screen which shows the instrument name and software revision When system info is pressed a checksum is also made of the firmware EPROM and the result displayed this can be used when a software fault is suspected to check that the EPROM has not got corrupted Calibration Pressing calibration calls the calibration routine see Calibration section Copying Channel Set ups An easy way of copying complete channel set ups waveform frequency amplitude etc is accessed by pressing the COPY CHannel key copy channel 1 to channel 2 execute The top line of the screen shows which channel is currently selected with the channel SETUP keys Pressing the to channel soft key steps the channel number through all the other channels of the instrument Select the channel to be changed and make the copy by pressing the execute soft key 69
90. hannel by pressing the ratio soft key use the rotary knob or cursor keys to set the EXT SUM input attenuation for that channel from 0 to 50dB in 10dB steps This facility permits the same EXT SUM signal to be used at different levels with each channel Clipping will occur if the Sum input level attempts to drive the channel amplitude above the maximum 20Vpp open circuit voltage However the relationship between the EXT SUM input and the maximum summed output depends not only on the Sum input level but also on the channel amplitude setting This is because the Sum input is applied to the amplifier chain prior to the output attenuators the amplifier itself is controlled over a limited range 10dB and the full amplitude range of the channel is achieved by switching in up to five 10dB attenuation stages The summed output cannot exceed the maximum of the range within which the channel output has been set by choice of amplitude setting Whereas with internal Sum the generator gives warnings when the combination of Sum input and amplitude would cause waveform clipping see Internal Sum section it is up to the user to observe the waveforms when using external sum and to make adjustments if the waveform is clipping Note that it is not possible to give a simple guide as to where the range breakpoints are because the use of DC Offset for example changes these points Within each range an EXT SUM signal of 2Vpp will force the chan
91. hannels is allowed e Arb waveforms are created and mostly edited in the non volatile backup memory up to 100 waveforms can be stored subject to the memory limitation of 256k Any of these waveforms can be called into a channel s memory by selecting them to run as an arb or as part of an arb sequence up to the channel s limit of 64k points During editing changes are made to the waveform in non volatile memory and are then copied to all the channels where that waveform is used The exceptions to this are amplitude offset and block copy changes which are initially made only to the waveform copy of the channel currently selected the changes are copied to the non volatile back up memory and then to any other channels using that waveform when the parameter edit is confirmed with the save soft key e A waveform cannot be deleted from a channel s memory if it is running on that channel e Waveforms must be deleted from the channel s memory before they can be deleted from the back up memory e If an arb waveform sequence is running no waveforms can be deleted from that channel whether they are used in the sequence or not e A waveform used by a non active sequence can be deleted but the sequence will not subsequently run properly and should be modified to exclude the deleted waveform The user is reminded of the above constraints by warning error messages in the display when illegal operations are attempted Selecting and Outputting
92. hat the upper frequency limits vary for the different waveform types refer to the Specifications section for details Frequency setting for arbitrary sequence pulse and pulse train is explained in the relevant sections Amplitude AMPLITUDE 20 0 Vpp Vpp Vrms 0 0dBm load hizZ Pressing the AMPL key gives the AMPLITUDE screen The waveform amplitude can be set in terms of peak to peak Volts Vpp r m s Volts Vrms or dBm referenced to a 50Q or 600Q load For Vpp and Vrms the level can be set assuming that the output is open circuit load hiZ or terminated load 50 or load 600Q when dBm is selected termination is always assumed and the load hiZ setting is automatically changed to load 50 Note that the actual generator output impedance is always 50Q the displayed amplitude values for 600Q termination take this into account With the appropriate form of the amplitude selected indicated by the filled diamond the amplitude can be entered directly from the keyboard in integer floating point or exponential format e g 250mV can be entered as 250 or 250 exp 3 etc However the display will always show the entry in the most appropriate engineering units in this case 250mV Turning the rotary control will increment or decrement the numeric value in steps determined by the position of the edit cursor flashing underline the cursor is moved with the left and right arrowed cursor keys Alternate presses of the key
93. he Event Status Bit This bit is set if any bits set in the Standard Event Status Register correspond to bits set in the Standard Event Status Enable Register Bit4 MAV The Message Available Bit This will be set when the instrument has a response message formatted and ready to send to the controller The bit will be cleared after the Response Message Terminator has been sent Bit3 Not used Bit2 Not used Bit1 Not used Bit0 Not used POWER ON COMMAND ERROR EXECUTION ERROR ERROR NUMBER IN EXECUTION ERROR REGISTER EER READ AND CLEAR QUERY ERROR ERROR NUMBER IN QUERY ERROR REGISTER QER READ AND CLEAR OPERATION COMPLETE STANDARD EVENT STATUS REGISTER ESR READ AND CLEAR MS d iad SR E R EAI STANDARD EVENT STATUS ENABLE REGISTER ESE lt NRF gt SET TO lt NRF gt ESE READ STATUS BYTE REGISTER SERIAL POLL READ WITH RQS STB READ WITH MSS SERVICE REQUEST ENABLE REGISTER SRE lt NRF gt SET TO lt NRF gt Status Model D 81 Power on Settings The following instrument status values are set at power on 82 Status Byte Register Service Request Enabl t Standard Event Status Standard Event Stat Register t Execution Error Regis Query Error Register Parallel Poll Enable Register Register us Enable ber Register t 0 0 128
94. he MODE key to get the TONE setup screen TONE type trig 02 000000 kHz 2 3 000000 kHz del Send of list 4 Each frequency in the list can be changed by pressing the appropriate soft key and entering the new value from the keyboard The selected frequency can be deleted from the list by pressing the del delete soft key Additional frequencies can be added to the end of the list by selecting end of list with the appropriate soft key and entering the new frequency from the keyboard The whole list can be scrolled back and forward through the display using the rotary control Tone Type 38 The type soft key onthe TONE setup screen permits three types of tone switching to be specified With type setto trig the frequency changes after each occurrence of the signal edge specified inthe source and slope fieldsonthe TRIGGER IN screen but only after completing the last cycle of the current frequency With type setto gate the frequency changes when the signal specified in the source field goes to the level specified in the slope field onthe TRIGGER IN screen and continues until the level changes again at which point the current cycle is completed the output is then gated off until the next occurrence of the gating signal at which time the next frequency in the list is gated on The difference between triggered and gated tone changes is therefore that in triggered mode the signal changes phase continuously from one frequency to the
95. igger signal goes true again The tone is output when the trigger signal goes true and the next tone is output immediately when the trigger signal goes true again Using 2 channels with their outputs summed together it is possible to generate DTMF test signals Trigger Generator Internal source 0 005 Hz to 100kHz square wave adjustable in 10us steps 3 digit resolution Available for external use from any SYNC OUT socket OUTPUTS Main Output One for each channel Output Impedance Amplitude Amplitude Accuracy Amplitude Flatness DC Offset Range DC Offset Accuracy Resolution 500 5mV to 20Vp p open circuit 2 5mV to 10Vp p into 50Q Amplitude can be specified open circuit hi Z or into an assumed load of 50Q or 6000 in Vpk pk Vrms or dBm 2 1mV at 1kHz into 500 0 2dB to 200 kHz 1dB to 10 MHz 2 5dB to 16 MHz 10V DC offset plus signal peak limited to 10V from 50Q Typically 3 10mV unattenuated 3 digits for both Amplitude and DC Offset Sync Out One for each channel Multifunction output user definable or automatically selected to be any of the following Waveform Sync all waveforms Position Markers Arbitrary only Burst Done Sequence Sync Trigger Sweep Sync Phase Lock Out Output Signal Level Cursor Marker Out A square wave with 50 duty cycle at the main waveform frequency or a pulse coincident with the first few points of an arbitrary waveform Any poi
96. in terms of centr frequency and sweep span about that frequency pressing the start stop soft key on that screen returns the display to the start and stop frequency form of entry Note that when the sweep is displayed in terms of centre frequency and span the span will always be the exact difference between start and stop frequencies but the centre frequency shown will be that of the frequency step nearest the true centre frequency see Principles of Sweep Operation section Sweep Time Pressing the time soft key calls the SWEEP TIME screen SWEEP TIME 0 05 sec steps 100 done 0 The sweep time can be set from 0 03 to 999s with 3 digit resolution by direct keyboard entry or by using the rotary control As explained in the Principles of Sweep Operation section sweeps with a sweep time less than 1 03 seconds will contain less than the maximum 2048 steps because of the minimum 0 5ms dwell at each step For this reason the number of actual steps in the sweep is shown in brackets as a non editable field below the sweep time 29 Sweep Type 30 Pressing the type soft key calls the SWEEP TYPE screen SWEEP TYPE continuous direction up Osync on done This screen is used to set the sweep mode continuous triggered triggered hold and reset manual and sweep direction Successive presses of the direction soft key select one of the following sweep directions up start frequency to stop frequency down st
97. ine in arbitrary waveform lt cpd gt from start address data lt nrf1 gt lt nrf2 gt to stop address data lt nrf3 gt lt nrf4 gt Returns a list of all arbitrary waveforms in backup memory each will return a name and length in the following form lt cpd gt lt nr1 gt Returns a list of all arbitrary waveforms channel memory each will return a name and length in the following form lt cpd gt lt nr1 gt Move the data in arbitrary waveform lt cpd gt from start address lt nrf1 gt to stop address lt nrf2 gt by the offset lt nrf3 gt Set the waveform point at address lt nfr1 gt in arbitrary waveform lt cpd gt to lt nrf2 gt Change the name of arbitrary waveform lt cpd1 gt to lt cpd2 gt Change the size of arbitrary waveform lt cpd gt to lt nrf gt Set beep mode to lt ON gt lt OFF gt lt WARN gt or lt ERROR gt Sound one beep Set the burst count to lt nrf gt Set the arbitrary sample clock freq to lt nrf gt Hz Set the arbitrary sample clock period to lt nrf gt sec Copy the parameters from the current setup chan to channel lt nrf gt Set the dc offset to lt nrf gt Volts Query and clear execution error number register Set the output filter to lt AUTO gt lt EL10 gt lt EL16 gt lt BESS or lt NONE gt Force a trigger to the selected channel Set hold mode lt ON gt lt OFF gt lt ENAB gt or lt DISAB gt Set the channel lock mode to lt INDEP gt lt MASTER gt l
98. ined as character codes OOH to 20H inclusive with the exception of the NL character OAH The high bit of all characters is ignored The commands are case insensitive Command List This section lists all commands and queries implemented in this instrument The commands are listed in alphabetical order within the function groups Note that there are no dependent parameters coupled parameters overlapping commands expression program data elements or compound command program headers each command is completely executed before the next command is started All commands are sequential and the operation complete message is generated immediately after execution in all cases The following nomenclature is used lt rmt gt lt RESPONSE MESSAGE TERMINATOR gt lt cpd gt lt CHARACTER PROGRAM DATA i e a short mnemonic or string such as ON or OFF lt nrf gt A number in any format e g 12 12 00 1 2 e 1 and 120 e 1 are all accepted as the number 12 Any number when received is converted to the required precision consistent with the use then rounded up to obtain the value of the command lt nr1 gt A number with no fractional part i e an integer Any item s enclosed in these brackets are optional parameters If more than one item is enclosed then all or none of the items are required The commands which begin with a are those specified by IEEE Std 488 2 as Common commands All will function when used on the RS232 interface
99. int For arbitrary waveforms the sync marker is a positive pulse coincident with the first few points addresses of the waveform When position pos n marker is selected the instrument generates a pulse marker pattern for arbitrary waveforms The pulse pattern is programmable from the edit waveform menuonthe MODIFY screen When the MAIN OUT waveform is a standard waveform position marker automatically changes to phase zero which is a narrow 1 clock pulse output at the start of each standard waveform cycle Provides a signal during Gate or Trigger modes which is low while the waveform is active at the main output and high at all other times Provides a signal which is low during the last cycle of the last waveform in a sequence and high at all other times Provides a positive going version of the actual trigger signal internal external manual and remote all produce a trigger sync Goes high at the start of the sweep and low at the end of the sweep Produces a positive edge coincident with the start of the current waveform this is used for phase locking instruments This waveform may not appear coherent SYNC OUT logic levels are nominally OV and 5V from typically 50 Q SYNC OUT will withstand a short circuit Do not apply external voltage to this output TRIG IN This is the external input for Trigger Gate Sweep and Sequence operations It is also the input used to synchronise the generator as a slave to another whi
100. io is not close enough to e g 3 1 to maintain phase lock over a period of time the only relationships guaranteed to be realised precisely are 2 1 because the division stages in Clock Synthesis mode are binary A further complication arises with arb waveforms because waveform frequency depends on both waveform size and clock frequency waveform frequency clock frequency waveform size The important relationship with arbs is the ratio of clock frequencies and the above considerations on precision apply to them The most practical use of synchronisation will be to provide outputs at the same frequency or maybe harmonics but with phase differences Connections for Synchronisation The clock connection arrangement is for the rear panel REF CLOCK IN OUT of the master which will be set to phase lock master to be connected directly to the REF CLOCK IN OUT socket of the slave which will be set to phase lock slave Similarly the synchronising connection is from any SYNC OUT of the master which all default to phase lock to the TRIG IN input of the slave Generator Set ups Each generator can have its main parameters set to any value with the exception that the ratio of frequencies between master and slave must be rational and each generator can be set to any waveform but see Synchronising Principles section above Best results will be achieved if the constraints forced on inter channel synchronisation are adopted for inter generator synchr
101. ire range for selected waveform All standard and arbitrary waveforms Double sideband with carrier Double sideband suppressed carrier Internal from the previous channel External from Modulation input socket The external modulation signal may be applied to any number of channels simultaneously DC to gt 100 kHz 0 to 105 1 gt 40dB VCA Approximately 1V pk pk for 100 level change at maximum output SCM Approximately 1Vpk for maximum output Waveform Summing sums the waveform from any channel into the next channel Alternatively any number of channels may be summed with the signal at the SUM input socket Carrier frequency Entire range for selected waveform Carrier waveforms All standard and arbitrary waveforms Sum source Internal from the previous channel External from SUM IN socket Frequency Range DC to gt 8MHz External Signal Range Approximately 5Vpk pk input for 20Vpk pk output Inter channel Phase locking Two or more channels may be phase locked together Each locked channel may be assigned a phase angle relative to the other locked channels Arbitrary waveforms and waveform sequences may be phase locked but certain constraints apply to waveform lengths and clock frequency ratios With one channel assigned as the Master and other channels as Slaves a frequency change on the master will be repeated on each slave thus allowing multi phase waveforms at the same frequency to be easily ge
102. irectly accessing a particular pulse in a long pulse train instead of having to step through the whole sequence Pressing next calls the pulse width screen for the first pulse Pulse 1 width program 25 00 us actual 25 00 us done next The width can be entered directly from the keyboard or by using the rotary control Any value in the range 25 00ns to 99 99s can be programmed but the actual value may differ for this reason the actual pulse width is shown in brackets below the program width The variation between program and actual will only really be noticeable for very short pulse train periods only a few points in the pulse train and very long periods each of the 50 000 points has a long dwell time for exactly the same reasons as described in the Pulse Setup section refer to that section for a detailed explanation Pressing next calls the pulse delay screen for the first pulse Pulse 1 delay program 0 000 ns actual 0 000 ns done next The pulse delay is entered in the same way as pulse width and again the actual delay is shown below the program delay for the same reasons The delay value that can be entered must be in the range pulse train period 1 point positive values delay the pulse with respect to waveform sync from SYNC OUT negative values cause the pulse to be output before the waveform sync Pressing next on this screen calls the first of the 3 screens for setting the parameters of Pulse
103. is 250mVpp exactly and takes account of the small error in the fixed attenuator the offset is 151 mV exactly taking account of the effect of the known attenuation slightly less than the nominal on the set offset of 1 50V Whenever the set DC offset is modified by a change in output level in this way a warning message that this has happened will be displayed Similarly because the DC offset plus signal peak is limited to 10V to avoid waveform clipping a warning message will be displayed if this condition is set This is explained more fully in the Warnings and Error Messages section The output attenuation is controlled intelligently to minimise the difference between the programmed and actual offset when the combination of programmed amplitude and offset allows this Thus when the offset is set to 150mV for example the amplitude can be reduced to nominally 50mVpp before the fixed attenuator causes the actual offset to be different from the programmed value Warnings and Error Messages Two classes of message are displayed on the screen when an illegal combination of parameters is attempted 25 26 WARNING messages are shown when the entered setting causes some change which the user might not necessarily expect Examples are 1 Changing the amplitude from for example 2 5 Volts pk pk to 25mV pk pk brings in the step attenuator if a non zero offset has been set then this will now be attenuated too The message DC OFFSET CHANG
104. is held in EEPROM and will not be lost when the memory battery back up is lost In the event of the password being forgotten contact the manufacturer for help in resetting the instrument Calibration Routine The calibration procedure proper is entered by pressing continue screen pressing exit control fine adjustment Pressing next on the opening Calibration returns the display to the UTILITY menu Pressing tests calls a menu of basic hardware checks used at production test these are largely self explanatory but details can be found in the Service Manual if required At each step the display changes to prompt the user to adjust the rotary control or cursor keys until the reading on the specified instrument is at the value given The cursor keys provide coarse adjustment and the rotary increments the procedure to the next step pressing CE decrements back to the previous step Alternatively pressing exit returns the display to the last CAL screen at which the user can choose to either save new values recall old values or calibrate again The first two displays CAL 00 and CAL 01 specify the connections and adjustment method The next display CAL 02 allows the starting channel to be chosen this allows quick access to any particular channel To calibrate the complete instrument choose the default setting of CH1 The subsequent displays CAL 03 to CAL 55 permit all adjustable parameters to be calibrated The full procedu
105. is the number of waveform points x 25 00ns To achieve faster frequencies up to the specification limit the period must be changed from the pulse setup screen changing the frequency from this screen causes the number of points to be reduced as the period is reduced for period lt 1 25ms Waveform Hold in Pulse and Pulse Train Modes Pulse and Pulse Train waveforms can be paused and re started on any channel by using the front panel MAN HOLD key or a signal applied to the rear panel HOLD IN socket On multi channel instruments the channels which are to be held by the MAN HOLD key or HOLD IN socket must first be enabled using the ARB HOLD INPUT screen accessed by pressing the HOLD KEY ARB HOLD INPUT status no hold mode disabled 55 56 Each channel is selected in turn using the channel SETUP keys and set using the mode soft key the mode changes between disabled and enabled with alternate key presses Pressing the front panel MAN HOLD key stops the waveform at the current level on all enabled channels pressing MAN HOLD a second time restarts the waveform from that level If the ARB HOLD INPUT screen is currently selected the status field will change from no hold to manual hold while the waveform is paused A logic low or switch closure at the rear panel HOLD IN socket also stops the waveform at the currently level on all enabled channels a logic high or switch opening restarts the waveform from that level Ifthe ARB HOLD
106. itrary waveforms already created is stepped through with repeated presses of the wfm soft key or by using the rotary control The criteria for stepping between waveform segments is set by the step on soft key The default setting is step on count which means that the waveform will step on to the next segment after the number of waveform cycles specified in the cnt count field up to 32768 cycles can be set with cnt selected using direct keyboard entries or by rotary control Alternatively the step on criteria can be setto trig edge or trig level inthe step on field trigger edge or trigger level can be mixed with count i e some segments can step on count others on the specified trigger condition but trigger edge cannot be mixed with trigger level in the same sequence If trig edge is selected the sequence starts running at the first waveform segment when sequence is setto run and steps to the following segments in turn at each subsequent trigger The trigger source can be any of the settings selected on the TRIGGER IN setup screen called by the TRIG IN key these are described fully in the Triggered Burst and Gate section At each trigger the current waveform cycle plus one further whole cycle are completed before the waveform of the next segment is started If trig level is selected the sequence runs continuously through each segment in turn 1 cycle per segment while the trigger level is true When the trigger level goes false the wavefo
107. ive edged version of the external trigger or gate signal when external triggering or gating is specified 33 Adjacent Channel Trigger Output On multi channel instruments the Trigger Out signal of an adjacent channel can be used as the control signal for a Triggered Burst The channel numbering wraps round i e channels 1 and 3 are obviously adjacent to channel 2 but so are channels 2 and 4 adjacent to channel 1 The source of the Trigger Out signal is selected by the source soft key on the TRIGGER OUT screen called by the TRIG IN key TRIGGER OUT A v mode auto source wfm end The Trigger Out choices are as follows wfm end Waveform end a positive going pulse coincident with the end of a waveform cycle and the start of the next pos n marker Position marker arbitrary waveforms only Any point s on the main waveform may have marker bit s set high or low No output if selected for a standard waveform seq sync Sequence sync a positive going pulse coincident with the end of a waveform sequence burst done A positive going pulse coincident with the end of the last cycle of a burst The default choice is wfm end except when the channel is running a sequence in which case it becomes seq sync To set the Trigger Out to anything other than its default it is necessary to change the mode from auto to manual using the mode soft key Trigger Out is an internal signal but as with the other trigger sourc
108. ive voltage This DC level can now be modulated by the signal applied to the EXT MODULATION input External SCM Select scM withthe type soft key onthe MODULATION screen Connect the modulating signal to the EXT MODULATION input nominally 1kQ input impedance With no signal the carrier is fully suppressed a positive or negative level change at the modulation input increases the amplitude of the carrier Note that clipping will occur if the SCM signal attempts to drive the output above the 20Vpp open circuit voltage Peak modulation i e maximum carrier amplitude 20Vpp is achieved with an external SCM level of approximately 1V i e a 2Vpp signal Modulation frequency range is DC to 100kHz When external SCM is selected for a channel the amplitude control of that channel is disabled the AMPLITUDE setup screen shows the message fixed by SCM Internal Modulation 58 Pressing the MODULATION key calls the MODULATION setup screen MODULATION source ext 0 type VCA The source soft key steps the modulation choice between off externaland CHx where x isthe number of the previous channel CHx is the source for internal modulation Note that channel 1 and single channel instruments do not have a previous channel i e they have no internal modulation capability refer to the Inter Channel Block Diagram With CHx selected the modulation mode can be switched between AM and scM M with alternate presses of the type soft key When
109. l arbitrary waveforms are expanded or condensed in software to 4096 points when Sweep is turned on This does not affect the original data Sweep mode is turned on and off either by the on or off soft key onthe SWEEP SETUP screen accessed by pressing the SWEEP front panel key or by the sweep soft key on the MODE screen In multi channel instruments two or more channels can be swept at once but the sweep parameters are the same for all channels When sweep is turned on the software creates a table of 2048 frequencies between and including the specified start and stop values For sweep times of 1 03s and greater the sweep will step through all 2048 frequency values Below 1 03s however the frequency sweep will contain fewer steps because of the minimum 0 5ms dwell at each step at the shortest sweep time 30ms the sweep will contain only 60 steps Because any frequency used in sweep mode must be one of the tabled values the centre frequency displayed see Sweep Range may not be the exact mid point and markers see Sweep Marker may not be exactly at the programmed frequency The frequency resolution of the steps will be particularly coarse with wide sweeps at the fastest sweep rate Connections for Sweep Operation Sync Out and Trig In 28 Sweeps are generally used with an oscilloscope or hard copy device to investigate the frequency response of a circuit The MAIN OUT is connected to the circuit input and the circuit output is connected to
110. me baud rate and all must be powered on otherwise instruments further down the daisy chain will not receive any data or commands The other parameters are fixed as follows Start Bits 1 Parity None Data Bits 8 Stop Bits 1 RS232 Character Set Because of the need for XON XOFF handshake it is possible to send ASCII coded data only binary blocks are not allowed Bit 7 of ASCII codes is ignored i e assumed to be low No distinction is made between upper and lower case characters in command mnemonics and they may be freely mixed The ASCII codes below 20H space are reserved for addressable RS232 interface control In this manual 20H etc means 20 in hexadecimal Addressable RS232 Interface Control Codes 76 All instruments intended for use on the addressable RS232 bus use the following set of interface control codes Codes between 00H and 1FH which are not listed here as having a particular meaning are reserved for future use and will be ignored Mixing interface control codes inside instrument commands is not allowed except as stated below for CR and LF codes and XON and XOFF codes When an instrument is first powered on it will automatically enter the Non Addressable mode In this mode the instrument is not addressable and will not respond to any address commands This allows the instrument to function as a normal RS232 controllable device This mode may be locked by sending the Lock Non Addressable mode control code 04H The cont
111. mode The programmed mod depth cannot be set Numeric value too large switching to sample period Error Messages 10 1 Frequency out of range for the selected waveform 102 Sample clock frequency required exceeds 40MHz 10 10 10 10 10 10 10 3 Sample clock frequency required is less than 0 1Hz 4 Pulse pulse train period out of range for current set up 5 Pulse width cannot be greater than the period 6 Absolute value of pulse delay must be lt period 7 Pulse width cannot be less than 25ns 8 Maximum output level exceeded 9 Minimum output level exceeded 110 Minimum dc offset value exceeded 111 Maximum dc offset value exceeded 112 The value entered is out of range 115 There are no arb waveforms defined Use WAVEFORM CREATE 116 Cannot delete arb while it is selected for any output chan 117 Arb name exists names must be unique 118 Arb waveform length exceeds available memory 119 Arb waveform length cannot be less than four points 12 12 12 12 12 12 1 Start address error must be in the range 0 lt n lt stop addr 2 Stop address error must be in the range strt lt n lt wfm len 5 No GPIB available 7 System ram error check battery 8 Point value error must be in the range 2048 lt n lt 2047 9 Wave offset error must be in the range 4096 lt n lt 4095 97 98 131 132 133 134 135 136 138 139 140 141 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158
112. modulation source e g channel 2 can be summed into Channel 3 internal Sum is not available on channel 1 or on a single channel instrument Summing shares some of the generator s inter channel resources with Modulation modes as a result neither internal nor external Sum can be used with internal modulation but external modulation is possible To better understand the constraints the following sections and the Modulation chapter should be read with reference to the fold out block diagrams at the end of the manual which show the control signals of a single channel and the inter channel connections These diagrams also show the inter channel trigger connections described in the Triggered Burst and Gate chapter in general inter channel triggering is possible simultaneously with summing External Sum 60 In Sum mode an external signal applied to the EXT SUM input is summed with the waveform s on the specified channel s The same Sum input signal can be used at different amplitudes with each of the channels with which it is summed Pressing the SUM key calls the SUM set up screen SUM source ext gt Oratio 0dB 0CH2 2 00 Vpp Pressing the source soft key steps the Sum sources between off external and CHx where x is the number of the previous channel refer to the Inter Channel Block Diagram With ext selected the screen is as shown above The level of the EXT SUM can be adjusted independently for the selected c
113. move to the next step While in remote calibration mode very little error checking is performed and it is the controllers responsibility to ensure that everything progresses in an orderly way Only the following commands should be used during calibration WARNING Using any other commands while in calibration mode may give unpredictable results and could cause the instrument to lock up requiring the power to be cycled to regain control 72 Adjust for 0 1V 1mV Adjust for 2 236V AC 10mV Adjust for OV 5mV Adjust for 5V 5mV Adjust for 10V 10mV Adjust for OV 5mV Adjust for 10V 10mV Check for 10V 3 Adjust for minimum Volts AC Adjust for OV 5mV Adjust for OV 5mV Adjust for 10V 10mV Adjust for 1V 1mV Adjust for 0 1V 1mV Adjust for 2 236V AC 10mV Adjust for OV 5mV Adjust for 5V 5mV Adjust for 10V 10mV Adjust for OV 5mV Adjust for 10V 10mV Check for 10V 3 Adjust for minimum Volts AC Adjust for OV 5mV Adjust for OV 5mV Adjust for 10V 10mV Adjust for 1V 1mV Adjust for 0 1V 1mV Adjust for 2 236V AC 10mV Adjust for OV 5mV Adjust for 5V 5mV Adjust for 10V 10mV Adjust for 10 00000 MHz at SYNC OUT CALIBRATION lt cpd gt nrf The calibration control command lt cpd gt can be one of three START SAVE ABORT CALADJ lt nrf gt CALSTEP sub commands Enter calibration mode this command must be issued before any
114. n AMPLITUDE 001 00 start 00400 stop 01000 undo exit save The waveform amplitude can be changed on a section of the waveform defined by the start and stop addresses Set the addresses by pressing the appropriate soft key and making entries directly from the keyboard or by rotary control 46 The data values over the specified section of the waveform can be multiplied by a factor of between 0 01 and 100 0 by making entries in the AMPLITUDE field Press the appropriate soft key and make entries direct from the keyboard or by using the rotary control the amplitude changes on completion of the entry Note that entries gt 1 0 will cause clipping if the waveform already uses the full 2048 to 2047 data value range the result is however still treated as a valid waveform The original waveform can be restored by pressing the undo soft key Amplitude edit operates on the version of the waveform in the channel currently selected by the channel SETUP keys the effect of the edit can be seen by selecting the waveform to run on that channel When the amplitude has been modified as required the new waveform can be saved by pressing the save key the action of saving modifies the waveform in the backup memory and then any other copies of the waveform in other channel memories Once saved the original waveform cannot be recovered Pressing exit returns tothe EDIT FUNCTIONS screen without change Waveform Offset Pressing the wave offset
115. n Remote Commands Remote Command Summary Maintenance Appendix 1 Warning and Error Messages Appendix 2 SYNC OUT Automatic Settings Appendix 3 Factory System Defaults Appendix 4 Waveform Creation Software Block Diagrams Front Panel Diagrams 57 57 57 58 60 62 65 67 70 74 83 92 96 97 100 101 102 102 103 Overview This manual describes the features and operation of 1 2 and 4 channel arbitrary waveform generators The physical differences between the 2 and 4 channel generators are straightforward the 2 channel instrument has no set up keys or output connections for channels 3 and 4 The single channel instrument has essentially the same keys but they are arranged quite differently to suit the 2 rack case The fold out diagram at the end of the manual shows all 3 models The set up and operation of an individual channel in any of the instruments is identical and therefore no distinction is made between the different models when describing the functions associated with any single channel Those features associated with multi channel operation inter channel summing phase locking etc self evidently apply only to the multi channel instruments the relevant chapters are mostly grouped together towards the end of the manual but before Remote Operation although some mention of multi channel operation is made when appropriate in earlier sections To avoid repetition specific reference is not always made to 2 an
116. nel output from range minimum to range maximum if the channel amplitude is set to mid range the EXT SUM signal needed to force the output to range maximum is about half i e 1Vpp To facilitate the setting of appropriate Sum and amplitude levels the output amplitude of the selected channel can also be changed from the SUM set up screen Press the CHx soft key and adjust the amplitude with direct keyboard entries or by using the rotary knob External Sum cannot be used with internal modulation Internal Sum Pressing the SUM key calls the SUM set up screen SUM source CH1 Oratio 1 00000 0CH2 2 00 Vpp 0CH1 2 00 Vpp Pressing the source soft key steps the Sum source between off externaland CHx where x is the number of the previous channel CHx is the source of the internal Sum signal Note that channel 1 and single channel instruments do not have a previous channel refer to the Inter Channel Block Diagram With CHx selected for internal Sum the screen is as shown above The amplitude of both the summing channel CHx 1 and the internal Sum signal CHx are shown in the display together with the ratio between them All three parameters can be selected with the appropriate soft key and set directly from the keyboard or by the rotary control Changing any one parameter will also adjust the interdependent one e g adjusting the amplitude of either channel will cause the displayed ratio to change Note that the value
117. nerated DDS waveforms are those with 7 digits of frequency setting resolution while Non DDS waveforms have 4 digits 10 Phase Resolution DDS waveforms Non DDS waveforms Phase Error All waveforms degree 0 1 0 1 degree or 360 degrees number of points whichever is the greater lt 10ns The signals from the REF IN OUT socket and the SYNC OUT socket can be used to phase lock two instruments where more than 4 channels are required Inter channel Triggering Any channel can be triggered by the previous or next channel The previous next connections can be used to daisy chain a trigger signal from a start channel through a number of channels in the chain to an end channel Each channel receives the trigger out signal from the previous or next channel and drives its selected trigger out to the next or previous channel The end channel trigger out can be set up to drive the start channel closing the loop In this way complex and versatile inter channel trigger schemes may be set up Each channel can have its trigger out and its output waveform set up independently Trigger out may be selected from Waveform End Position Markers Sequence Sync or Burst Done Using the scheme above it is possible to create a sequence of up to 64 waveform segments each channel producing up to 16 segments and all channels being summed to produce the complete waveform at the output of channel 4
118. ng and set up copying can be set e The SETUP keys multi channel instruments only select the channel to be edited the lamp lights beside the channel currently enabled for editing e Eight soft keys around the display are used to directly set or select parameters from the currently displayed menu their operation is described in more detail in the next section e The STATUS key always returns the display to the default start up screen which gives an overview of the generators status Pressing STATUS again returns the display to the previous screen Further explanations will be found in the detailed descriptions of the generator s operation Principles of Editing 20 Each screen called up by pressing a front panel key shows parameter value s and or a list of choices Parameter values can be edited by using the ROTARY CONTROL in combination with the left and right arrowed CURSOR keys or by direct numeric keyboard entry choices are made using the soft key associated with the screen item to be selected The examples which follow assume factory default settings The channel to be edited must first be selected by pressing the appropriate SETUP key the lamp lights beside the SETUP key of the channel currently enabled for editing A diamond beside a screen item indicates that it is selectable hollow diamonds identify deselected items and filled diamonds denote selected items For example press MODE to get the screen shown below MODE
119. nt s on the waveform may have associated marker bit s set high or low Produces a pulse coincident with the last cycle of a burst Produces a pulse coincident with the end of a waveform sequence Selects the current trigger signal Useful for synchronizing burst or gated signals Outputs a pulse at the start of sweep to synchronize an oscilloscope or recorder Used to phase lock two generators Produces a positive edge at the 0 phase point TTL CMOS logic levels from typically 50Q Adjustable output pulse for use as a marker in sweep mode or as a cursor in arbitrary waveform editing mode Can be used to modulate the Z axis of an oscilloscope or be displayed on a second scope channel Output Signal Level Output Impedance INPUTS Trig In Frequency Range Signal Range Minimum Pulse Width Polarity Input Impedance Modulation In Frequency Range Signal Range Input Impedance Sum In Frequency Range Signal Range Input Impedance Hold Adjustable from nominally 2V to 14V normal or inverted adjustable width as a cursor 600Q typical DC 1MHz Threshold nominally TTL level maximum input 10V 50ns for Trigger and Gate modes 50us for Sweep mode Selectable as high rising edge or low falling edge 10kQ DC 100kHz VCA Approximately 1V pk pk for 100 level change at maximum output SCM Approximately 1Vpk for maximum output Typically 1 kQ DC 8 MHz Approximately 2
120. nthesised waveforms will not reliably lock to other Clock Synthesised waveforms e Pulse and Pulse train waveforms will lock to other Pulse and Pulse trains and each other but should be built with equal periods e Arb waveforms should be the same length although this is not forced and does not create an error message Synchronising Two Generators Two generators can be synchronised together following the procedure outlined below It is possible to link more than two generators in this way but results are not guaranteed Synchronising Principles Frequency locking is achieved by using the clock output from the master generator to drive the clock inputs of a slave The additional connection of an initialising SYNC signal permits the slave to be synchronised such that the phase relationship between master and slave outputs is that specified on the slave generator s Inter channel set up screen Synchronisation is only possible between generators when the ratio of the master and slave frequencies is rational e g 3kHz can be synchronised with 2kHz but not with 7kHz Special considerations arise with waveforms generated by Clock Synthesis mode squarewave arbitrary pulse pulse train and sequence because of the relatively poor precision with which the frequency is actually derived in the hardware With these waveforms frequencies with an apparently rational relationship e g 3 1 may be individually synthesised such that the rat
121. o 000 0000 Hz without losing the 100 Hz increment Turning the control quickly will step numeric values in multiple increments Principles of Operation The instrument operates in one of two different modes depending on the waveform selected DDS mode is used for sine cosine haversine triangle sinx x and ramp waveforms Clock Synthesis mode is used for square pulse pulse train arbitrary and sequence In both modes the waveform data is stored in RAM As the RAM address is incremented the values are output sequentially to a Digital to Analogue Converter DAC which reconstructs the waveform as a series of voltages steps which are subsequently filtered before being passed to the main output connector 16 Bit 12 Bit DATA MAIN O P RAM ADDRESS The main difference between DDS and Clock Synthesis modes is the way in which the addresses are generated for the RAM and the length of the waveform data 21 Clock Synthesis Mode In Clock Synthesis mode the addresses are always sequential an increment of one and the clock rate is adjusted by the user in the range 40MHz to 0 1Hz The frequency of the waveform is clock frequency waveform length thus allowing short waveforms to be played out at higher repetition rates than long waveforms e g the maximum frequency of a 4 point waveform is 40e6 4 or 10MHz but a 1000 point waveform has a maximum frequency of 40e6 1000 or 40kHz 16 Bits RAM ADDRESS CLOCK 0 1H
122. olls through all the alphanumeric characters in sequence The name can be up to 8 characters long 43 Return to the MODIFY screen by pressing rename which implements the new name or cancel Waveform Info Pressing the info soft key onthe MODIFY screen calls the info screen Info wv03 exit length 00128 chan 3 4 seq The screen gives the name of the waveform its length and the channels and sequences where it is used the where used information is particularly useful when executing waveform management operations such as delete Pressing exit returns the display to the MODIFY screen To view what waveforms are held in a particular channel memory select the channel with its SETUP key press the UTILITY key to view the UTILITY MENU and then press the chan wfm info soft key to get the CHAN WFM INFO screen CHANNEL WEM INFO waveforms 1 free mem 65436 exit This shows the number of waveforms and the free memory on that channel Press the exit soft key to return to the UTILITY MENU Delete Waveform Pressing the delete soft key displays a request for confirmation that the selected waveform is to be deleted from the backup memory Delete waveform wv01 a cancel delete 0 Confirm deletion by pressing the delete soft key which will return the display to the MODIFY screen with the next arb waveform automatically selected cancel aborts the deletion Waveforms cannot be deleted from the backup m
123. on any of these edit screens will return the display to the EDIT FUNCTIONS menu Point Edit Press the point edit softkey to call the POINT EDIT screen POINT EDIT addrs value e 00512 0500 exit next point To modify a point press the addrs_ soft key and enter the address directly from the keyboard or by using the rotary control the current data value will be displayed to the right of the address To change the value press value and enter the new value directly from keyboard or by using the rotary control Changing the data value automatically updates the waveform Pressing the next point soft key automatically advances the address by one point alternatively press addrs to re select address and permit entries from the keyboard or by rotary control Line Edit Press the line draw soft key to call the LINE screen LINE addrs value frm 00512 0500 oto 00750 0412 exit draw line The display shows a frm from and to address which will be the points between which a straight line will be created when the draw line soft key is pressed The default frm address is the first point on the waveform or the point most recently edited if point edit has been used Set the from address and value by pressing the appropriate soft key and making an entry direct from the keyboard or by using the rotary control repeat for the to address and value The line will be drawn between the two selected poin
124. onisation The master has its CLOCK IN OUT set to phase lock master onthe REF CLOCK I O SETUP menu called by the ref clock i o soft key on the UTILITY screen see System Operations section REF CLOCK I O SETUP input output phase lock slave Repeated presses of the phase lock soft key toggle between master and slave The slave is setto slave Setting the slave generator to phase lock slave forces the slave s mode to continuous and defaults all the SYNC OUT outputs to phase lock Only one of the SYNC OUTs is needed for inter generator synchronisation the others may be reset to other functions if required The phase relationship between the slave and the master is set on the Inter channel set up screen of the slave accessed by pressing the INTERCHannel key 65 mode indep Ophase 000 0 actual 000 0 status off view The phase of the slave generator is set by adjusting the phase of the master channel on the slave generator s Inter channel set up screen exactly as described in the Phase setting between Channels section of the inter channel Synchronisation chapter The phase s of slave channel s on the slave generator are set up with respect to the master in the way described in that same section When a single generator which has no Inter channel set up key or screen is the slave its phase is set on the TRIGGER GATE SETUP screen see Trigger Phase section of the Triggered Burst and Gate chapter The con
125. op frequency to start frequency up down start frequency to stop frequency and back to start frequency down up stop frequency to start frequency and back to stop frequency The total sweep time is always that set on the SWEEP TIME screen i e for up down and down up operation the sweep time in each direction is half the total Similarly the total number of steps is the same for all choices i e there will be half the number of steps in each direction for up down and down up operation In the sweep mode descriptions which follow the direction is assumed to be up but all modes can be used with all sweep directions In continuous mode the generator sweeps continuously between the start and stop frequencies triggered repetitively by an internal trigger generator whose frequency is determined by the sweep time setting At the stop frequency the generator resets to the start frequency after a delay long enough for an oscilloscope to retrace for example and begins a new sweep If sync issetto on the default the generator actually steps from the stop frequency to zero frequency and then starts the next sweep from the first point of the waveform synchronised to the internally generated trigger signal This is useful because the sweep always starts from the same point in the waveform but the waveform discontinuity can be undesirable in some circumstances e g filter evaluation With sync setto off the frequency steps directly and phase continuously from
126. or lt DBM gt Set the output load which the generator is to assume for amplitude and dc offset entries to lt 50 gt 509 lt 600 gt 600Q or lt OPEN gt Set the dc offset to lt nrf gt Volts Select the output waveform as lt SINE gt lt SQUARE gt lt TRIANG gt lt DC gt lt POSRMP gt lt NEGRMP gt lt COSINE gt lt HAVSIN gt lt HAVCOS gt lt SINC gt lt PULSE gt lt PULSTRN gt lt ARB gt or lt SEQ gt Set the pulse period to lt nrf gt sec Set the pulse width to lt nrf gt sec Set the pulse delay to lt nrf gt sec Set the number of pulses in the pulse train to lt nrf gt Set the pulse train period to lt nrf gt sec Set the pulse train base line to lt nrf gt Volts Set the level of pulse train pulse number lt nrf1 gt to lt nrf2 gt Volts Set the width of pulse train pulse number lt nrf1 gt to lt nrf2 gt sec Set the delay of pulse train pulse number lt nrf1 gt to lt nrf2 gt sec Makes the pulse train and runs it similar to the WAVE PULSTRN command Select an arbitrary waveform for output lt cpd gt must be the name of an existing arbitrary waveform Backup memory is always used as the source of the arb The arb will be copied to the channel memory if necessary Returns a list of all arbitrary waveforms in the channel s memory each will return a name and length in the following form lt cpd gt lt nr1 gt The list will end with lt rmt gt Returns a
127. other modes In screens with lists of items that can be selected i e items marked with a diamond the cursor keys and rotary control are used to scroll all items through the display if the list has more than three items look for example at the STD standard waveform and UTILITY screens In screens where a parameter with a numeric value is displayed the cursor keys move the edit cursor a flashing underline through the numeric field and the rotary control will increment or decrement the value the step size is determined by the position of the edit cursor within the numeric field Thus for STANDARD FREQUENCY setto 1 00000 MHz rotating the control will change the frequency in 1kHz steps The display will auto range up or down as the frequency is changed provided that autoranging permits the increment size to be maintained this will in turn determine the lowest or highest setting that can be achieved by turning the control In the example above the lowest frequency that can be set by rotating the control is 1 KHz shown on the display as 1 000000 kHz This is the limit because to show a lower frequency the display would need to autorange below 1kHz to xxx xxx Hz in which the most significant digit represents 100HZ i e the 1kHz increment would be lost If however the starting frequency had been set to 1 000000 MHz i e a 100 Hz increment the display would have autoranged at 1kHz to 900 0000 Hz and could then be decremented further right down t
128. pened for any adjustment replacement maintenance or repair Any adjustment maintenance and repair of the opened instrument under voltage shall be avoided as far as possible and if inevitable shall be carried out only by a skilled person who is aware of the hazard involved If the instrument is clearly defective has been subject to mechanical damage excessive moisture or chemical corrosion the safety protection may be impaired and the apparatus should be withdrawn from use and returned for checking and repair Make sure that only fuses with the required rated current and of the specified type are used for replacement The use of makeshift fuses and the short circuiting of fuse holders is prohibited This instrument uses a Lithium button cell for non volatile memory battery back up typical life is 5 years In the event of replacement becoming necessary replace only with a cell of the correct type i e 3V Li Mn02 20mm button cell type 2032 Exhausted cells must be disposed of carefully in accordance with local regulations do not cut open incinerate expose to temperatures above 60 C or attempt to recharge Do not wet the instrument when cleaning it and in particular use only a soft dry cloth to clean the LCD window The following symbols are used on the instrument and in this manual Caution refer to the accompanying documentation incorrect operation may damage the instrument terminal connected to chassis ground mains supply OF
129. points in the waveform the setting resolution is however much better than 25 00ns because the time per point is adjusted as well as the number of points since the pulse width and delay are also defined in terms of the same point time varying the time per point affects their resolution For example if the period is set to 500ns the minimum pulse width when set to 25 00ns will actually be 25 00ns 20 points at 25 00ns each exactly define the 500ns period However if the period is set to 499 Ons 20 points at the minimum point time of 25 00ns will be too long so 19 points are used and the point time is adjusted to 26 26ns 499 0 19 26 26ns is now the increment size used when changing the pulse width and delay For periods above 1 25ms the maximum number of points in the waveform 50 000 becomes the factor determining pulse width and delay resolution For example with the period set to 100ms the smallest pulse width and delay increment is 2us 100ms 50 000 This may appear to cause significant errors at extreme settings e g setting 100ns in the above example will still give an actual width of 2us but in practical terms a 1 in 50 000 resolution 0 002 is quite acceptable Pulse period can be adjusted irrespective of the pulse width and delay setting e g can be set smaller than the programmed pulse width because unlike a conventional pulse generator pulse width and delay are adjusted proportionally as the period is changed
130. possible within level constraints SUM and internal MOD cannot be active together Modulation depth or SCM level is out of range This channel s waveform ram is full SUM or Modulation conflict Inter channel lock not possible Lock status is off This error may occur for several reasons In each case there is a conflict of the phase locking settings In most cases the status of the phase lock is set to off Any of the following conditions will cause this error 1 More than one master channel is enabled 2 No master channel is enabled 3 The locked channels contain a mixture of DDS and PLL generated waveforms 4 Frequency tracking is enabled mode master freq but the frequencies are not the same on all channels If PLL waveforms are locked the mode will be forced to frequency tracking A locked channel is not set to continuous mode 6 An attempt is made to turn on phase lock with a frequency set too high Note that the maximum frequency for phase locked DDS operation is 10MHz 7 An attempt is made to set the frequency too high during phase lock This error does not set phase lock to off the system simply inhibits the setting of the incorrect frequency a Remote Warnings 72 Length is different to that in the ARBDEF CSV command Remote Errors 120 126 162 163 164 165 166 167 168 169 170 171 173 174 175 176 177 185 Waveform limit value out of range Illegal store number requested Byte value outside
131. r gated waveform modes The automatic selection will be mentioned in each of the appropriate main waveform mode sections and a full table is given in Appendix 2 The automatic selection can still be changed manually by the sre soft key even when auto mode has been selected but the selection will immediately revert to the automatic choice as soon as any relevant parameter e g main waveform frequency or amplitude is adjusted Manual must be selected by the mode soft key for a source other than the automatic choice to remain set The auto selection will generally set the most frequently used signal e g waveform sync for all continuous main waveforms but manual will need to be used for special requirements e g position markers on arbitrary waveforms 27 Sweep Operation General Principles of Sweep Operation All standard and arbitrary waveforms can be swept with the exception of pulse pulse train and sequence During Sweep all waveforms are generated in DDS mode because this offers the significant advantage of phase continuous sweeps over a very wide frequency range up to 1019 However it must be remembered that the frequency is actually stepped not truly linearly swept and thought needs to be given as to what the instrument is actually doing when using extreme combinations of sweep range and time For DDS operation during Sweep all waveforms must be 4096 points in length this is the natural length for standard waveforms but al
132. re is as follows CAL 03 CAL 04 CAL 05 CAL 06 CAL 07 CAL 08 CAL 09 CAL 10 CAL 11 CAL 12 CAL 13 CAL 14 CAL 15 CAL 16 CAL 17 CAL 18 CAL 19 CAL 20 CAL 21 CAL 22 CAL 23 CH1 CH1 CH1 CH1 CH1 CH1 CH1 CH1 CH1 CH1 CH1 CH1 CH1 CH2 CH2 CH2 CH2 CH2 CH2 CH2 CH2 DC offset zero DC offset at full scale DC offset at full scale Multiplier zero Multiplier offset Waveform offset Output level at full scale 20dB attenuator 40dB attenuator 10dB attenuator Not used Not used Not used DC offset zero DC offset at full scale DC offset at full scale Multiplier zero Multiplier offset Waveform offset Output level at full scale 20dB attenuator Adjust for OV 5mV Adjust for 10V 10mV Check for 10V 3 Adjust for minimum Volts AC Adjust for OV 5mV Adjust for OV 5mV Adjust for 10V 10mV Adjust for 1V 1mV Adjust for 0 1V 1mV Adjust for 2 236V AC 10mV Adjust for OV 5mV Adjust for 10V 10mV Check for 10V 3 Adjust for minimum Volts AC Adjust for OV 5mV Adjust for OV 5mV Adjust for 10V 10mV Adjust for 1V 1mV 71 CAL 24 CAL 25 CAL 26 CAL 27 CAL 28 CAL 29 CAL 30 CAL 31 CAL 32 CAL 33 CAL 34 CAL 35 CAL 36 CAL 37 CAL 38 CAL 39 CAL 40 CAL 41 CAL 42 CAL 43 CAL 44 CAL 45 CAL 46 CAL 47 CAL 48 CAL 49 CAL 50 CAL 51 CAL 52 CAL 53 CAL 54 CAL 55 CH2 CH2 CH2 CH2 CH2 CH3 CH3
133. re last setup onthe POWER ON SETTING screen the waveforms will be restored to the channel s memory at power on see System Operations chapter The same arbitrary waveform can be selected to run on more than one channel and when it is edited in backup memory the changes will be made to all copies of the waveform too The following sections give full details as to how arbitrary waveforms are created and modified 41 Creating New Waveforms Pressing the CREATE key calls the CREATE NEW WAVEFORM screen CREATE NEW WAVEFORM free memory 258972 create blank create from copy Create Blank Waveform Pressing the create blank soft key calls the menu create wv00 Osize 01024 cancel create 0 The top line contains the user defined waveform name which can be 8 characters long The instrument allocates a default name of wv n starting at wv00 the name can be edited by selecting the appropriate character position with the cursor keys and then setting the character with the rotary control which scrolls through all alphanumeric characters in sequence Pressing the size soft key permits the waveform length to be entered directly from the keyboard or by using the rotary control and cursor keys the default size is 1024 The minimum size is 4 and the maximum 65536 appropriate warnings are given if attempts are made to set a waveform size less than 4 or greater than the remaining available backup memory The waveform
134. responses The interface code ODH CR may be used as required to aid the formatting of commands it will be ignored by all instruments Most instruments will terminate responses with CR followed by LF The interface code 13H XOFF may be sent at any time by a listener instrument or controller to suspend the output of a talker The listener must send 11H XON before the talker will resume sending This is the only form of handshake control supported by the addressable RS232 mode Full List of Addressable RS232 Interface Control Codes 02H Set Addressable Mode 03H Universal Unaddress control code 04H Lock Non Addressable mode control code 06H Acknowledge that listen address received OAH Line Feed LF used as the universal command and response terminator ODH Carriage Return CR formatting code otherwise ignored 11H Restart transmission XON 12H Listen Address must be followed by an address belonging to the required instrument 13H Stop transmission XOFF 14H Talk Address must be followed by an address belonging to the required instrument 18H Universal Device Clear 77 GPIB Interface The 24 way GPIB connector is located on the instrument rear panel The pin connections are as specified in IEEE Std 488 1 1987 and the instrument complies with IEEE Std 488 1 1987 and IEEE Std 488 2 1987 GPIB Subsets This instrument contains the following IEEE 488 1 subsets Source Handshake SH1 Accep
135. rker Frequency Direction Spacing Sweep Time Type Filter Sync Out Sequence Status Wm Step ON Count Arbitrary Sine 10kHz 2 0Vpp Output Off OV HiZ Internal ims Positive 1 Odeg Off AM VCA 30 Off 100kHz 10MHz 5MHz Up Log 50ms Continuous Auto Auto all segments set as follows Off except seg 1 First arb Count 1 All unaffected by reset or RST or by the remote command RST All channels will be receive the 101 Appendix 4 Waveform Manager Plus Arbitrary Waveform Creation and Management Software 102 The Thurlby Thandar Waveform Manager Plus program allows construction editing exchange translation and storage of many types of waveform data It is compatible with many popular DSOs and all TTi waveform generation products Waveforms may be generated by equation entry freehand drawing combining existing waveforms or any combinations of these methods Data upload and download are possible via RS232 COM1 4 or GPIB subject to a compatible GPIB card being correctly installed and configured in your PC Both upload and download of waveform data are possible and where applicable data exchange via 3 5 in floppy disks in the Tektronix ISF format is available Text data may be read from the Windows clipboard and used to create a waveform The text data format is very free and will allow most lists of numbers with or without intervening text to be read as wave
136. rm currently selected runs continuously until the level goes true again at which point the sequence runs continuously through each segment in turn again The trigger level source can be any of the settings selected on the TRIGGER IN setup screen with the exception of the MAN TRIG key which can only produce an edge not a level when pressed Providing the step on fieldis setto count forall segments the waveform sequence can also be run in Gated and Triggered Burst modes in the same way as simple waveforms refer to the Triggered Burst and Gated section for full details The individual segments of the sequence can be turned on or off with the on off soft key Note that turning a segment off will automatically set all subsequent segments off turning a segment on will also turn on any others between segment 1 and itself that were previously off Segment 1 is always on When the whole sequence is defined the set up is constructed by pressing the done soft key which returns the display to the initial SEQUENCE screen The sequence can be run and stopped from this screen with the run and stop soft keys respectively Frequency and Amplitude Control with Arbitrary Waveforms Frequency and Amplitude control work in essentially the same way as for standard waveforms with the following minor differences 49 Frequency Pressing the FREQuency key with an arbitrary waveform selected calls the ARBITRARY FREQUENCY screen ARBITRARY FREQUENCY 40 00 M
137. roller and instrument can now freely use all 8 bit codes and binary blocks but all interface control codes are ignored To return to addressable mode the instrument must be powered off To enable addressable mode after an instrument has been powered on the Set Addressable Mode control code 02H must be sent This will then enable all instruments connected to the addressable RS232 bus to respond to all interface control codes To return to Non Addressable mode the Lock Non Addressable mode control code must be sent which will disable addressable mode until the instruments are powered off Before an instrument is sent a command it must be addressed to listen by sending the Listen Address control code 12H followed by a single character which has the lower 5 bits corresponding to the unique address of the required instrument e g the codes A Z or a z give the addresses 1 26 inclusive while is address 0 and so on Once addressed to listen the instrument will read and act upon any commands sent until the listen mode is cancelled Because of the asynchronous nature of the interface it is necessary for the controller to be informed that an instrument has accepted the listen address sequence and is ready to receive commands The controller will therefore wait for Acknowledge code 06H before sending any commands The addressed instrument will provide this Acknowledge The controller should time out and try again if no Acknowledge is received within 5
138. rrently selected Values are accepted in three formats integer 20 floating point 20 0 and exponential 2 EXP 1 For example to set a new frequency of 50kHz press FREQ followed by 50000 ENTER or 5 EXP 4 ENTER ENTER confirms the numeric entry and changes the generator setting to the new value CE Clear Entry undoes a numeric entry digit by digit ESCAPE returns a setting being edited to its last value 19 e MODULATION SUM TRIG IN and SYNC OUT call screens from which the parameters of those input outputs can be set including whether the port is on or off SWEEP similarly calls a screen from which all the sweep parameters an be set e Each channel has a key which directly switches the MAIN OUT of that channel on and off e MAN TRIG is used for manual triggering when TRIG IN is appropriately set and for synchronising two or more generators when suitably connected together MAN HOLD is used to manually pause arbitrary waveform output and sweep the output is held at the level it was at when MAN HOLD was pressed e UTILITY gives access to menus for a variety of functions such as remote control interface set up power up parameters error message settings and store recall waveforms to from non volatile memory the STORE and RECALL keys can also be used to directly access the non volatile stores e The INTER CHannel and COPY CHannel keys multi channel instruments only directly call screens from which channel to channel phase locki
139. rs show immediately they are changed Alternatively markers can be input as patterns by using the patterns sub menu PATTERN 00000000 start 00000 stop 01023 exit do pattern 0 The start and stop addresses of the markers within the waveform are set using the start and stop soft keys respectively followed by a direct keyboard entry or by rotary control The pattern itself is set in the top line of the display press the soft key to the right of PATTERN and enter the sequence of 1s and Os using 1 and 0 from the keyboard which auto increments to the next character or with the rotary control using the cursor keys to move the edit cursor along the pattern The pattern consists of 16 values if the cursor keys are used to skip over some character positions these will automatically be filled with the value of the last one specified to the left The pattern is entered repeatedly across the whole range defined by the start and stop addresses when the do pattern soft key is pressed pressing exit returns to POSITION MARKER EDIT screen without implementing the pattern Pressing the clear all soft key displays a request for confirmation that all markers should be cleared from the waveform Pressing clear cancels all the markers and returns the display to POSITION MARKER EDIT pressing cancel aborts the clear Arbitrary Waveform Sequence 48 Up to 16 arbitrary waveforms may be linked in a sequence Each waveform can have a loop
140. s no output queue which means that the response formatter will wait indefinitely if necessary until the instrument is addressed to talk and the complete response message has been sent before the parser is allowed to start the next command in the input queue Commands are sent as lt PROGRAM MESSAGES gt by the controller each message consisting of zero or more lt PROGRAM MESSAGE UNIT gt elements separated by lt PROGRAM MESSAGE UNIT SEPARATOR gt elements A lt PROGRAM MESSAGE UNIT gt is any of the commands in the remote commands list A lt PROGRAM MESSAGE UNIT SEPARATOR gt is the semi colon character 3BH lt PROGRAM MESSAGES gt are separated by lt PROGRAM MESSAGE TERMINATOR gt elements which may be any of the following NL The new line character OAH NL END The new line character with the END message SEND The END message with the last character of the message Responses from the instrument to the controller are sent as lt RESPONSE MESSAGES gt A lt RESPONSE MESSAGE gt consists of one lt RESPONSE MESSAGE UNIT gt followed by a lt RESPONSE MESSAGE TERMINATOR gt A lt RESPONSE MESSAGE TERMINATOR is the new line character with the END message NL END 83 Each query produces a specific lt RESPONSE MESSAGE gt which is listed along with the command in the remote commands list lt WHITE SPACE gt is ignored except in command identifiers e g C LS is not equivalent to CLS lt WHITE SPACE gt is def
141. s specified by the ARBEDLMTS command Due to the binary data block this command cannot be used over the RS232 interface Change the size of arbitrary waveform lt cpd gt to lt nrf gt Change the name of arbitrary waveform lt cpd1 gt to lt cpd2 gt Set the waveform point at address lt nfr1 gt in arbitrary waveform lt cpd gt to lt nrf2 gt Draw a line in arbitrary waveform lt cpd gt from start address data lt nrf1 gt lt nrf2 gt to stop address data lt nrf3 gt lt nrf4 gt Insert the standard waveform lt cpd2 gt into the arbitrary waveform lt cpd1 gt from start address lt nrf1 gt to stop address lt nrf2 gt lt cpd2 gt must be one of lt SINE gt lt SQUARE gt lt TRIANG gt lt DC gt lt POSRMP gt lt NEGRMP gt lt COSINE gt lt HAVSIN gt lt HAVCOS gt or lt SINC gt and lt cpd1 gt must be an existing arbitrary waveform Insert the arbitrary waveform lt cpd2 gt into arbitrary waveform lt cpd1 gt Use that part of lt cpd2 gt specified by the ARBEDLMTS command and insert from start address lt nrf1 gt to stop address lt nrf2 gt lt cpd1 gt and lt cpd2 gt must both be existing arbitrary waveforms but they cannot be the same waveform Block copy in arbitrary waveform lt cpd gt the data from start address lt nrf1 gt to stop address lt nrf2 gt to destination address lt nrf3 gt Adjust the amplitude of arbitrary waveform lt cpd gt from start address lt nrf1 gt to stop address
142. screens used for the setup depends on the number of pulses in the pulse train The first three screens define the parameters that apply to the whole pattern number of pulses overall pulse train period and baseline voltage subsequent screens define the pulse level width and delay for each pulse in turn 3 screens for pulse 1 then 3 screens for pulse 2 etc Pressing next on any screen calls the next setup screen finally returning the display to the STANDARD WAVEFORMS screen from which pulse train can be turned on and off pressing done returns the display directly to the STANDARD WAVEFORMS screen from any setup screen The pulse train is built only after next is pressed after the last parameter setup or whenever done is pressed assuming a change has been made The first screen shown above sets the number of pulses 1 10 in the pattern enter the number of pulses directly from the keyboard or by using the rotary control 53 54 Pressing next calls the pulse train period screen Enter pulse train period 100 0Ous done next The period can be set with 4 digit resolution from 100 00ns to 100s by direct keyboard entries or by using the rotary control Pressing next calls the baseline voltage screen the last of the general setup screens Enter the baseline voltage 0 000 V done next The baseline is the signal level between the end of one pulse and the start of the next i e it is the level all pulses st
143. signal at TRIG IN until the same level on the opposite edge With chan x selected the Trigger Out signal from the adjacent channel x is used to gate the waveform the source of the Trigger Out signal on that channel x is set up as described in the previous section Gate Polarity If slope onthe TRIGGER IN setup screen is setto positive the gate will open at the threshold on the rising edge and close on the threshold of the falling edge of an external gating signal i e the gate signal is true when the TRIG IN signal is high If the slope is set negative the gate signal is true when the TRIG IN signal is low The default setting of positive should be used for gating with the Internal Trigger Generator or an adjacent channel s Trigger Out Start Phase 36 Press setup onthe MODE screen to access the TRIGGER GATE SETUP screen on which the start phase can be set TRIGGER GATE SETUP BURST CNT 0000001 PHASE 000 0 actual 000 0 The start phase i e the point on the waveform cycle at which the gated waveform starts can be selected by pressing the phase soft key followed by direct entries from the keyboard or by using the rotary control Since the waveform cycle is always completed at the end of the gated period the start phase is also the stop phase The phase can be set with a precision of 0 1 but the actual resolution is limited with some waveforms and at certain waveform frequencies as detailed below To indic
144. sing ARB and SEQUENCE respectively and are described in detail in their appropriate sections Pulse and pulse train are also accessed from the standard waveforms screen but are sufficiently different to justify their own section in the manual Much of the following descriptions of amplitude and offset control as well as of Mode Sweep etc in following sections apply to arbitrary and sequence as well as standard waveforms for clarity any differences of operation with arbitrary sequence pulse and pulse train are described only in those sections Setting Generator Parameters Waveform Selection STANDARD WAVEFORMS sine square triangle Pressing the STD key gives the STANDARD WAVEFORMS screen which lists all the waveforms available the rotary control or cursor keys can be used to scroll the full list back and forward through the display The currently selected waveform sine with the factory defaults setting is indicated by the filled diamond the selection is changed by pressing the soft key beside the required waveform Frequency STANDARD FREQUENCY 10 00000 kHz freq period Pressing the FREQ key gives the STANDARD FREQUENCY screen With freq selected as shown above the frequency can be entered directly from the keyboard in integer floating point or exponential format e g 12 34 kHz can be entered as 12340 12340 00 or 1 234 exp 4 etc However the display will always show the entry in the most appropriate en
145. soft key calls the WAVE OFFSET screen WAVE OFFSET 0000 start 00400 stop 01000 undo exit save 0 The waveform offset can be changed on a section of the waveform defined by the start and stop addresses Set the addresses by pressing the appropriate soft key and making entries directly from the keyboard or by rotary control The data values over the specified section of the waveform are offset by the value entered in the WAVE OFFSET field Press the appropriate soft key and make entries direct from the keyboard or by using rotary control Entries in the range 4096 to 4095 will be accepted this permits in the extreme waveform sections with values at the 2048 limit to be offset to the opposite limit of 2047 Warnings are given when the offset causes clipping but the entry is still accepted The original waveform can be restored by pressing the undo _ soft key Offset edit operates on the version of the waveform in the channel currently selected by the channel SETUP keys the effect of the edit can be seen by selecting the waveform to run on that channel When the offset has been modified as required the new waveform can be saved by pressing the save key the action of saving modifies the waveform in the backup memory and then any other copies of the waveform in other channel memories Once saved the original waveform cannot be recovered Pressing exit returns tothe EDIT FUNCTIONS screen without change Wave Invert Pressing the
146. specific to the intended remote control mode Remote command format and the remote commands themselves are detailed in the Remote Commands chapter Address and Baud Rate Selection For successful operation each instrument connected to the GPIB or addressable RS232 system must be assigned a unique address and in the case of addressable RS232 all must be set to the same Baud rate The instrument s remote address for operation on both the RS232 and GPIB interfaces is set via the remote menu on the UTILITY screen see System Operations section REMOTE interface RS232 Oaddress 05 baud rate 9600 With interface selected withthe interface softkey the selection can be toggled between RS232 and GPIB with alternate presses of the soft key the cursor keys or by using the rotary control With address selected the soft key cursor keys or rotary control can be used to set the address With baud rate selected the soft key cursor keys or rotary control can be used to set the baud rate for the RS232 interface When operating on the GPIB all device operations are performed through a single primary address no secondary addressing is used NOTE GPIB address 31 is not allowed by the IEEE 488 standards but it is possible to select it as an RS232 address Remote Local Operation 74 At power on the instrument will be in the local state with the REMOTE lamp off In this state all keyboard operations are possible When the ins
147. sponse message and the input queue becomes full then the instrument enters the DEADLOCK state and an error is generated This will cause the Query Error bit to be set in the Standard Event Status Register a value of 2 to be placed in the Query Error Register and the response formatter to be reset thus clearing the output queue The parser will then start parsing the next lt PROGRAM MESSAGE UNIT gt from the input queue See the Status Reporting section for further information GPIB Parallel Poll 78 Complete parallel poll capabilities are offered on this generator The Parallel Poll Enable Register is set to specify which bits in the Status Byte Register are to be used to form the ist local message The Parallel Poll Enable Register is set by the PRE lt nrf gt command and read by the PRE command The value in the Parallel Poll Enable Register is ANDed with the Status Byte Register if the result is zero then the value of ist is O otherwise the value of ist is 1 The instrument must also be configured so that the value of ist can be returned to the controller during a parallel poll operation The instrument is configured by the controller sending a Parallel Poll Configure command PPC followed by a Parallel Poll Enable command PPE The bits in the PPE command are shown below f the response bit 0 low f the response Example To return the RQS bit bit 6 of the Status Byte Register as a 1 when true and a
148. sses of the appropriate soft key The last two error messages can be viewed by pressing the last error soft key Each message has a number and the full list appears in Appendix 1 See also Warnings and Error Messages in the Standard Waveform Operation section 67 Remote Interface Setup Pressing remote calls the REMOTE SETUP screen which permits RS232 GPIB choice and selection of address and Baud rate Full details are given in the Remote Operation section Reference Clock In Out Setting The function of the rear panel REF CLOCK IN OUT socket is set on the REF CLOCK I O screen called by pressing the ref clock i o soft key REF CLOCK I O input output phase lock The default setting is for the socket to be set to input i e an input for an external 10MHz reference clock When set to input the system is automatically switched over to the external reference when an adequate signal level TTL CMOS threshold is detected at REF CLOCK IN OUT but will continue to run from the internal clock in the absence of such a signal With the clock set to output a buffered version of the internal 10MHZz clock is made available at the socket With phase lock selected the socket can be setto bea master or slave when used for synchronising phase locking multiple generators See Synchronising Generators section for full details Cursor Marker Output 68 Pressing the cursor marker soft key calls the CURSOR MARKER OUTPUT screen
149. t lt nrf3 gt ARBPOINT lt cpd gt lt nrf1 gt lt nrf2 gt ARBRENAME lt cpd1 gt lt cpd2 gt ARBRESIZE lt cpd gt lt nrf gt BEEP BEEPMODE lt cpd gt BSTCNT lt nrf gt CLKFREQ lt nrf gt CLKPER lt nrf gt COPYCHAN lt nrf gt DCOFFS lt nrf gt EER FILTER lt cpd gt FORCETRG HOLD lt cpd gt LOCKMODE lt cpd gt LOCKSTAT lt cpd gt LOCAL Load data to an existing arbitrary waveform Returns the data from an existing arbitrary waveform Define a new or existing arbitrary waveform with name lt cpd gt and length lt nrf gt and load with the data in lt bin data block gt Define a new or existing arbitrary waveform with name lt cpd gt and length lt nrf gt and load with the data in lt csv ascii data gt Delete the arbitrary waveform lt cpd gt Set the limits for the arbitrary waveform editing functions to start at lt nrf1 gt and stop at lt nrf2 gt Insert the arbitrary waveform lt cpd2 gt into arbitrary waveform lt cpd1 gt Use that part of lt cpd2 gt specified by the ARBLIMITS command and insert from start address lt nrf1 gt to stop address lt nrf2 gt Insert the standard waveform lt cpd2 gt into the arbitrary waveform lt cpd1 gt from start address lt nrf1 gt to stop address lt nrf2 gt Invert arbitrary waveform lt cpd gt between start address lt nrf1 gt and stop address lt nrf2 gt Returns the length in points of the arbitrary waveform lt cpd gt Draw a l
150. t FTRACK gt or lt SLAVE gt Set the channel lock status to lt ON gt or lt OFF gt Returns the instrument to local operation and unlocks the keyboard Will not function if LLO is in force 93 LRN lt character data gt MOD lt cpd gt MODE lt cpd gt MODTYPE lt cpd gt OUTPUT lt cpd gt PHASE lt nrf gt POSNMKRCLR lt cpd gt POSNMKRPAT lt cpd1 gt lt nrf1 gt lt nrfi2 gt lt cpd2 gt POSNMKRRES lt cpd gt lt nrf gt POSNMKRSET lt cpd gt lt nrf gt PULSDLY lt nrf gt PULSPER lt nrf gt PULSWID lt nrf gt PULTRNBASE lt nrf gt PULTRNDLY lt nrf1 gt lt nrf2 gt PULTRNLEN lt nrf gt PULTRNLEV lt nrf1 gt lt nrf2 gt PULTRNMAKE PULTRNPER lt nrf gt PULTRNWID lt nrf1 gt lt nrf2 gt QER REFCLK lt cpd gt SCMLEVEL lt nrf gt SETUPCH lt nrf gt SEQCNT lt nrf1 gt lt nrf2 gt SEQSEG lt nrf gt lt cpd gt SEQSTEP lt nrf gt lt cpd gt SEQWFM lt nrf gt lt cpd gt SUM lt cpd gt SUMATN lt cpd gt SUMRATIO lt nrf gt SWPCENTFRQ lt nrf gt SWPDIRN lt cpd gt SWPMANUAL lt cpd gt SWPMKR lt nrf gt SWPSPACING lt cpd gt SWPSPAN lt nrf gt SWPSTARTERGQ lt nrf gt SWPSTOPERGQ lt nrf gt 94 Install data for a previous LRN command Set the modulation source to lt OFF gt lt EXT gt or lt PREV gt Set the mode to lt CONT gt lt GATE gt lt TRIG gt lt SWEEP gt or TONE Set the modulation type to lt AM gt or lt SCM gt Set the main outp
151. t key to select manual The four filter choices which are either automatically selected or set manually with the type soft key are as follows e 10MHz elliptic The automatic choice up to 10MHz for sine cosine haversine havercosine sinx x and triangle Would be the better choice for arb waveforms with an essentially sinusoidal content e 16MHz elliptic The automatic choice above 10MHz for sine cosine haversine and havercosine Not recommended for any other waveforms e 10MHz Bessel The automatic choice for positive and negative ramps arb and sequence e No filter The automatic choice for squareware pulse and pulse trains May be the better choice for arb waveforms with an essentially rectangular content 51 Pulse and Pulse trains Pulse and pulse trains are both selected and set up from independent menus on the STANDARD WAVEFORMS screen called by pressing the STD key Pulse and pulse trains have similar timing set ups and considerations but pulses are only unipolar with a maximum amplitude of 10Vpp whereas pulse trains can be bipolar with a maximum peak to peak of 20Vpp Pulse Set up 52 Pulse waveforms are turned on with the pulse soft key on the STANDARD WAVEFORMS screen pressing the setup soft key beside pulse calls the first of the pulse set up screens Enter pulse period 100 0 us exit next gt The pulse period can be set between 100 Ons and 100s with 4 digit resolution by direct entries
152. t trigger signal internal external adjacent channel or manual Useful for synchronising burst or gated signals e sweep sync Outputs the sweep trigger signal e phase lock Used to lock two or more generators Produces a positive edge at the 0 phase point The setting up of the signals themselves is discussed in the relevant sections later in this manual g trigger is described in the Triggered Burst Gate section and position marker under the Arbitrary Waveform Generation Pressing the SYNC OUT key calls the SYNC OUT setup screen SYNC OUT output on Omode auto a vysrc waveform sync SYNC OUT is turned on and off by alternate presses of the output soft key The selection of the signal to be output from the SYNC OUT socket is made using the sre source soft key repeated presses of sre cycle the selection through all the choices waveform sync position marker etc listed above Alternatively with the sre selected double headed arrow the rotary control or cursor keys can be used to step backwards and forwards through the choices The source selection of the SYNC OUT waveform can be made automatic auto or user defined manual with alternate presses of the mode soft key In automatic mode the SYNC OUT waveform most appropriate for the current main waveform is selected For example waveform sync is automatically selected for all continuous standard and arbitrary waveforms but trigger is selected in trigger o
153. tc but not with 2 001kHz for example For Clock Synthesised waveforms see Principles of Operation in the General chapter it is the PLL clock of the master which is distributed from master to slaves the clock frequency for master and slaves is therefore always the same The number of points comprising the waveforms should also be the same to ensure that the waveforms themselves appear locked From the foregoing it is clear that only DDS slaves can be locked to a DDS master and only Clock Synthesised slaves can be locked to a Clock Synthesised master In practice the constraints described are not severe as the most common use of synchronisation is to provide outputs of the same waveform at the same frequency or maybe a harmonic frequency but with phase differences Master Slave Allocation 62 Press the front panel INTERCHannel key to call up the inter channel set up screen mode indep Ophase 000 0 actual 000 0 status off view The mode soft key can be used to select between independent master master freqand slave the default mode is independent Only one master canbe set more than one master can be selected but when locking is turned on with the status soft key the set up will be rejected Master freq selects the master and sets frequency tracking for this to be operational the master and slave s must be set to the same frequency when locking is turned on In this mode when the fr
154. the Internal Trigger Generator or an adjacent channel or external of either polarity Alternatively SYNC OUT can be set to burst done onthe SYNC OUT setup screen sync out then provides a signal which is low while the waveform is running and high at all other times 37 Tone Mode General In Tone mode the output is stepped through a user defined list of up to 16 frequencies under the control of the signal set by the source soft key onthe TRIGGER IN setup screen This signal can be the Internal Trigger Generator an external trigger input the front panel MAN TRIG key or aremote command On multi channel instruments the control signal can also be the Trigger Out from an adjacent channel All standard and arbitrary waveforms can be used in Tone mode with the exception of pulse pulse train and sequence During Tone all waveforms are generated in DDS mode for fast phase continuous switching between frequencies For DDS operation all waveforms must be 4096 points in length this is the natural length for standard waveforms but all arbitrary waveforms are expanded or condensed in software to 4096 points when the Tone list is built This does not affect the original data Because DDS mode is used the frequency range for all waveforms is 1mHz to 10MHz in Tone mode including triangle ramp and squarewave which have different limits in continuous operation Tone Frequency Press the tone setup soft key onthe MODE screen called by pressing t
155. the range 0 to 255 Specified arb name does not exist Command illegal in sweep or tone mode Cannot set waveform frequency or period for a sequence Cannot set sample frequency or period for std waveforms dBm output units assume a 50 Ohm termination Specified units illegal for the selected waveform Command not available for RS232 Length value error in binary block Illegal value in arbitrary data Illegal tone number Illegal sequence segment number Cannot insert arb into itself Pattern value is illegal or pattern too long Illegal remote calibration command Command not available while sweeping 99 Appendix 2 SYNC OUT Automatic Settings The following automatic source src settings are made when auto mode is selected on the SYNC OUTPUT SETUP screen Waveform Position Burst Sequence Sweep Phase WAVEFORM B Sa BE TEE EE E a Standard Continuous Arbitrary Sequence GateTrig All Sweep aml O eT a TL Lock Master another it wv 100 Appendix 3 Factory System Defaults The factory system defaults are listed in full below They can be recalled by pressing RECALL followed by set defaults same setup All channels default to the same settings Main Parameters Std Wave Frequency Output DC Offset Zout Gate Trigger Parameters Source Period Slope Burst Count Phase Modulation Parameters Source Type Depth Sum Sweep Parameters Begin Frequency End Frequency Ma
156. tions described below one address cursor only for point edit The cursor signal can be displayed on a second channel of the scope or used to modulate the Z axis to bright up the stop and start addresses Note that the addresses are retained when moving between edit functions Thus if the stop and start addresses are set for waveform insert the same addresses appear as the defaults when wave amplitude edit is selected for example the addresses can of course subsequently be changed Resize Waveform Pressing the resize soft key on the MODIFY screen calls the Resize screen Resize wv01 old size 01024 new size 01024 cancel resize Resize changes the number of points in the waveform the new size can be larger or smaller than the old size When the new size is larger the software adds additional interpolated points When the size is smaller points are removed Reducing the waveform size may cause the waveform to lose significant data There is no undo for resize Resize is implemented by pressing the resize soft key or aborted by pressing the cancel soft key both return the display to the MODIFY screen Rename Waveform Pressing the rename soft key on the MODIFY screen calls the Rename screen Rename wv01 as y cancel rename 0 The new name can be entered below the original by selecting the appropriate character position with the cursor keys and then setting the character with the rotary control which scr
157. to 10MHz in phase locked mode The phase locking resolution of arbitrary waveforms will be less than 0 1 for waveforms of less than 3600 points The phase is fixed at 0 for pulses pulse trains and sequences 63 The table below summarises the phase control and frequency range for different waveforms Waveform Sine cosine haversine havercosine Square Triangle Ramp Sin x x Pulse amp Pulse Train Arbitrary Sequence Max Wfm Freq 10MHz 16MHz 100kHz 100kHz 100kHz 10MHz 40MS s clock 40MS s clock Phase Control Range amp Resolution 360 0 1 360 180 360 0 1 360 0 1 360 0 1 360 360 length or 0 1 360 360 length or 0 1 0 only When phase locking is turned on with the status soft key the slaves are re locked automatically after every phase or frequency setting change See also the Other Phase Locking considerations section Other Phase Locking Considerations The Master Slave Allocation and Phase Setting sections contain tables of specific limitations on the selection of frequency waveform type and phase setting range and resolution The following further points should also be considered 64 e The waveform filters introduce a frequency dependent delay above 1MHz this will affect the accuracy of the phase between locked waveforms at different frequencies e g 500KHz and 5MHz e Square waves which are 2 point Clock Sy
158. to a higher resolution if a step takes the value close to zero the increment size is maintained correctly as the offset is stepped negative For example if the display shows program 205 mVdc with the cursor in the most significant digit the rotary control will decrement the offset in 100mV steps as follows program 205 mVdc program 105 mVdc program 5 00 mVdc program 95 0 mVdc program 195 mVdc The actual DC offset at the MAIN OUT socket is attenuated by the fixed step output attenuator when this is in use Since it is not obvious when the signal is being attenuated the actual offset is shown in brackets as a non editable field below the programmed value For example if the amplitude is set to 2 5Vpp the output is not attenuated by the fixed attenuator and the actual DC offset in brackets is the same as that set The DC OFFSET display shows DC OFFSET program 1 50 Vdc actual 1 50 Vdc load hizo If the amplitude is now reduced to 250mVpp which introduces the attenuator the actual DC offset changes by the appropriate factor DC OFFSET program 1 50 Vdc actual 151 mVdc load hizo The above display shows that the set DC offset is 1 50V but the actual offset is 151mV Note that the actual offset value also takes into account the true attenuation provided by the fixed attenuator using the values determined during the calibration procedure In the example displayed the output signal
159. tor Handshake AH1 Talker T6 Listener L4 Service Request SR1 Remote Local RL1 Parallel Poll PPl Device Clear DC1 Device Trigger DT1 Controller CO Electrical Interface E2 GPIB IEEE Std 488 2 Error Handling The IEEE 488 2 UNTERMINATED error addressed to talk with nothing to say is handled as follows If the instrument is addressed to talk and the response formatter is inactive and the input queue is empty then the UNTERMINATED error is generated This will cause the Query Error bit to be set in the Standard Event Status Register a value of 3 to be placed in the Query Error Register and the parser to be reset See the Status Reporting section for further information The IEEE 488 2 INTERRUPTED error is handled as follows If the response formatter is waiting to send a response message and a lt PROGRAM MESSAGE TERMINATOR gt has been read by the parser or the input queue contains more than one END message then the instrument has been INTERRUPTED and an error is generated This will cause the Query Error bit to be set in the Standard Event Status Register a value of 1 to be placed in the Query Error Register and the response formatter to be reset thus clearing the output queue The parser will then start parsing the next lt PROGRAM MESSAGE UNIT gt from the input queue See the Status Reporting section for further information The IEEE 488 2 DEADLOCK error is handled as follows If the response formatter is waiting to send a re
160. trument is addressed to listen and a command is received the remote state will be entered and the REMOTE lamp will be turned on In this state the keyboard is locked out and remote commands only will be processed The instrument may be returned to the local state by pressing the LOCAL key however the effect of this action will remain only until the instrument is addressed again or receives another character from the interface when the remote state will once again be entered RS232 Interface RS232 Interface Connector The 9 way D type serial interface connector is located on the instrument rear panel The pin connections are as shown below Pin Name Description 1 No internal connection 2 TXD Transmitted data from instrument 3 RXD Received data to instrument 4 No internal connection 5 GND Signal ground 6 No internal connection 7 RXD2 Secondary received data addressable RS232 only 8 TXD2 Secondary transmitted data addressable RS232 only 9 GND Signal ground addressable RS232 only Single Instrument RS232 Connections For single instrument remote control only pins 2 3 and 5 are connected to the PC However for correct operation links must be made in the connector at the PC end between pins 1 4 and 6 and between pins 7 and 8 see diagram Pins 7 and 8 of the instrument must not be connected to the PC i e do not use a fully wired 9 way cable PC E INSTRUMENT AA D DCD i 1 O1 R
161. ts when the draw line soft key is pressed Wave Insert Pressing wave insert calls the wave insert screen wv01l gt wv02 00000 strt 00400 00512 stop 01000 exit insert Wave Insert places waveforms between programmable start and stop points Both standard and arbitrary waveforms can be inserted in the new waveform with the exception of pulse pulse train and sequence 45 A section of an arbitrary waveform can be inserted as defined by the left hand strt start and stop addresses e g 00000 and 00512 of wv01 onthe screen above these addresses default to the start and stop of the whole waveform but can be reset to define any section of the waveform Change the addresses by pressing the appropriate soft key and making entries from the keyboard or by rotary control The destination of the selected section of the source waveform in the new waveform is defined by the right hand strt start and stop addresses Change the addresses by pressing the appropriate soft key and making entries from the keyboard or by rotary control The insert is actioned by pressing the insert soft key If there is a size difference between the two sections of waveform then the software will expand or compress the source to fit the new waveform Compressing the waveform may lose some significant data To insert sections of the current waveform within itself see Block Copy Block Copy Pressing block copy calls the BLOCK COPY screen
162. ut lt ON gt lt OFF gt lt NORMAL gt or lt INVERT gt Set the slave generator phase to lt nrf gt degrees Clear all position markers from arbitrary waveform lt cpd gt Put the pattern lt cpd2 gt into the arbitrary waveform lt cpd1 gt from start address lt nrf1 gt to stop address lt nrf2 gt Clear the position marker at address lt nrf gt in arbitrary waveform lt cpd gt to 0 low Set the position marker at address lt nrf gt in arbitrary waveform lt cpd gt to 1 high Set the pulse delay to lt nrf gt sec Set the pulse period to lt nrf gt sec Set the pulse width to lt nrf gt sec Set the pulse train base line to lt nrf gt Volts Set the delay of pulse train pulse number lt nrf1 gt to lt nrf2 gt sec Set the number of pulses in the pulse train to lt nrf gt Set the level of pulse train pulse number lt nrf1 gt to lt nrf2 gt Volts Makes the pulse train and runs it similar to the WAVE PULSTRN command Set the pulse train period to lt nrf gt sec Set the width of pulse train pulse number lt nrf1 gt to lt nrf2 gt sec Query and clear query error number register Set the ref clock bnc to lt IN gt lt OUT gt lt MASTER gt or lt SLAVE gt Set the level for SCM to lt nrf gt Volts Select channel lt nrf gt Set count for sequence segment lt nrf1 gt to lt nrf2 gt Set the status of sequence segment lt nrf gt to lt ON gt or lt OFF gt Set the step on p
163. veform the old data is retained from the point where the new data ends If more data is sent the extra is discarded Define a new or existing arbitrary waveform with name lt cpd gt and length lt nrf gt and load with the data in lt bin data block gt If the arbitrary waveform does not exist it will be created If it does exist the length will be checked against that specified and a warning will be issued if they are different The edit limits will be set to the extremes of the waveform The data consists of two bytes per point with no characters between bytes or points The point data is sent high byte first The data block has a header which consists of the character followed by several ascii coded numeric characters The first if these defines the number of ascii characters to follow and these following characters define the length of the binary data in bytes If less data is sent than the number of points in the waveform the old data is retained from the point where the new data ends If more data is sent the extra is discarded Due to the binary data block this command cannot be used over the RS232 interface Arbitrary Waveform Editing NOTE Care should be take to ensure that all channels in the instrument are running in CONTINUOUS mode before using commands from this section Failure to observe this restriction 86 may give unexpected results ARBEDLMTS lt nrf1 gt lt nrf2 gt ARBDATACSV lt cpd gt lt csv ascii data gt S
164. vention adopted for the phase relationship between generators is the same as that used between channels i e a positive phase setting advances the slave generator with respect to the master and a negative setting delays the slave generator The status of the slave generator on the inter channel set up screen must be set to on automatic on a single channel generator Hardware delays become increasingly significant as frequency increases causing additional phase delay between the master and slaves However these delays can be largely nulled out by backing off the phase settings of the slaves Typically these hardware delays are as follows DDS waveforms lt 25ns lt 1 to 100kHz Clock Synthesised waveforms lt 300ns lt 1 to 10kKHz Clearly a multi channel generator gives much closer inter channel phase locking and is the recommended method for up to 4 channels Synchronising Having made the connections and set up the generators as described in the preceding paragraphs synchronisation is achieved by pressing the MAN TRIG key of the slave Once synchronised any change to the setup will require resynchronisation with the MAN TRIG key again 66 System Operations from the Utility Menu Pressing the UTILITY key calls a list of menus which give access to various system operations including storing recalling set ups from non volatile memory error messages power on settings and calibration Storing and Recalling Set ups
165. verse is true fora negative setting The signal that can be selected by the source soft key can be the Internal Trigger Generator an external trigger input the front panel MAN TRIG key a remote command and for mutli channel instruments Trigger Out of an adjacent channel a full explanation for each of these can be found in the Triggered Burst and Gate chapter DTMF Testing with a Multi Channel Generator An important use of Tone mode is DTMF Dual Tone Multiple Frequency testing in which 2 channels are set up with equal length lists of different frequencies and are triggered from a common signal The outputs are summed together using the internal sum facility see SUM chapter DTMF testing generally uses sinewaves in the frequency range 600HZz to 1 6kHz It is also possible to set up DTMF testing using two single channel instruments triggered by a common external signal and summed using the external SUM capability 39 Arbitrary Waveform Generation Introduction Arbitrary Arb waveforms are generated by sequentially addressing the RAM containing the waveform data with the arbitrary clock The frequency of the arb waveform is determined both by the arb clock and the total number of data points in the cycle In this instrument an arb waveform can have up to 65536 horizontal points The vertical range is 2048 to 2047 corresponding to a maximum peak peak output of 20 Volts Up to 100 waveforms can be stored in the 256k non volatile
166. voltages exceeding 10V CURSOR MARKER OUT Output pulse for use as a marker in sweep mode or as a cursor in arbitrary waveform editing mode Can be used to modulate the Z axis of an oscilloscope or be displayed on a second scope channel The output impedance is nominally 600Q and the signal level is adjustable from 2V 14V nominal from the cursor marker menu onthe UTILITY screen see System Operations section A Do not apply external voltages to this output 17 RS232 9 pin D connector compatible with addressable RS232 use The pin connections are shown below Pin Name Description 1 No internal Connection 2 TXD Transmitted data from instrument 3 RXD Received data to instrument 4 No internal connection 5 GND Signal ground 6 No internal connection 7 RXD2 Secondary received data 8 TXD2 Secondary transmitted data 9 GND Signal ground Pin 2 3 and 5 may be used as a conventional RS232 interface with XON XOFF handshaking Pins 7 8 and 9 are additionally used when the instrument is used in addressable RS232 mode Signal grounds are connected to instrument ground The RS232 address is set from the remote menu onthe UTILITY screen see System Operations section GPIB IEEE 488 The GPIB interface is not isolated the GPIB signal grounds are connected to the instrument ground The implemented subsets are SH1 AH1 T6 TEO L4 LEO SR1 RL1 PP1 DC1 DT1 CO E2 The GPIB address is set from the remote menuonthe UTILITY screen see S
167. waveform creation software supplied This is a powerful Windows based design tool that enables the user to create waveforms from mathematical expressions from combinations of other waveforms freehand or using a combination of all three techniques Waveforms created in this way are downloaded via the RS232 or GPIB interface Up to 100 waveforms may be stored with the length and name specified by the user Waveforms may be strung together to form a sequence of up to 16 steps Each waveform may have a user defined repeat count from 1 to 32768 All waveforms can be swept over their full frequency range at a rate variable between 30 milliseconds and 15 minutes Sweep can be linear or logarithmic single or continuous Single sweeps can be triggered from the front panel the trigger input or the digital interfaces A sweep marker is provided Amplitude Modulation is available for all waveforms and is controlled from the previous channel or from an external generator via the MODULATION input socket Signal Summing is available for all waveforms and is controlled from the previous channel or from an external generator via the SUM input socket All waveforms are available as a Triggered Burst whereby each active edge of the trigger signal will produce one burst of the carrier The number of cycles in the burst can be set between 1 and 1048575 The Gated mode turns the output signal On when the gating signal is true and Off when itis false Both Triggered
168. will invert the MAIN OUT output if DC OFFSET is non zero the signal is inverted about the same offset The exception to this is if the amplitude is specified in dBm since low level signals are specified in dBm OdBm 1mW into 509 224mVrms the sign is interpreted as part of a new amplitude entry and not as a command to invert the signal Note that for DC sinx x pulse train arbitrary and sequence amplitude can only be displayed and entered in the Vpp form further limitations on pulse train arbitrary and sequence amplitude are discussed in the appropriate sections DC Offset 24 DC OFFSET program 0 00 mVdc actual 0 00 mVdc load hiZ Pressing the OFFSET key gives the DC OFFSET screen The offset can be entered directly from the keyboard in integer floating point or exponential format e g 100mV can be entered as 1 or 100 exp 3 etc However the display will always show the entry in the most appropriate engineering units in this case 100mV During a new offset entry the key can be used at any time to set the offset negative alternate presses toggle the sign between and Turning the rotary control will increment or decrement the numeric value in steps determined by the position of the edit cursor flashing underline the cursor is moved by the left and right arrowed cursor keys Because DC offset can have negative values the rotary control can take the value below zero although the display may autorange
169. ximum frequency for phase locked DDS operation is 10MHz 7 An attempt is made to set the frequency too high during phase lock This error does not set phase lock to off the system simply inhibits the setting of the incorrect frequency In addition to the illegal setting combinations there are further considerations which affect the phase resolution and accuracy between channels see below a Phase setting between Channels The inter channel set up screen also has a field for setting up the phase of the slaves with respect to the master mode indep Ophase 000 0 actual 000 0 status off view Selecting the phase soft key allows the phase to be set by direct keyboard entry or by rotary control Setting the phase of a slave positive advances the waveform of the slave with respect to the master setting it negative delays the slave with respect to the master The phase of each slave channel can be set independently The phase of the master can also be set this is intended primarily for use in phase locking between two generators If both the master and the slaves are set to 90 say on the same generator then the waveforms will all be in phase again if the master is set to 90 and the slaves set to 90 the master and slave wavefoms will be 180 out of phase DDS generated waveforms can be phase locked with 0 1 resolution up to their maximum available frequency sine cosine haversine and havercosine are limited
170. yntax of the response is lt nr1 gt lt rmt gt Returns the value of the Status Byte Register in lt nr1 gt numeric format The syntax of the response is lt nr1 gt lt rmt gt Wait for operation complete true As all commands are completely executed before the next is started this command takes no additional action The generator has no self test capability and the response is always O lt rmt gt Query and clear execution error number register The response format is nr1 lt rmt gt Query and clear query error number register The response format is nr1 lt rmt gt Miscellaneous Commands LRN LRN lt character data gt RST RCL lt nrf gt SAV lt nrf gt TRG COPYCHAN lt nrf gt HOLD lt cpd gt FILTER lt cpd gt BEEPMODE lt cpd gt BEEP LOCAL Returns the complete set up of the instrument as a hexadecimal character data block To re install the set up the block should be returned to the instrument exactly as it is received The syntax of the response is LRN lt Character data gt lt rmt gt The settings in the instrument are not affected by execution of the LRN command Install data for a previous LRN command Resets the instrument parameters to their default values see DEFAULT INSTRUMENT SETTINGS Recalls the instrument set up contained in store number lt nrf gt Valid store numbers are 0 9 Recalling store 0 sets all parameters to the default settings see DEFAULT INSTRUMENT SETTIN
171. ystem Operations section 18 General Initial Operation This section is a general introduction to the organisation of the instrument and is intended to be read before using the generator for the first time Detailed operation is covered in later sections starting with Standard Waveform Operation In this manual front panel keys and sockets are shown in capitals e g CREATE SYNC OUT all soft key labels entry fields and messages displayed on the LCD are shown in a different type font e g STANDARD WAVEFORMS sine Switching On The power switch is located at the bottom left of the front panel At power up the generator displays the installed software revision whilst loading its waveform RAM if an error is encountered the message SYSTEM RAM ERROR CHECK BATTERY will be displayed see the Warnings and Error Messages section Loading takes a few seconds after which the status screen is displayed showing the generator parameters set to their default values with the MAIN OUT outputs set off Refer to the System Operations section for how to change the power up settings to either those at power down or to any one of the stored settings Recall the status screen at any time with the STATUS key a second press returns the display to the previous screen On multi channel instruments the status shown is that of the channel selected by the SETUP keys this is the channel currently enabled for editing and is always the last channel selected
172. z to 40MHz Arbitrary waveforms have a user defined length of 4 to 65536 points Squarewaves use a fixed length of 2 points and pulse and pulse train have their length defined by the user selected period value DDS Mode 22 In DDS mode Direct Digital Synthesis all waveforms are stored in RAM as 4096 points The frequency of the output waveform is determined by the rate at which the RAM addresses are changed The address changes are generated as follows The RAM contains the amplitude values of all the individual points of one cycle 360 of the waveform each sequential address change corresponds to a phase increment of the waveform of 360 4096 Instead of using a counter to generate sequential RAM addresses a phase accumulator is used to increment the phase 38 Bit 12 Bit 16 Bit RAM ADDRESS 4 Top Bits PHASE 38 Bit CLOCK sets to 0000 INCREMENT REGISTER PHASE ACCUMULATOR On each clock cycle the phase increment which has been loaded into the phase increment register by the CPU is added to the current result in the phase accumulator the 12 most significant bits of the phase accumulator drive the lower 12 RAM address lines the upper 4 RAM address lines are held low The output waveform frequency is now determined by the size of the phase increment at each clock If each increment is the same size then the output frequency is constant if it changes the output frequency changes as in sweep mode The generator uses a

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