MODEL DG535 Digital Delay / Pulse Generator - SLAC

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GPIB PROBLEMSThe first requirement for GPIB operation is toproperly attach GPIB cable and to specify thecorrect address for the instrument. The defaultGPIB address is 15, but any address between 1and 30 may be set from the front panel. Tocheck the GPIB address, press the GPIB menukey twice. A new GPIB address may be enteredby keying in the number and pressing the EXCkey.The DG535 will respond to commands only if itis addressed and the Remote Enable line (REN)is asserted. When this happens, the front panelgoes to the REMote state, which disables all of thekeys except the keyboard mode key, which allowsthe user to leave the REMote state.The program can prevent users from using thekeyboard by asserting the Local-Lockout state(LLO).Different GPIB controllers expect different "stringterminators" to finish each response from aninstrument. The default GPIB terminator for theDG535 is a carriage return and a linefeed with anEOI. The "GT" command may be used to changethe GPIB terminator if your controller requires adifferent one.18
CALIBRATIONThere are hundreds of bytes of calibration datain ROM which are determined when theinstrument is calibrated at the factory. Most ofthese calibration bytes will never need to beadjusted: they correct for unit-to-unit variations,which will not change with aging. Othercalibration bytes may need to be adjusted to recalibratethe instrument.All of the calibration bytes are stored in ROM,however, those which may need to be adjustedare also stored in nonvolatile RAM. The RAMbytes are the values that are used in theoperation of the instrument. These bytes aretransferred from ROM to RAM when (1) theunit is first calibrated, (2) if the RAM data isfound to be corrupted, or (3) by a request to"Recall Factory Cal" in the calibration menu.Only the bytes that are stored in RAM may bemodified by the end user in the calibrationprocedure.The procedure for the adjustment of thesecalibration bytes is detailed here. Thecalibration bytes are used to minimize jitter,adjust the full-scale analog delays to 12.50ns,adjust the offsets and amplitudes of the outputdrivers, adjust the trigger threshold offset, andto set the optional TCXO time base to exactly10MHz.Any part, or all, of the calibration proceduremay be done. If only an adjustment of thetimebase is desired there is no need to do theentire calibration procedure. If your calibrationattempt only makes things worse, you have theoption of recalling the factory calibrationconstants to restore the RAM values to theirfactory settings.REQUIRED EQUIPMENTA 300MHz scope with 500ps/div timescale suchas a Tektronix 2465. A frequency counter with atimebase better than 0.1ppm such as an HP5384A with option 004 (ovenize timebase) tocalibrate the optional 1ppm TCXO. A pulsegenerator to provide adjustable amplitude fastrisetime (less than 5ns) pulses such as an SRSDG535. You will also need several 50Ω coaxcables and about ten 50Ω terminators.CALIBRATION PROCEDUREStart by setting the instrument to the default settingswith a RECALL 0 EXC. This will set the triggermode to Single shot, the delays to zero, the outputlevels to TTL, normal polarity, and configure theoutput drivers for high impedance loads.You should recall the factory calibration values. Ifyou are going to do only a partial calibration youmay wish to write down calibration values that havebeen recently entered so that they may reenteredwithout redoing the calibration. To recall the factorycalibration values hold down the BSP key and pressthe RECALL key. The message "Rcl Fact Cal(EXC)" will appear. Now press the EXC button torecall the factory calibration parameters.Trigger Threshold CalibrationThe trigger threshold calibration is required only ifthe Ext Trigger input was damaged, and the inputJFET transistor, Q114, has been replaced. Thiscalibration adjusts the input offset for the triggerinput to cancel variations in the gate-to-sourcevoltage between JFETs.____________Recall default instrument settings byRECALL 0 EXC.Select Ext trigger and set the Trigger Inputto 50 Ω ( leave the Threshold = +1.00 VDC,Slope = + )Apply a 10 KHz 0 to +1.00 VDC pulse tothe Ext Trigger Input.Adjust the Trig Threshold value ( the lastitem in the BSP-GPIB Menu ) so that theTRIG LED blinks intermittently.Optional 1 ppm Internal Timebase CalibrationThis procedure should be done only if the /03optional 1ppm TCXO oscillator is installed (refer tothe rear panel serial number tag). There is noadjustment for the standard 25ppm time base._________Set the rear panel 10.000 MHz sourceswitch to the INT position.Attach a frequency counter to the 10.0 MHzreference output BNC. This output canprovide a 1V p-p output into a 50Ω load.Press the STORE Menu Key and adjust thevalue to set the reference frequency to10.000000 MHz ± 1Hz. This calibrates theinternal time base to 0.1ppm.19
Page 1 and 2: MODEL DG535Digital Delay / Pulse Ge
Page 3 and 4: Time Delay vs Repetition 9GPIB PROG
Page 5 and 6: Sheet #2 10 MHz Reference and 80 MH
Page 7 and 8: QUICK START INSTRUCTIONS(1) Make ce
Page 9 and 10: ABRIDGED COMMAND LISTINITIALIZATION
Page 11 and 12: GUIDE TO OPERATIONINTRODUCTIONThe D
Page 13 and 14: is remedied.To use the timebase in
Page 15 and 16: It is often desirable to trigger th
Page 17 and 18: STORE and RECALL MENUSThere are ten
Page 19: other. The pulling of one channel b
Page 22 and 23: 10.0MHz reference is too small or m
Page 24 and 25: incorrect cursor mode will have no
Page 26 and 27: and a trigger input impedance of 50
Page 30 and 31: CALIBRATION MENUSTo access the cali
Page 32 and 33: CIRCUIT DESCRIPTIONThe DG535 has th
Page 34 and 35: threshold, reference oscillator fre
Page 36 and 37: Each of the four delay channels beh
Page 38 and 39: portion of the delay is complete, A
Page 40: +10.000VDC reference is generated o
Page 43 and 44: C 301G 5-00056-512 .1U Cap, Stacked
Page 45 and 46: Q 302C 3-00177-321 2N2222 Transisto
Page 47 and 48: U 109 3-00201-340 MC10H105 Integrat
Page 52 and 53: FAST TRANSITION-TIMEMODULESOPTION 0
Page 54: SETUP FOR OUTPUT STEPS UP TO15 VOLT

MODEL DG535 Digital Delay / Pulse Generator - SLAC

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