MODEL DG535 Digital Delay / Pulse Generator - SLAC

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TIMEBASE DRIFTThe drift of the timebase over several hours issubstantially less (x10 to x100 less) than theabsolute timebase error. The major factor in thetimebase drift is the instrument's temperature:after the instrument has warmed up, thetimebase drift is about 0.5 ppm/°C for thestandard timebase, and about 0.05 ppm/°C forthe optional timebase. The drift between severalDG535's which are used in the same experimentmay be eliminated by daisychaining thereference output from one DG535 to thereference input on the other DG535's.JITTERVarious noise sources in the DG535 modulatethe time delay for the outputs causing "jitter".Some of these noise sources are common to allof the channels, others are independent. Thedistribution of the pulses around the desiredtime can be approximated by a Gaussian (or"normal") distribution:where,p(t)= probability of pulse occurring at time tT = set time for the output (mean value)σ = standard deviation of the distributionFigure 4 shows the shape of the Gaussiandistribution and the relations between the rms jitterand the peak-to-peak jitter.The rms jitter, σ, is a function of the delay setting.The jitter is about 50 ps rms for delays less than100µs. For short delays, the peak-to-peak jittermeasured on an oscilloscope is about four times therms jitter. For long delays, the observed jittermeasured on an oscilloscope isprimarily due to the jitter of the oscilloscope'shorizontal (timebase) deflection circuits. For a good300 MHz oscilloscope, the rms jitter is typically (25ps + 10 ppm of the time base).The rms jitterm, as a function of time delay, isshown in Figure 5 for a Tektronix 2465oscilloscope, the DG535 using an internal timebase,and for a DG535 with an ideal external source. Thejitter for time delays longer than 10 seconds, usingthe ideal external source, is due to the drift of theanalog jitter compensation circuits in the DG535. Itcan be seen from this figure that the Tek 2465 scopewould show an apparent jitter of 1 ns rms at 100 µseven though the DG535's jitter is only 50 ps rms.CHANNEL to CHANNEL INTERACTIONThere is a small interaction (pulling) betweenchannels A and B and between channels C and Dwhen these channels are set within 10 ns of each8
other. The pulling of one channel by the other istypically less than 100 ps.TIME DELAY vs REPETITION RATEThe time delay for any channel may change by200 ps as the pulse repetition rate is changedfrom single shot to the maximum rate of 1/(1 µs+ longest delay). The burst mode of triggeringis, effectively, a rapid change of the pulserepetition rate.9
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: STORE and RECALL MENUSThere are ten
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 28 and 29: GPIB PROBLEMSThe first requirement
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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