A032-ET - International Laser Ranging Service

Event Timer A032-ETFig.B-6.Fig.B-7.The upper fraction corresponds totime intervals between adjacentStop and Start pulses, the centralfraction – between adjacent Stoppulses and the bottom fraction -between adjacent Start and Stoppulses (they are coloured in blue).This indicates that each Start pulseis located between adjacent Stoppulses with some (about 1 ns)asymmetry. Note that there are notany unexpected time intervals thatcould indicate possible gaps in thecontinuous measurement.Using zoom for Y-axis one can seeeach fraction of time intervalsseparately and calculate its basicstatistics. For example, Fig.B-7shows the central fraction of “Stop-Stop” time intervals. Mean andRMS deviation of these timeintervals are 81,899.902 ns and 6.6ps respectively. This indicates thatthe own jitter of test signal isnegligible small as compared to thepredicted measurement resolution,and the actual timer resolutioneven better than the predicted one.As for “Start-Stop” time intervals(the bottom fraction in Fig.B-6), mean and RMS deviation of them are 81,898.778 ns and 7.1 psrespectively. In other words, the actual asymmetry of Start pulses location is 1.124 ns andabsolute instability of their periodicity is a little greater than that for the Stop pulses.Thus, as one can see, the A032.1 option used in the above measurement really supportsgapless event measurement at rate 12.210 KHz with RMS resolution better than 7 ps. Note thatthese characteristics are much better than that indicated in specifications as typical ones. Onthe other hand, the A032.1-C1 subsystem combined with this timer option results in completetiming system that can provide versatile analysis of pulse sequences with picosecondresolution.30