In a message dated 4/29/2007 04:13:30 Pacific Daylight Time, [EMAIL PROTECTED] writes:
>Indeed. Three-four transistors and a handfull of caps and resistors. The >Z3801A uses the 10 MHz clock and thus require a x1000 interpolation, which is >easy enought to acheive. Look at the HP5335A service manual for further >details. What you do is that you stretch the error-pulse (1-2 cycles) by >charging a cap with one current and discharging it with another, the output is >then run into a comparator for the sake of gain. This stretched pulse is then >measured with the coarse clock and voila! Hi Magnus, I respectfully disagree, if it was that easy to get 100ps accuracy and resolution, then the 53132A would have it and not 150ps I would think. Also, the PRS10 Stanford Rubiudium would have better than 1ns resolution for time-tagging. I think they actually do resolve better than 1ns, but don't use it. On the Z3801A I am still seeing folks speculate that it has 100ps resolution just because that's what they print out as the averaged value. Does anyone have schematics to confirm this? The user manual even states that the number is an averaged version of the true Time Interval. Same for the 58503B. There is an easy way to verify this for anyone with access to a Z3801A or 58503B: Both units use the VP Oncore, speced at 31ns RMS sawtooth 1PPS jitter and at around 100ns peak to peak jitter. So if the Time Intervall circuit was not doing any filtering (which we know it does, since the HP manuals state that it does), then the Standard Deviation of the PTIM:SYNC:TINT? query results should have a peak to peak result slightly worse than 100ns, and a standard deviation of around 30ns. Of course we would have to add the OCXO noise and the quantization error on top of these values. Has anyone done any analysis on the TI values that the Z3801A gives (besides GPSCon, which gives about 50ns pk to pk and 10+ns Standard Deviation for most Z3801A'a)? bye, Said ************************************** See what's free at http://www.aol.com. _______________________________________________ time-nuts mailing list [email protected] https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
