[time-nuts] HP-531xx calibrator nearing completion
holrum at hotmail.com
Mon Sep 11 11:47:11 EDT 2017
I connected a prototype of the HP-531xx calibrator signal circuits (input squarer, freq doubler, divider, output buffer, level shifter) to a TAPR TICC to see how stable the output was.
This prototype was built on perf board using DIP packaged 74AC logic so I was not expecting good results. Pleasant surprise... very good performance! There was no difference (within the limits of the TICC performance) in the calibrator xDEVs vs measuring the un-processed 5071A output.
The TICC was clocked by one 10 MHz output of a HP-5071A, calibrator by the other 10 MHz output. TICC input was the calibrator output divided to 1PPS by a TADD-2 Mini.
I also checked the output waveform with a 5 GS/s DSO. Rise time is less than a nanosecond. There is around 50 mV (10%) of ripple on the top/bottom of the square wave output (expected with DIP packaged parts and point to point wiring on perf board). Waveform symmetry is 50% (+/- the 200 ps DSO sampling rate).
The calibrator output is quite a bit better than what the HP-59992 J06 produces... The J06 180 degree phase shifter is off around 24 degrees (6 ns). It also degrades the rise time by around 1 ns.
Attached is a plot of the calibrator xDEVs
-------------- next part --------------
A non-text attachment was scrubbed...
Size: 59938 bytes
More information about the time-nuts