[time-nuts] HP-531xx calibrator nearing completion

Mark Sims holrum at hotmail.com
Wed Sep 13 20:50:05 EDT 2017

I used my prototype of a single channel of the calibrator's signal generator to generate and feed a 1.0V p-p 10 MHz square wave into a real HP-59992 J06 that a list member sent me from Australia for the cost of shipping... many thanks for that. (Does anybody know how to remove the button tops on the switches so I can replace a burned out bulb?)  

I used that to do a full "FINE" time interval calibration on my 53132A that I recently upgraded the firmware on (the firmware upgrade requires a full calibration... and my 53132A now shows commas between groups of three digits).   It passed with flying colors,  so it looks like the signals that my calibrator generates are  good to go.   

I'm going to order 50 PCBs tomorrow (along with boards for the X72 rubidium interface).  I'll probably be selling it as a kit of parts... unless I can con my friend into assembling them.   I'm shooting for something in the $25-$30 range.   It replaces the high dollar HP-8130A pulse generator,  unobtainium 5992A-J06 time interval calibrator, and a precision 5.000V reference.  

My calibrator requires a good 10 MHz input signal.  If your counter has the OCXO time base, you can probably use the counter's reference output.  I tried it when the OCXO timebase was off freq by 1.5 Hz (due to the firmware upgrade) and the time interval  would not calibrate.  It passed once the timebase was calibrated against a GPSDO.

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