[time-nuts] (no subject)

[cdelect at juno.com]

I am selling my NBS 106D DMTD unit. I have run a few thousand plots of various frequency standards using this unit over the years but  have replaced it with a different unit. Input an offset oscillator, a REF and A DUT to get started. Apply the start and stop signals to a counter (I have used the HP 53131A and the SR620 in the early days but they are severe overkill for a DMTD unit). I currently use a custom 8 digit counter. run the counters data into a laptop and use various software to do phase plots and Allan Deviation. These units were designed by the NBS and used to characterize oscillators for phase 1 of GPS, and I believe actually used by Dr Allan of Allan Variance fame. See https://nvlpubs.nist.gov/nistpubs/Legacy/IR/nbsir75-827.pdf for details of unit and schematics. This 106D version eliminated the 5Mhz resolver for phase adjustments and replaced it with switch selectable delays using selected lengths of coax. Also this unit is powered by internal supplies. I did replace the isolated BNC jacks with isolated SMA jacks. I also installed more modern op amps, a precision low TC resistor and low TC capacitor for the BW setting labeled 1000HZ. It is now actually 1HZ. any questions please ask! Asking $225.00 + shipping.
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