Hi
> On Jun 1, 2017, at 10:04 PM, Donald E. Pauly <[email protected]> wrote: > > https://www.febo.com/pipermail/time-nuts/2017-May/105566.html > > The lock system on the HP5071 is complex and expensive. My plan to > improve the HP5061B is to to use a pair of third overtone crystals > running at 91.9 mc and 100 mc. I have come up with the magic numbers > to lock them together. This eliminates all multipliers with the > exception of the A4 board. The 12.61 mc synthesizer input presently > wastes half the microwave power produced by the 90 mc input in the > unused lower sideband. Therefore only half the 91.9 mc drive is > required. > > Eight bit ECL dividers in one package are available to perform the > necessary lock. When multiplied by 100 to the cesium resonance line, > the 91.9 mc frequency is a few cycles high so that C field currents > are reasonable. With crystal cuts for zero temperature coefficient at > 25°C, it is possible to get along without an oven. Room temperature > performance at 25°C±5°C is ±15·10^-9. I would suggest you check a few real crystals over the 20 to 40C range …. With all the “stuff” in a 5061, it will change (rise) at least 10C after turn on. Bob > Oscillator warm up time would > be measured in seconds. > > Square wave modulation of variable frequency and amplitude shows > promise for reducing the noise effects of the beam tube. You can > smoothly change the lock time constant, deviation and frequency. This > would avoid the big disturbance of the HP5061B when you switch from > OPR to LTC. (OPR=operate with 1 second time constant, LTC=operate with > 100 second time constant) > > πθ°μΩω±√·Γλ > WB0KV > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
