Hi Single mixer into a computing counter was the way this stuff was done for a *lot* of years. The sort of resolution you needed a fancy counter for back in 1969 is well within the F7 board’s capabilities. What you get for resolution is often less of an issue than the accuracy of the readings. (= you can get a lot of digits ). We certainly did ADEV work into the parts in 10^-13 range (one second tau) with single mixer systems for a lot of years. No fancy (today) state of the art limiters involved …Cheap setups to run thousands of oscillators through.
Bob > On Apr 26, 2017, at 7:10 PM, Bert Kehren via time-nuts <time-nuts@febo.com> > wrote: > > We do it and get at 1 sec 1 E-13 resolution and 1 E-12 accuracy for the > work we do. > Bert Kehren > > > In a message dated 4/26/2017 3:00:54 P.M. Eastern Daylight Time, > alw.k...@gmail.com writes: > > I am surprised that no one has mentioned the idea of heterodyning a > known frequency with the unknown to measure the unknown. I use a > Minicircuits doubly balanced mixer fed on one port from a PTS160 > synthesizer that is locked to 10 mhz. from a TrueTime xl-ak GPS locked > receiver. The second port is fed by the unknown though an attenuator. > The third port of the mixer gives me the sum and difference. If the > difference is an audio note then a cheep but frequency locked counter > will read out the difference or measure the period of the beat note > which can be added to the frequency of the synthesizer. A program such > as Lady Heather can also be used to determine the audio frequency to > much less then sub-cycle accuracy. The only fly in the ointment is > figuring out which side of the unknown the synthesizer is set to. > > Alternatively, the PTS160 with 0.1 cycle control can be set to nearly > zero beat with the unknown. Then watching either lissajous or dual > trace scope patterns and timing the beat notes one can get the unknown > frequency very close. > > Al, retired, mostly > AKA k9si > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.