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.k9si@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.

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.k9si@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.