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Discussion of precise time and frequency measurement

Re: [time-nuts] Frequency counter questions

jerry

Wed, Apr 26, 2017 11:17 PM

Sent via the Samsung Galaxy Note® Edge, an AT&T 4G LTE smartphone

-------- Original message --------
From: Bruce Griffiths bruce.griffiths@xtra.co.nz
Date: 4/26/2017 2:19 PM (GMT-08:00)
To: Discussion of precise time and frequency measurement time-nuts@febo.com, al wolfe alw.k9si@gmail.com
Subject: Re: [time-nuts] Frequency counter questions

Use a USB or LSB mixer, it only requires a few more parts and a little ingenuity.

Bruce

On 27 April 2017 at 06:52 al wolfe alw.k9si@gmail.com wrote:

     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

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I can measure to .001hz using my scope. I thought I mentioned that the other day? It depends on frequency and how much time you want to wait, I think the low frequencies take a lot longer to stabilize. Sent via the Samsung Galaxy Note® Edge, an AT&T 4G LTE smartphone -------- Original message -------- From: Bruce Griffiths <bruce.griffiths@xtra.co.nz> Date: 4/26/2017 2:19 PM (GMT-08:00) To: Discussion of precise time and frequency measurement <time-nuts@febo.com>, al wolfe <alw.k9si@gmail.com> Subject: Re: [time-nuts] Frequency counter questions Use a USB or LSB mixer, it only requires a few more parts and a little ingenuity. Bruce > > On 27 April 2017 at 06:52 al wolfe <alw.k9si@gmail.com> wrote: > > 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.