[time-nuts] Low cost SDR suitable for phase noise measurement?

Bob Stewart bob at evoria.net
Thu Aug 11 18:25:44 EDT 2016

Thank Attila.  At this point I'm mostly just collecting ideas.  I hope to put something to copper in a month or two.


      From: Attila Kinali <attila at kinali.ch>
 To: Bob Stewart <bob at evoria.net>; Discussion of precise time and frequency measurement <time-nuts at febo.com> 
 Sent: Thursday, August 11, 2016 5:12 PM
 Subject: Re: [time-nuts] Low cost SDR suitable for phase noise measurement?
On Thu, 11 Aug 2016 19:29:08 +0000 (UTC)
Bob Stewart <bob at evoria.net> wrote:

> It looks like I've asked a question poorly, yet again.  So, let me try
> again.  I have this idea of combining a DMTD with an SDR.  So, said that
> way, it looks like what I really need is a 2-channel audio SDR.  And having
> said that, maybe what I'm looking for is an external USB sound card.  Those
> I can find.  I can probably even figure out how to convert them to DC and
> supply them with a disciplined oscillator, if needed.

If you are going the soundcard way, i would like to point you at
You can find there two pdfs how to build a phase noise measurement
system using USB soundcards (kindly translated by Azelio Borani).
Adapting this to a DMTD system using two low frequency inputs
shouldn't be too hard. But please be aware that you should not
go below 100Hz or so, if you want to prevent the ADC DC drift to
confund your measurement. Probably even stay around 1kHz.

            Attila Kinali

Malek's Law:
        Any simple idea will be worded in the most complicated way.


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