Re: [Discuss-gnuradio] An interesting application for my new USRP... some input requested

[John Ackermann N8UR]

Larry Doolittle wrote:

> I think the FFT-based analysis is less than ideal.  You really want
> to track the phase, count cycles, and measure the phase difference
> over a defined time.  delta(phase)/delta(time) is the average frequency.
> Your phase error could be as small as a few milliradians, and you said
> the integration time is at least 10 minutes: your measurement error could
> approach a micro-Hertz, if your reference oscillator were perfect.

uHertz are nice. :-)

I guess the reason I've been fixated on an FFT is that the signal I'm 
looking for won't be the only one there -- there will be noise (natural 
and man0made), fading, and probably other signals within a few tens of 
Hz of the desired signal, so I've been visualizing an FFT with audio 
demod as the way to spot the signal I'm looking for in post-processing. 
 Once I have it spotted, of course, I could then apply other techniques.

John