[time-nuts] Fast frequency counting question

Magnus Danielson magnus at rubidium.dyndns.org
Sun May 4 23:25:10 UTC 2008


From: Luis Cupido <cupido at mail.ua.pt>
Subject: Re: [time-nuts] Fast frequency counting question
Date: Mon, 05 May 2008 00:08:07 +0100
Message-ID: <481E41D7.1010203 at mail.ua.pt>

> Couldn't it be:
> digitizing, process the data with a sliding FFT
> (making a spectrogram) plus deconvolve
> with the system line broadening response,
> and if all chirps are equal then repeating
> the above N times for resolution increase.

Not quite so easy. First of all, this type of transient response signal is not
well suited for FFT. Then, I am not sure the repeatability of the signal is
valid to such a degree that an accurate curve is achieved. I think the basic
approach is fairly right, but that they are stretching the limits somewhat of
that particular counter for this specific measurement.

Cheers,
Magnus




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