slightly ot: DAT clock deviation

[Martin Czech]

:::Well, with the recording of the reference signal they are able to do the
:::crosscorrelation. Now, the most straigthforward way to get precission is just
:::to make a LONG recording. Yes, your pseudorandom noise will loop many times,
:::but you don't care. I have been sitting too many nigths listening to the
:::pulsating noise. Now, when you do such a recording, any drifts in clocks is
:::at least fairly limited.

Only problem: computer memory for FFT.
Or I have to look at programs for very long FFT length, like
these earthquake people have... Surely pretty slow.



:::You DO need a steep anti-aliasing filter. You should not settle with less 
than
:::8 poles. I would consider both Butterworth, Bessel and Gauss filters to do 
the
:::job.

I come to that in a follow up.



:::You could apply the filtering at the input, after the mic-amp and prior to 
the
:::S/H section.

I don't think so, because I need the reference signal also, and this is 
square pulses.

m.c.