[time-nuts] EFC tracking

[jimlux]

Didier Juges wrote:
> Steve,
> 
> You may want to check the "Analog Devices MiniKit for ADuC702x-series".
> 
> http://www.google.com/search?q=Analog+Devices+MiniKit+for+ADuC702x-series
> 
> This kit includes a 24 bit ADC and integrated ARM processor in a small PWB with all the tools and sample code to do what you want with very little code to write (you can probably use the sample code as-is).
> 
> The kit is $30 (or $35, depending on where you look...) and you will easily spend that much building something that will not work as well using your sound card.
> 
> Sound card ADCs are intended for audio, and I'll bet their linearity does not come close to that of the ADuC702x series, if you can even get the spec for it.
> 


sound card ADCs, the high end 24 bit ones, are pretty darn linear, and 
have pretty good SNR as well.  120-130dB S/(N+Distortion+etc) wouldn't 
be unusual.

The surrounding circuitry is likely to be a bigger problem.  1 LSB on a 
1V p-p 24bit converter is about 60nV.