[time-nuts] disciplining sound card

[John Miles]

> -----Original Message-----
> From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
> Behalf Of Azelio Boriani
> Sent: Friday, July 06, 2012 2:36 PM
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] disciplining sound card
> 
> Exactly: this prevented me to buy the ESI Juli@ sound card. It was
> suggested by a fellow time-nut and this card is indeed very interesting
but
> in my opinion sound cards are not well defined about the sampling process.
> I need more details. The Juli@ has the greater than usual bandwidth, not
> limited to the audio spectrum but up to 90KHz, so it is perfect as a
> general digitizer for the VLF radio spectrum (DCF77, WWWB and others).

I may have missed some details about the intended use, but in any event, the
latency between the ADC and the software is influenced by a large number of
factors, some of which will introduce more uncertainty than the pipeline
characteristics of the ADC itself.  The best workaround might be to couple
some 1-pps energy into the signal being digitized.  This would effectively
'timestamp' the samples at the point where they are acquired, so the latency
would no longer be an issue.

-- john
www.miles.io