[time-nuts] Re: Accuracy of a sound card

Poul-Henning Kamp phk at phk.freebsd.dk
Tue Aug 23 14:55:34 EDT 2005


In message <430B6A33.1090004 at erols.com>, Chuck Harris writes:

>No one has yet addressed the actual oscillator that is on board the sound card.
>What are they using on the Delta 44?  ... the Aureon Sky?  I would have much
>more confidence if they would at least use a cheap TCXO module.

Using a tcxo for a soundcard is the technical equivalent of using
twelve handpolished and individually goldplated railroad tracks for
loudspeaker cable:  It would look impressive but be pointless.

The A/D converters used and the heavyhanded analog anti-alias
filtering means, that any sort term frequency change in the order
of 1PMM/minute is not measurable or hearable by any current means:
the phase difference only shows up as one nanosecond after 44 seconds
of audio.

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk at FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.




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