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

Magnus Danielson cfmd at bredband.net
Tue Aug 23 14:57:57 EDT 2005


From: Alberto di Bene <dibene at usa.net>
Subject: [time-nuts] Re: Accuracy of a sound card
Date: Tue, 23 Aug 2005 19:35:58 +0200
Message-ID: <430B5E7E.2000700 at usa.net>

Alberto,

> Just for the sake of curiosity and to end this topic, I measured the
> accuracy of another sound card I have in my PC, a Terratec Aureon Sky. A
> good card, but not of the same class of the Delta 44. But it was more
> accurate... 40001.5 Hz which translates into an error of 37.5 +- 2.5 ppm

Which sounds about right. I would not assume that those are much better than
50 ppm crystals normally. Expect those frequencies to be different at a later
date since they probably vary with temperature, voltage rails and add
oscillator aging to the mix. Personally I care more about the high frequency
jitter than the exact sampling frequency and its slow drifting around in the
neighborhood of correct sampling-rate. The time-nut in me would try to figure
out a way to lock it, just because I can lock it one way or another. I am not
sure that such an exercise would greatly improve the state of things thought.

Cheers,
Magnus




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