28 May
2004
28 May
'04
6 p.m.
On Friday 28 May 2004 15:19, Ivica Ico Bukvic wrote:
Hmm, it would be a fun project then to come up with a
profiler of various
audio cards by recording and then capturing a specific buffer of audio
data. Then by comparing them (assuming that this drift is constant) see how
many empty samples there are (or if the playback is slower, how many
samples are missing), and then create a framework that allows real-time
resampling in order to compensate for that discrepancy whenever multiple
soundcards are being used :-D
I strongly suspect that you'd find your results to be non-repeatable. Many
factors can subtly influence the output frequency of even crystal-locked
SRGs: ambient temperature, power supply voltage variation, even component
aging.
This issue affects many more applications than just audio. *Any* system that
requires precise replication of clock (as, for example, most any digital
telecommunication scheme does) faces this dilemma. In the end, some form
*locking*, slave clock to master, is needed. A variety of methodologies,
such as PLL (phase lock loop) exist to do this, but the bottom line remains
that some sort of hardware support will be necessary.
Cheers!
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| Frederick F. Gleason, Jr. | Director of Broadcast Software Development |
| | Salem Radio Labs |
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| I know the answer! The answer lies within the heart of all mankind! |
| The answer is twelve? I think I'm in the wrong building. |
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