[time-nuts] Using cheap sound cards for measurements

Demian Martin demianm_1 at yahoo.com
Sun Aug 23 16:40:22 UTC 2009


Be careful of the Emu/Creative stuff. They have always has resampling in
their products in the past. This new generation doesn't but it still has an
inline DSP to muck around with the bits. Also the Windows (and MAC) sound
systems are notorious for resampling internally. This can be very hard to
get around. You can use ASIO drivers to go around the internal engine if you
write your app for that. The EMU 0202 isn't supported fully in Linux yet. 



Demian Martin
PDS


Ok, I have looked at a few USB cards and reviews. For SD radios, and as far 
as I can tell for time use, the Creative E-MU 0202 will do nicely, at a 
reasonable cost of $99.00.
According to the company info, the E-MU 0404 might be synchronizable; it 
costs about $150. The plug-in card (takes two slots) equivalent to the 0404 
is apparently the E-MU 1212.

It might be possible to modify the 0202 to provide an external clocking 
signal, at least to provide a more stable oscillator, I don't know. The 100 
ps jitter if true is satisfactory?

Oh, the 1212 input amplifiers are DC coupled (!).
I suggest, of course, that interested parties have a look at the website:
http://us.creative.com/products/welcome.asp?category=237

I'll probably be ordering an 0202 in the near future.

Don Latham 




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