[LAU] Open Sound Interface project beginnings

Fons Adriaensen fons at linuxaudio.org
Wed Oct 26 16:01:13 UTC 2011


On Wed, Oct 26, 2011 at 08:52:14AM -0500, Charles Henry wrote:

> > http://sdr-widget.googlecode.com/files/Draft4_Sound_card_noise_floor_compare_2010_07_25_TF3LJ.pdf
> 
> This looks good to study--that analog board has great noise characteristics.

Yes. To get the full story you should also zoom in on the 0-500Hz range.
Noise density will rise in that range, and there will be mains frequency
harmonics leaking in.

Provided the noise density is flat in the audio range, the unweighted
S/N for 20 kHz bandwidth would be -(No + 43) dB, i.e. 114.8 dB for the
SDR Widget Lite Alpha2, which is quite good. For an A-weighted value
add 2.2 dB. 

The best way to measure the actual noise level would be jnoisemeter.

Ciao,

-- 
FA



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