Subject: Re: [linux-audio-dev] JAAA Bandw parameter
From: Fons Adriaensen (fons.adriaensen_AT_skynet.be)
Date: Sun Dec 12 2004 - 23:18:33 EET
On Sun, Dec 12, 2004 at 09:03:32PM +0300, Andrew Gaydenko wrote:
> Probably, the last questions today :-)
>
> 1. What is the meaning of the "10 * log10 (Fsample / 2)" part?
It's just the frequency range expressed in dB.
No = noise density = power per Hertz.
No * frequency_range = noise_power.
In dB, the multiply becomes an addition.
And since the maximum signal level is O dB, SNR = -noise_power.
> 2. When noise spectrum is approximately flat - is there
> a common correlation with A-weighted value (say, "about 10db")?
I have no exact value at hand, but yes, it will be something like
10 dB. Most manufacturers of sound cards give the A-weighted figure
(if anything at all) -- it looks better :-)
-- FA
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