[LAU] [alsa-devel] USB device gives wrong data?

[william estrada]

Now that is helpfull.  Thanks, I will try it when I get a chance.

Thanks Gordon.

William Estrada
MrUmunhum at popdial.com
Mt-Umunhum-Wireless.net ( http://Mt-Umunhum-Wireless.net )
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> Message: 1
> Date: Wed, 24 Oct 2007 11:05:35 +0100
> From: Gordon JC Pearce <gordonjcp at gjcp.net>
> Subject: Re: [LAU] [alsa-devel] USB device gives wrong data?
> To: linux-audio-user at lists.linuxaudio.org
> Message-ID: <200710241105.35908.gordonjcp at gjcp.net>
> Content-Type: text/plain;  charset="iso-8859-1"
> 
> On Tuesday 23 October 2007 00:05:13 James Cameron wrote:
> 
>>> How would you filter out noise?
>> You can filter out DC offset by measuring the offset you have, and
>> subtracting this measurement from your samples.
> 
> A better way would be to use a highpass filter.
> 
> Use something like:
> 
> 
> for (i=0; i<=NUM_SAMPLES; i++) {
>   hp_last = 0.9999f * hp_last + in[i] - hp_last_in;
>   hp_last_in = in[i];
>   out[i] = hp_last;
> }
> 
> You could optimise that a bit.
> 
> Gordon
> 
>