Now that is helpfull. Thanks, I will try it when I get a chance. Thanks Gordon. William Estrada MrUmunhum@xxxxxxxxxxx Mt-Umunhum-Wireless.net ( http://Mt-Umunhum-Wireless.net ) Ymessenger: MrUmunhum > Message: 1 > Date: Wed, 24 Oct 2007 11:05:35 +0100 > From: Gordon JC Pearce <gordonjcp@xxxxxxxx> > Subject: Re: [alsa-devel] USB device gives wrong data? > To: linux-audio-user@xxxxxxxxxxxxxxxxxxxx > Message-ID: <200710241105.35908.gordonjcp@xxxxxxxx> > 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 > > _______________________________________________ Linux-audio-user mailing list Linux-audio-user@xxxxxxxxxxxxxxxxxxxx http://lists.linuxaudio.org/mailman/listinfo/linux-audio-user
