[music-dsp] Newbie Q: how to implement a real-time high freq
lanceboyle at cwazy.co.uk
Tue Feb 1 05:27:37 EST 2005
Google digital filter design interactive
The top hit looks wonderful.
On Feb 1, 2005, at 12:25 AM, Qiangning Hong wrote:
> I am developing a real-time recording application. I am only
> interested in signal below 6KHz so I want to apply a low-pass filter
> on the input. As I know little about DSP, I copied the following
> filter from internet:
> y(n) = x(n) * a0 + x(n-1) * a1 + y(n-1) * b1
> w = 2 * framerate
> cutoff = 6000 * 2 * PI
> norm = 1 / (cutoff + w)
> b1 = (w - cutoff) * norm
> a0 = a1 = cutoff * norm
> It works but the output is not ideal. The signal above 6KHz is still
> too high and the output sounds a bit different with the original one.
> Can anyone point me to a correct way?
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