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Subject: Re: DSP: low pass filter

Re: DSP: low pass filter

From: [IDC]Dragon <idc-dragon_at_gmx.de>
Date: 2005-08-15

> Thanks, we got to the point that averaging is enough on IRC tonight
> too... but we had no way to calculate how many samples to average...

I suggest using an IIR filter instead of FIR. You need way less past samples
for each step. The most simple IIR filter is like a charge/discharge (first
order lowpass): e.g. take 90% of your "charge", 10% of the new value, to get
the new charge. Play with the parameters, generalized it's n and (1-n). If
you use less of the current, the thing becomes slower, lower corner
frequency.
Power of two gives the benefit of using shift instead of multiply. Use >16
bit for the charge.

Jörg

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Received on Mon Aug 15 21:25:28 2005

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