Re: Designing a first-order IIR filter

[Paul Kienzle]

On Nov 6, 2006, at 7:32 PM, Shaun Jackman wrote:

> I can use the `freqz' function to find the cutoff
> (-20 dB) frequency for a given filter, specified
> by its IIR coefficients and sampling period. However,
> if I have a desired cutoff frequency and given
> sampling period, how do I find the IIR coefficients
> that give the desired first-order filter?

octave-forge has butter, cheby1, cheby2 and ellip
for designing IIR filters.

- Paul