Re: Chebyshev IIR - cutoff frequency 0.5 leads to distortion?

Hi,

> you can also be having overflow problems internal to the filter
> calculations...
>
> does the distortion improve if you reduce the input signal amplitude?
>
> what type of distortion are you having?
>
> Mar
>

I have tested the Chebyshev with different amplitudes of the input signal. I
know that problem in connection with my FIR filters. There I got a strange
output by filtering a sinus wave, which showed a "huge"(?) amplitude.

All in all, it is the problem of coming closer to the Nyquist freq, e.g. I
have 44100Hz input, cutoff 0.5 or 0.495, and strange things happen:

type of distortion: Well, it is different to describe, so you can find my
output files here:
http://www-user.tu-chemnitz.de/~femi/cheb/

0.5c means cutoff value
4p stands for number of poles

Ciao, Michael


.

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