Maybe for the records or for discussion also:

In case of a single pole filter I found out that one can fairly eas
compensate for a different frequency by re-calculating the b1 coefficient
in the recursion equation:
y[n] = a0*x[n] + a1*[n-1] + b1 * [n-1]

So if f1 is the 'old' sampling frequency and f2 is the frequency one like
to 'approximate' it should be possible to find a new b1 coefficient for th
new frequency via:
b1_new = 1-(1-b1)/(f1/f2)

I don't know if this is mathematically correct (maybe someone likes t
calculate this?), but as b1 defines the attenuation from one sample to th
next, changing b1 should be sufficient to compensate for a differen
sampling frequency in this simple case. (Probably this will have it'
limitations...)

What do you mean ?


Greetings,
Marcus