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multi sampling frequency filtering

Started by Fred Nach October 11, 2005
Hi all !

I'm trying to design a digital graphical equalizer (8 bands), which can 
deal with many samlping frequency... so it should be able to equalize 
let say either in 48k, 44.1k, 22k, 32k... in the same way.
So my question is ... do I have to design an equalizer for each sampling 
frequency or is there a good (and memory coefficent table saving) trick ?

I'm think of maybe designing the filter for 48k and then place an 
upsampler filter before... but it's just a draft idea ...

Txxs in advance for your help !

Fred.
I have done this several times before. What you can do is to design a
table which keeps different filter coefficients. When sampling rate
changes you use different set of coefficients. The filters can simply
be IIR bandpass type.

There are some other tricks you may have to use. For example decimation
filter stage by stage will help you to deal with the low-frequency
filters.