It is well known that it is a good idea to apply windowing to a signal, before obtaining its DFT and viewing its frequency response.
- But is it a good idea to apply windowing to the impulse response of a filter, before viewing its frequency response?
- Does the answer to this question depend on whether the filter is FIR or IIR?
I could perhaps see why windowing could be better than just truncating an IIR filter. But I can't decide whether the same applies to an FIR filter.
However, even in the case of an IIR filter, we usually don't do this. Instead we usually just plot the response as a function of the IIR filter's transfer function numerator & denominator coefficients (e.g. using
freqz in Python or Matlab).
So is it ever a good idea to window the impulse response of a filter?