Review of STFT Filterbanks

Let's take a look at some of the STFT processors we've seen before, now viewed as polyphase filter banks. Since they all use FFTs to perform overlap-add decompositions of spectra, they are all efficient, but most are oversampled in time and/or frequency as ``filter banks'' go. Oversampling is usually preferred outside of a compression context, and normally required when spectral modifications are to be performed. The STFT also computes a uniform filter bank, but it can be used as the basis for a variety of non-uniform filter banks, as discussed in §10.7, to give frequency resolution more like that of hearing (§7.3).

For each selected STFT example below, a list of filter-bank properties is listed, followed by some discussion. Most of the properties are determined by the choice of FFT window $w$ and FFT hop size $R$ .