In a discrete wavelet filterbank, each basis signal is
interpreted as the impulse response of a bandpass filter in a
constant-Q filter bank:
Recall that in the STFT, channel filter is a shift of the zeroth channel-filter (which corresponds to ``cosine modulation'' in the time domain).
As the channel-number increases, the channel impulse response lengthens by the factor ., while the pass-band of its frequency-response narrows by the inverse factor .
Figure 11.32 shows a block diagram of the discrete wavelet filter bank for (the ``dyadic'' or ``octave filter-bank'' case), and Fig.11.33 shows its time-frequency tiling as compared to that of the STFT. The synthesis filters may be used to make a biorthogonal filter bank. If the are orthonormal, then .