Before we leave the case of amplitude-complementary, two-channel, critically sampled, perfect reconstruction filter banks, let's see what happens when is the simplest possible lowpass filter having unity dc gain, i.e.,
(12.29) |
(12.30) |
Thus, both the analysis and reconstruction filter banks are scalings of the familiar Haar filters (``sum and difference'' filters ). The frequency responses are
which are plotted in Fig.11.16.