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.