User`s guide

Dyadic Synthesis Filter Bank
5-160
highpass and lowpass direct-form II transpose filter in the filter bank. The
values of these coefficients are typically computed together with the dyadic
analysis coefficients using the wavelet family functions in the Wavelet Toolbox
(see the Wavelet Toolbox documentation for more information).
Tree Structure
The Tree structure parameter specifies an asymmetric (or wavelet) tree, as
shown above, or a symmetric structure, as shown below. Note that the
symmetric structure reconstructs a signal that was symmetrically decomposed
by the Dyadic Analysis Filter Bank block (i.e., both the high- and low-frequency
subbands were divided at each level). The asymmetric structure reconstructs a
signal that was asymmetrically decomposed by the Dyadic Analysis Filter
Bank block (i.e., only the low-frequency subbands were divided at each level).
Asymmetric Tree. The asymmetric structure in the first figure (Tree structure
set to
Asymmetric) has n+1 inputs, where n is the Number of levels
parameter value. The sample rate and bandwidth of the output are twice the
sample rate and bandwidth of the top input. The sample rate and bandwidth
of each additional input (except the last) should be half that of the input to the
previous level.
The bottom two inputs (u
n
and u
n+1
) should have the same sample rate and
bandwidth since they are processed by the same level.
Note that in frame-based mode, the change in the sample period of input u
k
is
reflected by its frame size, M
i,k
, rather than by its frame rate.
T
si k 1+,
2T
si k,
=
1 kn<≤
BW
k 1+
BW
k
2
-------------=
1 kn<≤
T
si n 1+,
T
si n,
=
BW
n 1+
BW
n
=
M
ik 1+,
M
ik,
2
------------=
1 kn<≤