User`s guide

Dyadic Analysis Filter Bank
5-154
In frame-based mode, the sample period of output y
k
is reflected by its frame
size, M
o,k
, rather than by its frame rate.
Sample-Based Operation
An M-by-N sample-based matrix input is treated as M∗N independent
channels, and the block filters each channel independently over time. The
output at each port is the same size as the input, one output channel for each
input channel. As described earlier, for the asymmetric tree structure, each
output port has a different sample period.
The figure below shows the input and output sample periods for a 64-channel
sample-based input to a three-level filter bank. The input has a period of 1, so
the fastest output has a period of 2.
Frame-Based Operation
An M
i
-by-N frame-based matrix input is treated as N independent channels,
and the block filters each channel independently over time. The input frame
size M
i
must be a multiple of 2
n
, and n is the number of filter bank levels. For
example, a frame size of 8 would be appropriate for a three-level tree (2
3
=8).
The number of columns in each output is the same as the number of columns
in the input.
Each output port has the same frame period as the input. The reduction in the
output sample rates results from the smaller output frame sizes, as shown in
the example below for a four-channel input to a three-level asymmetric tree.
M
ok,
M
i
2
n
-------
1 k 2
n
≤≤()=
T
si
= 1
T
so
= 2
T
so
= 4
T
so
= 8
T
so
= 8