User`s guide

Time-Varying Lattice Filter
5-438
5Time-Varying Lattice Filter
Purpose Apply a variable lattice filter to the input.
Library Filtering / Filter Designs
Description The Time-Varying Lattice Filter block applies a moving average (MA) or
autoregressive (AR) lattice filter to the top input (
In). The filter reflection
coefficients are specified by the vector input to the
MA or AR port, and can vary
with time.
An M-by-N sample-based matrix input to the
In port is treated as M∗N
independent channels, and an M-by-N frame-based matrix input is treated as
N independent channels. In both cases, the block filters each channel
independently over time, and the output has the same size and frame status as
the input.
Filter Type
The Filter type parameter specifies whether the filter is an all-zero
(FIR or MA) filter or all-pole (AR) filter.
•
All-zero
The block constructs an nth order MA filter using the n reflection coefficients
contained in the vector input to the
MA port.
k = [k(1) k(2) ... k(n)]
•All-pole
The block constructs an nth order AR filter using the n reflection coefficients
contained in the vector input to the
AR port.
k = [k(1) k(2) ... k(n)]
For both designs, the coefficient vector inputs can change over time to alter the
filter’s response characteristics during the simulation.
Initial Conditions
In its default form, the filter initializes the internal filter states to zero, which
is equivalent to assuming past inputs and outputs are zero. The block also
accepts optional nonzero initial conditions for the filter delays. Note that the
number of filter states (delay elements) per input channel is
length(k)