Motorola MPC823e Reference Manual page 504

Communication Processor Module
16.3.4.4 FIR5–COMPLEX C, COMPLEX X, AND COMPLEX Y. The FIR5 function
implements a basic FIR filter with k complex coefficients, complex input samples, and
complex output. The input data is in a circular buffer with size M+1 and the output data is in
a circular buffer with size N+1. The FIR5 only uses other input data samples to implement
a fractionally spaced equalizer.
X(N)
{COMPLEX}
16.3.4.4.1 Coefficients and Sample Data Buffers. The coefficients vector occupies k
pairs of 16-bit half-words (real and imaginary components) in memory and C(0) is stored in
the first location. The sample input buffer is a cyclic buffer containing M+1 bytes. Each input
sample is two 16-bit half-words (real and imaginary components) and the new sample is
stored in the address that follows the previous sample. The output buffer is a cyclic buffer
that contains N+1 bytes and the new output is stored in the address that follows the previous
output.
16-50
C(0)
{COMPLEX}
T
C(1)
T
C(2)
T
C(K-1)
Figure 16-18. FIR5 Implementation Example
MPC823e REFERENCE MANUAL
∑
Y(N)
{COMPLEX}
k 1
∑
Y n ( )
=
p
–
C p ( )X n p ( )
–
= 0
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