mpc823rg Freescale Semiconductor, Inc, mpc823rg Datasheet - Page 491

• Manufacturer Part Number: mpc823rg
• Description: Mpc823 Powerquicc Integrated Communications Processor For Portable Systems
• Manufacturer: Freescale Semiconductor, Inc

16.3.4.1 FIR1–REAL C, REAL X, AND REAL Y. The FIR1 function implements a basic
FIR filter with k real coefficients, real input samples, and real 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.
16.3.4.1.1 Coefficients and Sample Data Buffers. The coefficients vector occupies k
16-bit half-words in memory and C(0) is stored in the first location. The sample input buffer
is a cyclic buffer containing M+1 bytes. Each sample is a 16-bit word 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. Each output is a 16-bit half-word and the new output is stored in
the address that follows the previous output.
Figure 16-13. FIR1 Coefficients and Sample Data Buffers
COEFFICIENTS
{REAL}
X(N)
2K bytes
C(k-1)
C(0)
C(1)
C(2)
Figure 16-12. FIR1 Implementation Example
Freescale Semiconductor, Inc.
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T
T
T
MPC823 REFERENCE MANUAL
{REAL}
C(K-1)
C(0)
C(1)
C(2)
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INPUT SAMPLES
M + 1 bytes
x(N-k+1)
x(N-2)
x(N-1)
x(N)
*
*
*
*
Y n
{REAL}
Y(N)
=
p
k 1
Communication Processor Module
–
=
0
C p X n p
N + 1 bytes
OUTPUT
Y(N-k+1)
Y(N-2)
Y(N-1)
Y(N)
*
*
*
*
*
*
–
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