mpc823rg Freescale Semiconductor, Inc, mpc823rg Datasheet - Page 512

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mpc823rg

Manufacturer Part Number
mpc823rg
Description
Mpc823 Powerquicc Integrated Communications Processor For Portable Systems
Manufacturer
Freescale Semiconductor, Inc
Datasheet
Communication Processor Module
16.3.4.7 MOD–REAL SIN, REAL COS, COMPLEX X, AND REAL/COMPLEX Y. The
MOD function implements a basic modulator function with a modulation table composed of
{cos nT, sin nT} pairs, complex input samples, and real outputs. 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.
16.3.4.7.1 Modulation Table and Sample Data Buffers. The modulation table is
composed of 16-bit cosine and sine pairs that occupy K+1 bytes in memory. The sample
input buffer is a cyclic buffer containing M+1 bytes. Each sample is a pair of 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 contain N+1 bytes and the new
output is stored in the address that follows the previous output. The output buffer can be real
or complex, depending on the X bit in the function descriptor.
MODULATION TABLE
K + 1 bytes
cos q
cos q
cos q
sin q
sin q
sin q
*
*
1
2
n
1
2
n
Figure 16-25. MOD Table and Sample Data Buffers
IMAG Y n
REAL Y n
Figure 16-24. MOD Implementation Example
Freescale Semiconductor, Inc.
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{COMPLEX}
INPUT SAMPLES
imag {x(n-k+1)}
real {x(n-k+1)}
imag {x(n-2)}
imag{x(n-1)}
M + 1 bytes
real{x(n-2)}
real{x(n-1)}
X(n)
imag{x(n)}
=
real{x(n)}
=
MPC823 REFERENCE MANUAL
REAL X n
REAL X n
*
*
*
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cos nT, sin nT
{REAL}
sin
cos
nT
nT
OUTPUT (REAL)
+
real{Y(n-K+1)}
real{Y(n-2)}
N + 1 bytes
IMAG
real{Y(n-1)
real{Y(n)}
IMAG X n
{REAL OR COMPLEX}
*
*
*
*
*
X n
Y(n)
cos
sin
nT
nT
OUTPUT (COMPLEX)
imag{Y(n-k+1)}
real{Y(n-k+1)}
imag{Y(n-2)}
imag{Y(n-1)}
real{Y(n-2)}
real{Y(n-1)}
N + 1 bytes
imag{Y(n)}
real{Y(n)}
*
*
*
*
*
MOTOROLA

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