mpc823rg Freescale Semiconductor, Inc, mpc823rg Datasheet - Page 512

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

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.
For More Information On This Product,
{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
*
*
*
Go to: www.freescale.com
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