Pentek 6210 Operating Manual page 105

CONTROL WORDS 64-95: DISCRIMINATOR COEFFICIENT REGISTERS (SYNCHRONIZED TO PROCCLK)
BIT
POSITION FUNCTION
31-10 Discriminator FIR
Coefficient
CONTROL WORDS 128-255: 255 PROGRAMMABLE COEFFICIENT REGISTERS
BIT
POSITION FUNCTION
31-10 Programmable FIR
Coefficient
3-57
HSP50214B
The discriminator FIR coefficients are 22-bit-two's complement. If the filter is symmetric, the coefficients
are loaded from the center coefficient at address 64 to the last coefficient. If the filter is asymmetric the
coefficients C to C are loaded with C
0 N
coefficients.
The programmable FIR coefficients are 22-bit-two's complement. If the filter is symmetric, the coeffi-
cients are loaded from the center coefficient at address 128 to the last coefficient. If the filter is asym-
metric the coefficients C to C
0
asymmetric coefficients.
Real Filters are computed as:
Xn-k+1 Ck1 + Xn-k+2 Ck-2 + ... XnC0),
where C0 is the coefficient in address 128 and Xo is the oldest data sample.
Complex filters outputs are computed as follows:
Xn is the most recent data sample.
k is the number of samples = number of (complex) taps.
C0_re is the coefficient loaded into CW128.
C0_im is the coefficient loaded into CW129.
The convolution starts with the oldest data, times the last complex coefficient, and ends with the newest
data, times the first complex coefficient loaded.
Iout = (-Xn-k+1_q * Ck-1_im + Xn-k+1_i * Ck-1_re).
+ (-Xn-k+2_q * Ck-2_im + Xn-1+2_i * Ck-2_re).
+ ...
+ (-Xn_q * C0_im + Xn_i
Qout = (Xn-k+1_i * Ck-1_im + Xn-k+1_q * Ck-1_re).
+ (Xn-k+2_i * Ck-2_im + Xn-1+2_q * Ck-2_re).
+ ...
+ (Xn_i * C0_im + Xn_q
DESCRIPTION
in address 64 up to 64+N, where N is number of asymmetric
0
DESCRIPTION
are loaded with C in address 128 up to 128+N, where N is number of
N 0
* C0_re).
* C0_re).