hsp50214a Intersil Corporation, hsp50214a Datasheet - Page 56

• Manufacturer Part Number: hsp50214a
• Description: Programmable Downconverter
• Manufacturer: Intersil Corporation

POSITION
POSITION
31-10
31-10
BIT
BIT
CONTROL WORDS 64-95: DISCRIMINATOR COEFFICIENT REGISTERS (SYNCHRONIZED TO PROCCLK)
Discriminator FIR
Coefficient
Programmable FIR
Coefficient
FUNCTION
FUNCTION
CONTROL WORDS 128-255: 255 PROGRAMMABLE COEFFICIENT REGISTERS
The discriminator FIR coefficients are 22-bit-two’s complement. If the filter is symmetric, the co-
efficients are loaded from the center coefficient at address 64 to the last coefficient. If the filter
is asymmetric the coefficients C
is number of asymmetric coefficients.
The programmable FIR coefficients are 22-bit-two’s complement. If the filter is symmetric, the
coefficients are loaded from the center coefficient at address 128 to the last coefficient. If the
filter is asymmetric the coefficients C
where N is number of asymmetric coefficients.
Real Filters are computed as:
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
Qout = (Xn-k+1_i * Ck-1_im + Xn-k+1_q * Ck-1_re).
Xn-k+1 Ck1 + Xn-k+2 Ck-2 + ... XnC0),
= (-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
+ (Xn-k+2_i * Ck-2_im + Xn-1+2_q * Ck-2_re).
+ ...
+ (Xn_i
HSP50214A
* C0_im + Xn_q
* C0_im + Xn_i
56
0
to C
0
* C0_re).
N
* C0_re).
to C
DESCRIPTION
DESCRIPTION
are loaded with C
N
are loaded with C
0
in address 64 up to 64+N, where N
0
in address 128 up to 128+N,