hsp50214 Intersil Corporation, hsp50214 Datasheet - Page 50

• Manufacturer Part Number: hsp50214
• Description: Programmable Downconverter
• Manufacturer: Intersil Corporation

POSITION
POSITION
POSITION
POSITION
31-10
31-10
31-0
N/A
BIT
BIT
BIT
BIT
CONTROL WORDS 64-95: DISCRIMINATOR COEFFICIENT REGISTERS (SYNCHRONIZED TO PROCCLK)
AGC Load
Reserved
Discriminator FIR
Coefficient
Programmable FIR
Coefficient
FUNCTION
FUNCTION
FUNCTION
FUNCTION
CONTROL WORDS 128-255: 255 PROGRAMMABLE COEFFICIENT REGISTERS
CONTROL WORD 26: LOAD AGC GAIN (SYNCHRONIZED TO PROCCLK)
CONTROL WORD 27: TEST REGISTER (SYNCHRONIZED TO CLKIN)
Writing to this location generates a strobe to load the AGC loop accumulator with bits (15:5) to
the master registers. These bits are loaded into the MSBs of the AGC loop filter accumulator
with bits (15:12) mapping to the shift (exponent) control bits and bits (11:5) mapping to the mul-
tiplier (mantissa) bits. Bits (11:5) represent a binary mantissa mapped to the linear gain as:
01.XXXXXXX. See AGC Section.
A fixed value 0000 0010 0111 1000 [0278]
0000 0010 0111 1010 [027A]
7FFF.
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
* C0_im + Xn_q
HSP50214
* C0_im + Xn_i
50
HEX
0
to C
is loaded here for setting the Sin/Cos generator outputs to
0
* C0_re).
N
* C0_re).
to C
DESCRIPTION
DESCRIPTION
DESCRIPTION
DESCRIPTION
are loaded with C
HEX
N
are loaded with C
is loaded here for normal operation. A fixed value
0
in address 64 up to 64+N, where N
0
in address 128 up to 128+N,