GC1115 Datasheet, PDF (60/80 Pages) Texas Instruments – Crest Factor Reduction Processor

GC1115
SLWS144 – FEBRUARY 2005
www.ti.com
POWER_CNT
0x7F (127)
Type: Read/Write Value at RESET: 0xFFFF
The POWER_CNT register determines how many samples are used in each group during power measurement
and during Snapshot RAM operation. During power measurement, the total number of samples observed for
power measurement is POWER_CNT × POWER_CTL[13:0]. During Snapshot RAM histogram operation, the
total number of samples observed for the histogram is POWER_CNT × SNAP_HISTCOUNT. At GC1115 reset,
POWER_CNT = 0xFFFF (65535).
BITS
[15:0]
DESCRIPTION
Number of samples in a power measurement or histogram group (0 to 65535)
Interpolate-by-4 Registers (Addresses 128 – 169)
INTERP_CTL
0x80 (128)
Type: Read/Write Value at RESET: 0x0000
BITS
[1:0]
[15:2]
Interpolator oper-
ation:
Reserved
DESCRIPTION
00: Interp by 2, complex output
01: Interp by 2, f^s/4 enabled, real output
1x: Interp by 4, f^s/4 enabled, real output
NOTE:
To bypass the interp-by-4 stage, clear bit 4 of the CONTROL register, set 0x82 to
0x8000, and clear 0x83 to 0xA9.
INTERP_COEFS 0x82 – 0xA9 Type:
Value at RESET: 0x8000 (0x82), 0x0000 (0x83 – 0xA9)
(130 – 169) Read/Write
Addresses 0x82 to 0xA9 store the interpolation stage’s 40 interpolation coefficients. These coefficients are
accessed even if the interpolation stage is bypassed, i.e. even when bit 4 of CONTROL (0x2) is cleared. GC1115
users must therefore ALWAYS initialize the interpolation coefficients. After RESET, the interpolation coefficients
are initialized for bypass operation (value at address 0x82 = 0x8000; all other interpolation coefficients = 0). The
earlier section entitled Interpolate-by-4 Operation described the required interp-by-4 coefficients during
interpolation.
BITS
[15:0]
DESCRIPTION
Signed, 16-bit interp-by-4 coefficient, from –32768 to +32767
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