ISL5416 Datasheet, PDF (50/71 Pages) Intersil Corporation – Four-Channel Wideband Programmable DownConverter

ISL5416
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TABLE 52. CHANNEL PROCESSING CONTROL (IWA = *001h) RESET STATE = 0x00000000h (Continued)
FUNCTION
AGC GAIN OUTPUT ROUNDING. The AGC gain is rounded to the selected number of bits. The AGC gain word into the rounder is:
E E E E M M M M M M M M M M M M M M.
The AGC gain is 2^E * (1.0 + M / 16384)
EEEE = 0 - 15, MMM...M = 0 - 16383
0 1. M M M M M M M M M M M M M M * 2^(E E E E)
TABLE 54.
FEDCBA 9 8 76 5 43 2 1 0
000 = E E E E M M M M M M M M M M M M ~
001 = E E E E M M M M M M M M Z Z Z Z ~
010 = E E E E M M M M Z Z Z Z Z Z Z Z ~
resolution
96/65536dB
96/4096dB
96/256dB
Z = Zero
All other codes are reserved.
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TABLE 55. NCO CENTER FREQUENCY (IWA = *002h) RESET STATE = 0x00000000h
FUNCTION
CARRIER CENTER FREQUENCY (CCF). The range is -Fs/2 to +Fs/2, where Fs is the input sample rate to the part. The carrier
frequency is: Fc = Fs * CCF / (2^32).
The CCF control is double buffered. The active carrier center frequency register is read at this address.
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TABLE 56. NCO PHASE OFFSET (IWA = *003h) RESET STATE = 0x00000000h
FUNCTION
UNUSED.
PHASE OFFSET. This is the value of the phase offset added to the carrier NCO phase. This can be interpreted as either an unsigned
number with a range from 0 to 2π − (π / 32768) in 65536 steps, or as a signed number with a range of -π to π − (π / 32768) in 65536
steps.
TABLE 57. NCO CENTER FREQUENCY UPDATE (IWA = *004h) RESET STATE = INACTIVE
N/A
FUNCTION
N/A STROBE. A write to this location generates a one-clock-wide strobe that transfers the carrier center frequency written to the holding
register (IWA = *002h) to the active register. The transfer can also be caused by a SYNCI signal (see IWA = *000h). The contents
of the active register are read at location IWA = *002h.
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19
TABLE 58. NCO/MIXER/CIC CONTROL (IWA = *005h) RESET STATE = 0x00000000h
FUNCTION
MAXIMUM EXPONENT SHIFT SATURATION LEVEL. The maximum allowed shift factor from the input A/D range control block and
the exponent from the input bus. If the sum exceeds this value, it will be saturated at this value. This is forced to 111 if the uP test
register is selected as the input source.
FORCE ZERO FEEDBACK. Set to 1 to force NCO phase accumulator feedback to 0. (Provided for test)
CLEAR FEEDBACK ON UPDATE.
1 = clear NCO phase accumulator on frequency load/update (for synchronizing the NCO phase of multiple channels).
0 = phase continuous frequency updates.
RESERVED. Set to 0.
CIC BASE SHIFT FACTOR. The shift factor (exponents) from the input and the range control block are added to this value.
RESERVED. Set to 0.
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