ISL5416_14 Datasheet, PDF (52/71 Pages) Intersil Corporation – Four-Channel Wideband Programmable

ISL5416
TABLE 61. AGC CONTROL, MEAN/MEDIAN, DELAY, MODE (IWA = *008h) RESET STATE = 0x00000000h (Continued)
P(31:0)
FUNCTION
6
LOOP GAIN 2 MEAN/MEDIAN.
1 = AGC settles to mean of the signal if LG2 is selected.
0 = AGC settles to median of the signal.
5
uP LOOP GAIN SELECT. Set to:
1 = loop gain 2.
0 = loop gain 1.
4
uP LOOP GAIN CONTROL. Set to:
1 = uP loop gain select.
0 = counter controlled loop gain select.
3
DISABLE LOOP FILTER UPDATE. Set to:
1 = disable loop filter (holds the last value, the uP can load).
0 = normal AGC operation.
2
SAMPLED MODE.
1 = continuous forward gain updates.
0 = the forward gain held during the interval count (when loop gain 1 is used). The forward gain is continuously updated after the
interval count (when loop gain 2 is used).
1
ENABLE DELAY. Set to:
1 = enable delay
0 = no delay
NOTE: Delay must be enabled for Sampled Mode.
0
RESERVED. Set to 0.
TABLE 62. CONTROL BIT SETTINGS FOR AGC MODES
AGC MODE
IWA=*001h
IWA = *008h
BIT 20
BIT 4
BIT 2
BIT 1
CONTINUOUS UPDATE
µP controls loop gain
0
1
1
0
CONTIUOUS WITH DELAY
0
1
1
1
TIMED LOOP GAIN SELECTION
1
0
1
0
TIMED WITH DELAY
1
0
1
1
SAMPLED GAIN UPDATES
(always with delay)
1
0
0
1
P(31:0)
31:16
15:0
TABLE 63. THRESHOLD (SET POINT) (IWA = *009h) RESET STATE = 0x00000000h
FUNCTION
UNUSED.
SET POINT. Bit weights:
2^
2 1 0. 1 2 3 4 5 6 7 8 9 0 1 2 3, 2⁰ is the full scale vector magnitude on one axis before the magnitude computation gain is applied.
Note: There is a gain in the magnitude computation prior to the threshold compare. The gain versus number of clocks is:
CLOCKS
GAIN
16
1.64676
8
1.647
4
1.642
3
1.630
2
1.581
The set point should be programmed to the desired level times the magnitude gain.
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52