HSP50214 Datasheet, PDF (22/54 Pages) Intersil Corporation – Programmable Downconverter

HSP50214
.
TABLE 9. BIT WEIGHTING FOR AGC LOOP FEEDBACK PATH
AGC
ACCUM
BIT
POSITION
GAIN
ERROR
INPUT
GAIN
ERROR
BIT
WEIGHT
AGC LOOP
FILTER GAIN
(MANTISSA)
AGC LOOP
FILTER
GAIN
MULTIPLIER
(OUTPUT)
SHIFT
=0
SHIFT
=4
SHIFT
=8
SHIFT
= 15
AGC
OUTPUT
AND AGC
LIMITS BIT
WEIGHT
AGC GAIN
RESOLUTION
(dB)
31
2
2
2
20
30
2
2
2
2E3
48
29
2
2
2
2E2
24
28
2
2
2
2E1
12
27
12
=2
2
2
2
2
2E0
6
26
25
11
10
.^{= 1}
=0
0.
.¹
0
2
2
2
2
2
2
.¹
0
M
M
-1
-2
3
1.5
24
9
=1
x
1
2
2
2
1 M -3
0.75
23
8
=2
x
2
2
2
2
2 M -4
0.375
22
7
=3
x
3
2
2
2
3 M -5
0.1875
21
6
=4
x
4
2
2
2
4 M -6
0.09375
20
5
=5
5
2
2
2
5 M -7
0.04688
19
4
=6
18
3
=7
6
7
2
2
2
2
.¹
0
6 X -8
7
-9
0.02344
0.01172
17
2
=8
8
2
2
1
8
-10
0.00586
16
1
=9
9
2
2
2
9
-11
0.00293
15
0
= 10
14
10
11
2
2
.¹
0
3
4
10
11
-12
0.00146
-13
0.000732
13
12
2
1
5
12
-14
0.000366
12
13
2
2
6
13
-15
0.000183
11
10
14
.¹
0
3
4
7
14
8
G
-16
0.0000916
-17
0.0000458
9
1
5
9
G
-18
0.0000229
8
2
6
10
G
-19
0.0000114
7
3
7
11
G
-20
0.00000572
6
4
8
12
G
-21
0.00000286
5
5
9
13
G
4
6
10
14
G
3
7
11
G
G
2
8
12
G
G
1
9
13
G
G
0
10
14
G
G
AGC Response_Max = Input(Cart/PolarGain)(Error Det Gain)(AGC Loop Gain_Max)(AGC Output Weighting).
AGC Response_Max = (1)(1.64676)(2^-0)(1)(0.75dB) ~ 1.23dB/symbol time.
AGC Response_Min = (1)(1.64676)(2^-15)(1)(0.75dB) ~ 0.00004dB/symbol time.
Thus, the expected range for the AGC rate is ~ 0.00004 to 1.23dB/symbol time.
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