Manual Gain Control - Analog Devices Advantiv ADV7604 Hardware Manual

10.3.4 Manual Gain Control

The automatic gain control (AGC) can be completely disabled by setting the gain control block into
a manual mode. By setting the
longer taken from the AGC, but are replaced by three dedicated I
Using these factors with the HSD_FB[9:0] register, it is possible to implement an off-chip AGC if
desired. The range for the gain is [0...3.999]. The registers A_GAIN[9:0], B_GAIN[9:0], and
C_GAIN[9:0] are in 2.8 binary format and can be set as shown in
where:
≤ GAIN <
0 4
( )
is the floor function that returns the largest integer not greater than its input parameter
floor
X refers to A, B, and C
Example :
GAIN_MAN Manual Gain Control Enable , CP Map, Address 0x73, [7]
Function
GAIN_MAN
0
1
A_GAIN[9:0] Manual Gain Value for Channel A , CP Map, Address 0x73, [5:0]; Address 0x74,
[7:4]
Note : To change the A_GAIN[9:0] value, registers 0x73 and 0x74 must be written to in this order
2
with no other I C access in between.
Function
A_GAIN[9:0]
xx xxxx xxxx
0x100
Rev. F August 2010
GAIN_MAN bit, the gain factors for channels A, B, and C are no
_ [ : 9
X GAIN
Equation 10: CP Manual Gain
Example Gain
dec
B
0.5
0.98887
2.5
Description
Gain factors for all three channels are generated by the AGC
The gains for the three channels are set by A_GAIN[9:0], B_GAIN[9:0],
and C_GAIN[9:0]
Description
Sets the manual gain for the signal in channel A
Default value
2
C registers.
Equation
(
= ×
] 0 256
floor GAIN
A_GAIN[9:0]
B
0x80
0xFD
0x280
233
10.
)
ADV7604