Analog Devices Advantiv ADV7604 Hardware Manual page 240

The ADV7604 itself does not provide a peak-white AGC. It merely monitors the clamped and
gained input signal for the largest video code encountered in each of the three channels and presents
this video code for readback via the I
Notes:
• The measurement is taken on a field basis (from one vertical synchronization to the next).
The read out at any time refers to the previous field, not necessarily the current one.
• The tap-off point for the measurement is right after the gain multipliers. This means that
clamping and AGC/manual gain have an affect on the results.
• The peak video readback is calculated according to
(Peak video ampl - Clamp level) * (V_to_CODE) * GAIN * (1/8)
V_to_CODE = Voltage to ADC code conversion factor (V_to_Code also depends on AFE settings
such as PGA gain)
GAIN = AGC gain OR user applied gain OR automatic gain in non embedded sync mode
PKV_CHA[9:0], Peak Video Value on Channel A Read Back , CP Map, Address 0xED, [5:4];
Address 0xEE, [7:0]
Function
PKV_CHA[9:0]
xx xxxx xxxx
PKV_CHB[9:0], Peak Video Value on Channel B Read Back , CP Map, Address 0xED, [3:2];
Address 0xEF, [7:0]
Function
PKV_CHB[9:0]
xx xxxx xxxx
PKV_CHC[9:0], Peak Video Value on Channel C Read Back , CP Map, Address 0xAD, [1:0];
Address 0xB0, [7:0]
Function
PKV_CHC[9:0]
xx xxxx xxxx
Rev. F August 2010
2
C. There is no averaging or filtering before the peak detection.
P
P
Peak active video readback value =
Equation 12: Peak Active Video Readback Value
Description
Maximum encountered signal level during active video on channel A
within the last field
Description
Maximum encountered signal level during active video on channel B
within the last field
Description
Maximum encountered signal level during active video on channel C
within the last field
Equation
240
12.
ADV7604