Peak Chroma; Color Kill - Analog Devices ADV7850 Hardware Manual

Function
sdp_pw_rec_rate[11:0]
0x0F[3:0]
0x10[7:0]

Peak Chroma

6.6.4
sdp_pc_en, Addr 90 (SDP), Address 0x05[6]
This control is used to enable the peak-color chroma gain feature. Peak-color chroma overrides and reduces the gain of the chroma
AGC if the chroma signal path becomes larger than a set threshold. Peak chroma can only act to reduce the AGC gain. When there are
no more violations of the peak white threshold, the peak chrome algorithm allows the chroma AGC to restore the gain (based on the
synchronization depth). The recovery rate of the AGC gain is set by the peak chroma recovery register.
Function
sdp_pc_en
1 
0
sdp_pc_rec_rate[11:0], Addr 90 (SDP), Address 0x0F[7:4]; Address 0x11[7:0]
This control is used to adjust the peak chroma gain recovery speed, that is, the speed at which the chroma gain is increased following a
gain reduction due to peak color violation. A larger value corresponds to a faster speed.
Function
sdp_pc_rec_rate[11:0]
0x0F[7:4]
0x11[7:0]

Color Kill

6.6.5
Color kill mode is the feature of the ADI decoder that allows the removal of chroma when the color burst level of the input is poor. This
feature is especially useful when inputting weak-signal tuner signals.
sdp_ckill_en, Addr 90 (SDP), Address 0x07[7]
This control is used to enable the color kill feature.
Function
sdp_ckill_en
1 
0
sdp_ck_low_thr[6:0], Addr 90 (SDP), Address 0x07[6:0]
This control is used to set the color kill low threshold. If the burst power is below this threshold, it enters color kill mode.
Function
sdp_ck_low_thr[6:0]
00001011 
sdp_ck_high_thr[7:0], Addr 90 (SDP), Address 0x08[7:0]
This control is used to set the color kill high threshold. If the burst power is above this threshold, it enters color kill mode.
Rev. A May 2012
Description
sdp_pw_rec_rate[12:8]
sdp_pw_rec_rate[7:0]
Description
Enable peak color chroma gain
Disable peak color override of chroma gain
Description
sdp_pc_rec_rate[12:8]
sdp_pc_rec_rate[7:0]
Description
Enable color kill feature
Disable color kill feature
Description
Color kill low threshold
86
ADV7850