Why there as a voltage offset present on the output of video decoder.
Most likely is because clamping is incorrect or gain is set incorrectly. This issue can happen sometimes on the nonstandard scripts
1. On a scope – ensure what is the level voltage of blanking level. If blanking voltage level is correct – this means, that decoder clamps correctly, and only offset and gain should be done to the decoder. Below is an example of the offset/gain control.
42 73 D2 ; Enable Manual Gain and set CH_A gain
42 74 94 ; Set CH_A and CH_B Gain;
42 75 A5 ; Set CH_B and CH_C Gain
42 76 29 ; Set CH_C gain
42 77 00 ; Set offset to 11d
42 78 B0 ; Set offset to 11d
42 79 2C ; Set offset to 11d
42 7A 0B ; Set offset to 11d
If this does not help – please try adjusting clamping (point 4)
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