EVAL-ADV7842-7511 Noise Interference lines

Hi, I have a EVAL-ADV7842-7511 Board which I'm using to decode CVBS signal from a Laserdisc player.

I have an issue where I'm seeing faint diagonal lines across the image. These are present on all of the input formats 10Bit, 24Bit and 36Bit and is also present on the s-video input. 

It it looks almost like interference. I've tried multiple cables and players and all produce the same results.

Any idea what is causing this?

many thanks

ken

Parents
  • 0
    •  Analog Employees 
    •  Super User 
    on Jan 26, 2017 6:15 PM

    The ADV7842 was originally designed to handle VCR outputs.  Your laser disk player pre-dates VCRs.  The laser disk player might be generating some kind of noise which will not show on composite TVs of their day.  The 3D comb filter might extenuate this noise to the point where it can be seen on today's high quality TVs.

    The TBC option was designed to handle frame timing jitter issues VCRs had.

    It's OK to turn off TBC and 3D comb.  

    The SW repeater is embedded code that configures the operation of the board.  In HDMI definition 'repeater' is a function that handle EDID reads from the sink and forwards them to the source.  It also handles all the HDCP requirements of moving keys up stream.  The eval board you have allows you to override the repeater code with scripts.

    Your laser disk player is composite only so you don't have to worry about HDCP keys.  

Reply
  • 0
    •  Analog Employees 
    •  Super User 
    on Jan 26, 2017 6:15 PM

    The ADV7842 was originally designed to handle VCR outputs.  Your laser disk player pre-dates VCRs.  The laser disk player might be generating some kind of noise which will not show on composite TVs of their day.  The 3D comb filter might extenuate this noise to the point where it can be seen on today's high quality TVs.

    The TBC option was designed to handle frame timing jitter issues VCRs had.

    It's OK to turn off TBC and 3D comb.  

    The SW repeater is embedded code that configures the operation of the board.  In HDMI definition 'repeater' is a function that handle EDID reads from the sink and forwards them to the source.  It also handles all the HDCP requirements of moving keys up stream.  The eval board you have allows you to override the repeater code with scripts.

    Your laser disk player is composite only so you don't have to worry about HDCP keys.  

Children
No Data