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ADV7611 at resolution 1920 1080 60Hz has some noise

Category: Hardware
Product Number: ADV7611


i have a board which uses an ADV7611 and ADV7125 to confert a source signal from HDMI to a VGA RGB 24bpp. The board is working fine for all supported monitor resolution, but 1080p, which has some noise in the image. I need to fix and work with this resolution.

It seems that resolution 1080p (1920x1080@60hz) is supported from ADV7611 devices. The pixel clock is of the incoming signal is 148.5MHz. Reading HDMI registers inside ADV7611, seems that the incoming signal is correctly detected. TMDS_PLL_LOCKED is 1. VERT_FILTER_LOCKED is 1. DE_REGEN_FILTER_LOCKED is 1. FIELD0 and FIELD1 heigths have the correct values, but in the monitor i see noise aroud the image borders, and in general. Can you help to identify what kind of problem is this?

I have started from script 6-1f to configure device.

Kind Reagrds


on May 5, 2023 9:51 AM in reply to PoornimaSubramani

One other issue to watch for is the bandwidth of the scope you are using to measure the clock frequency with.  If it is only a 200MHz scope then it will start attenuating the signal and turn it into a sinewave.

The DLL adjustment needs to be done a the fastest format and will often fix noise issues that don't appear at slower formats.  Each design might need different adjustments however once found it should be baked into the configuration and good for the entire product's production run.