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ADV7343 ED/HD TEST PATTERNS can not detect by the monitor

Hi team.

we went to use ADV7343 to generate SD and HD video synchronous. The SD video output is OK, but we get problem in the HD video. So we use HD only mode to do some test.

we use ADV7343 to generate a 1080i/30 video to the monitor. But the monitor can not detect and lock the signal.

So we try to output the ED/HD TEST PATTERNS in the ADV7343 to the monitor. The problem is same.

We sent 74.25MHz to the CLKIN_A,and configure the ADV7343 like the datasheet.

{0x56, 0x00, 0x1c}

{0x56, 0x01, 0x10}

{0x56, 0x30, 0x68}

{0x56, 0x31, 0x05}

we can see the video signal and the sync signal in G channel, but the R and B channel is 1.4V.

we don't know was wrong in here.

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  • Hi,

      Generally the test pattern generator should totally overwrite any incoming video stream.

    1) Ensure grounding, power and decoupling are solid and not introducing any noise.
    2) Make sure power to EXT_LF1, 2 PLL filters are very clean and well filtered.
    3) Disconnect the source and see if the noise is still present on the output video.
    4) Check the routing to make sure the digital lines are not coupling into the DAC outputs and their output buffers.

        It might be a layout / grounding issue. Please ensure with that.

    Also  Please cross check with reference schematic which is available at  ADV734x Design Support Files 


    ED Test Pattern- 27Mhz clock signal must be applied to the CLKIN pin.

    HD Test Pattern- 74.25MHz clock signal must be applied to the CLKIN pin.   



  • Thank you very much. The Problem is solved. The abnormal pulse is come from the monitor.