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

Observe with an oscilloscope, we can see some abnormal pulse in the video signal.

But I don't know why there is such a pulse

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 

Note:

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.   

Thanks,

Poornima

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 

Note:

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.   

Thanks,

Poornima

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