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undocumented TVP5147M1 I2C register for slicer level control?

Ed Walker
Prodigy 5 points
Other Parts Discussed in Thread: TVP5147M1

Hello legacy video converter forum.

For some time we have had an issue with the legacy TVP5147M1 Video Decoder.

We have a product design which transmits sensor data using NABTS Teletext encoding in standard NTSC video.

Recent tests appear to show the teletext data is being sliced at or near the video pedestal.

Is there an undocumented TVP5147M1 I2C register for slicer level control? 

Your help is appreciated.

  • 0
    Prodigy 5 points

    FYI when using TVP5147M1 teletext for data transmission.

    A teletext signal has amplitude of > 75 IRE has significant BER - our signal was at 80 IRE.

    It was assumed that the teletext signal would be degraded by a long cable run (500+ ft) and a higher amplitude would increase the slice margins.

    Apparently AGC in the TVP brings the signal back to 1V video and the teletext signal input is overloaded.