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HDMI Pre-emphasis? (DS15BR400?)

David Wang11
Expert 7400 points
Other Parts Discussed in Thread: DS15BR400, DS22EV5110, DS34RT5110, DS16EV5110A

HDMI uses TMDS signaling, and I am looking for a part that has a pre-emphasis and de-emphasis. I was looking at the DS15BR400 will has pre-emphasis but it shows that it is used for LVDS signaling. Since the DS15BR400 has 4 separate LVDS channels, would it be possible to feed the TMDS signaling (R,G,B clock) diff pairs into each channel or is that not possible due to votlage level thresholds, etc...?

Are there any parts that have equalization/pre-emp/de-emp for HDMI signaling?

  • 0
    TI__Expert 3050 points

    Hi,

    Have you looked at the DS22EV5110 or the DS34RT5110?

    Mike Wolfe

    DPS APPS / SVA

  • 0 in reply to Mike Wolfe
    TI__Expert 7400 points

    Thanks for the fast response. I did look at the DS16EV5110A with is an input equalization. The reason why I ask about the pre-emphasis is because the receiver side (in which the TMDS signals are being routed to) there is space constraints, so by having the pre-emphasis network on the transmitter side would be the same as having an equalizer on the receiver side.

    But I think the problem resides in which HDMI protocol is being used. From what I can see HDMI 1.2 and below does not allow pre-emp.

    Would you have any insights about a solution for this?

    Also is it more common to see a de-emphasis or a pre-emphasis on the transmitter side for HDMI applications?

  • 0 in reply to David Wang11
    TI__Expert 3050 points

    Hi,

    At these data rates it is more common to see de-emphasis rather than pre-emphasis. Both transmit signal conditioning techniques set out to do the same thing: compensate for ISI due to the channel loss. Pre-emphasis adds energry to high frequency portions of your data stream. De-emphasis reduces the energy in the low frequency areas of your data stream.

    De-emphasis has become more popular in higher data rate applications because it does not add energy to high frequency data content, like pre-emphasis, which means that there is no increase in emmisions for EMI concerns.

    Mike Wolfe

    DPS APPS / SVA