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LMH0074: Valid SDI signal input condition for carrier detect

K. Sasaki14
Guru 10200 points
Part Number: LMH0074

I would like to know valid SDI input condition for carrier detect.

I think there is input swing level threshold for carrier detect asserted and de-asserted.

Please let me know the both threshold value.

Best Regards,
Kohei Sasaki

  • 0
    TI__Guru* 93670 points
    Greetings,

    Valid SDI input signal for carrier detect is at a launch amplitude of 700mV at minimum and 400m of B1694A cable.

    LMH0074 equalizes 400m of B1694A at SD SDI rate. This means LMH0074 has about 30dB gain at 135MHz nyquist frequency.

    Regards,,nasser
  • 0 in reply to Nasser Mohammadi
    Guru 10200 points
    Nasser-san,

    Thank you for you reply.
    I have additional question.
    Is there hysteresis between carrier detect assert and de-assert level? Please let me know the hysteresis level if there is.

    Best Regards,
    Kohei Sasaki
  • 0 in reply to K. Sasaki14
    TI__Guru* 93670 points

    Hi Sasaki-San,

    1). There is hyteresis for carrier detect to prevent carrier detect signal from bouncing - being asserted and in-asserted. However, I don't know the actual level.

    2). Additionally there is a timer as well. that determines length or time when carrier is being asserted or in-asserted. This is done to make sure carrier detector is not triggered by noise and provides some level of hyteresis as well.

    Regards,,nasser