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Cable selection between DS30BA101 and DS30EA101

Daisuke Maeda
Guru 20035 points
Other Parts Discussed in Thread: DS30EA101, DS90UB928Q, DS30BA101

DS30EA101 datasheet describes in the AC Electrical Characteristics the total jitter and the test conditions. When 75ohm coaxial cable (RG59) is used, it seems the cable length can be up to 100 meters at 3.125 Gbps.

In this test condition, What is the maximum cable loss? Are there the details of the cable specification?

Our customer is using the coaxial cable of 60 meters and connecting DS90UB925Q and DS90UB928Q via DS30BA101 and DS30EA101, but there are errors in the video output. If the total jitter between DS30BA101 and DS30EA101 is 0.3UI, the jitter should not be a cause of the errors because the DS90UB928Q has the jitter tolerance of approximately 0.6UI. When the DS90UB928Q is set to LCBL mode that affects the input adaptive equalizer (AEQ), the errors seem to be improved.

I am concerned that the cable quality is bad. About the relationship between the cable length, the data rates, the cable loss or jitter, are there the test results for the cables of various grade?

Best regards,

Daisuke

 

  • 0
    TI__Guru* 93670 points
    Greetings Maeda-San,

    DS30EA101 is a multi-stage adaptive cable equalizer. Based on the cable insertion loss it automatically sets the equalizer gain. The equalizer gain can vary from 0dB, in bypass mode, to about 48dB of gain at 1.6GHz. So as long as the cable insertion loss is within this range, DS30EA101 can compensate for this loss with typical 0.55UI or lower jitter.

    Please note DS90UB928Q uses back channel. Could you please let us know if this is enabled or disabled?

    Also, it would be a good to get a copy of the DS30EA101 and DS30BA101 schematic and scope shot at the output of the DS30BA101 and DS30EA101 devices.

    Regards,,nasser
  • 0 in reply to Nasser Mohammadi
    Guru 20035 points

    Hi Nasser-san,

    Thank you for your reply. Sorry for my late reply.

    Our customer used an incompatible cable for reduction in cost.

    Best regards,

    Daisuke