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evgenis1
Advisor
Advisor
9,189 Views
Registered: ‎12-03-2007

Interpreting GTY Ibert eye scan results

Hi,

 

I'm having a problem interpreting GTY Ibert eye scan results. Attached are three scans:

 

  1. Good eye scan: PRBS31, DFE=on   (eye1.jpg)

        Looks as expected.

 

  2. PRBS31, DFE=off (eye4.jpg) 

      I cannot explain why the eye gets out of vertical borders.

 

  3. Slow clock data pattern, DFE=on (eye2_slow_clock.jpg)

     On the scope I see a low-jitter shape resembling sine wave. But Ibert eye scan produce this strange triangle shape.

 

Thanks,

Evgeni

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eye1.jpg
eye4.jpg
eye2_slow_clock.jpg
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dwisehart
Scholar
Scholar
9,176 Views
Registered: ‎06-23-2013

Top looks fine. Middle one would probably drop back if you pull back the gain setting. Bottom one looks like it has DC offset.
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bfung
Explorer
Explorer
2,797 Views
Registered: ‎03-27-2017

@evgenis1 Did you ever find a solution for the second eye scan (with the eye extending past the vertical axis)? I'm currently running into the same problem!

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evgenis1
Advisor
Advisor
2,793 Views
Registered: ‎12-03-2007

@bfung

No, I have not. 

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bfung
Explorer
Explorer
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Registered: ‎03-27-2017

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