Eye diagram failure

[Altera_Forum]

Hi, 

 I am using Altera V GT device for 10.3125 Gbps XFI link,with 322MHZ reference clock.The measured eye at my RX seems very bad and its not same as simulated results.We tried changing pre emphasis settings and could see slight improvement. However the eye with any of the Vod and Tap combination violating the XFI specification.  My on board clock looks clean.  Anything to do with PLL supply.slew rate and CDR?  Regards bala

[Altera_Forum]

Have you checked the test coupons with a TDR?

[Altera_Forum]

No,but we measured impedance and its 99 ohm.

[Altera_Forum]

Hi Bala, 

 Generally the eye diagram at the RX would have significant dependency on the board setup as well. You could do a comparison between the TX output eye vs RX output eye. If the TX eye is clean, then you would need to further look into the board setup to see if there is any improvement area.   By the way, you may try with RX equalization to see if it helps.