04-25-2019 09:18 AM
In our project we are using a Kintex Ultrascale to receive data at 1.2Gbps (8b10b encoded, custom protocol) with GTH transceivers. We noticed that due to some activity on the data source electronics, sometimes we see a lot of 8b10b errors, which were traced back to phase changes in the data source.
So my question first of all is how well and fast the CDR in the GTH transceivers RX can track the phase of the incoming signal? And the second question then of course is what parameters can be changed to improve the resilience to phase changes in the source
04-25-2019 09:35 AM
If they really are phase changes in the data due to interferance,
that are causing 8:10 decoding errors,
then you need to either add error protection to the protocole, or better , fix the problem.
04-25-2019 10:29 AM - edited 04-25-2019 10:29 AM
You can play with the SSC and PPM settings on the first page of the GT wizard to see if there are settings that give you more margin on this channel. I'm sure they can help some but I doubt it would be a solution. I've also seen forward error correction added to designs to mask a problem like this. It is always better to fix something like this if at all possible.