目前调试10AS066高速收发器，FPGA连接光模块，光模块收发回环，现在测试发现低于7Gbps数据收发正常，但是高于7Gbps就不稳定，到9Gbps完全收不到数据，请问这种情况有可能是什么问题呢，有什么办法可以排查呢？硬件电路是参考开发板做的，电路设计应该没有问题。

Hi,

Sorry for the delay. As I understand it, you are observing the loopback test with optical module seems unable to receive data correct at data rate >7Gbps. Lower than 7Gbps, there is no issue. This seems to be trending to signal integrity issue. To further narrow down, just wonder if you have had a chance to test enabling internal serial loopback and test at data rate >7Gbps to see if data can be received correctly. This would be helpful to narrow down to signal integrity issue.

Thank you.