64b/66b encoding question

Hi everyone,

If anyone is familiar with this type of encoding, could you please tell me if the 64 bits of data is scrambled first and then encoded, or the other way around?

The reason I ask is because I've seen both ways. PDFs on google in general say that the data is scrambled first, but several reference design by Xilinx (I eventually will need to implement this in an FPGA) show that the scrambling is done at the end before transmission.

Thanks for any clarification,
czhe

Anyone?

Perhaps I didn't post in the right place. Is there a more appropriate place I can ask about something like this?

Thanks.