18.104.22.168.3. FHT Gray-Coder and Pre-Coder
PAM4 patterns generated in PAM4 mode are gray-encoded by default. For NRZ signals, the gray-coder is bypassed.
The transmitter also includes an optional pre-coder that you can enable for both PAM4 and NRZ signals. Once you turn it on, it performs 1÷(1+D) encoding on all data bits until you disable it.
For the FHT gray-decoder and pre-decoder, reverse the process for the FHT gray-coder and pre-coder.