Parallel Scrambler

The scrambler uses the g(x) = 1 + x39 + x58 polynomial on the 64-bit transmit data stream (it ignores the sync bits). The scrambler output can be descrambled by a self-synchronizing descrambler using a similar polynomial as specified in IEEE Std. 802.3 Clause 49.

Pseudo-random test mode is for test pattern generation. The transmitter feeds the scrambler a pre-determined input data block of either 64 zeroes or two local fault sequences, depending on the state of the control input tx_tst_data_sel.