Encoding and compensation schemes using improved pre-equalization for the 64B/66B Encoder

This paper proposes an improved pre-equalization approach for the transmitter in the new high speed communication IEEE 802.3ba 40G/100G Ethernet standards. It is noted that the new 64b/66b encoder, for the above standards, causes a shift in the signal´s power spectral density. Preliminary results show that the power shift is not uniform. Depending of the bit rate, in some cases the encoder shifts the spectrum from the low frequency to the high frequency region of the spectrum; at other bit rates is the opposite. This problem is compounded by the attenuation of the signal caused by the frequency response of a typical physical channel. In this paper, a transmitter pre-equalizer is proposed that compensates for this spectrum shift. In addition, this approach is aimed at emerging high speed data standards which are transmitting at 25 Giga bits per second (Gbps) on a single trace using the 64b/66b encoder. Based on our previous experience, a receiver equalizer will be proposed to enhance the performance legacy backplanes so that they can work up to the 25 Gbps speeds.