A New Adaptive Technique for Transmitter Pre-Emphasis and Receiver Equalization in a High-Speed Backplane Environment

Abstract

In this paper, a new adaptive equalization technique of a multi-gigabit channel is proposed. This approach calculates the voltages probability density functions of the received signal; and based on the spread of the PDF curves, weights of FIR filters are updated. The algorithm was tested in a Tyco XAUI-FR4 backplane.

A 7.5Gb/s transmitter with self-adaptive FIR

“…Few methods were proposed to adapt transmit FIR filters [1,2,3]. As these methods rely on back-channels or coding overheads to exchange information between far end receiver and transmitter, they are facing some resistance in the industry due to the extra complexity involved.…”

Transmitter Pre-emphasis and Adaptive Receiver Equalization for Duobinary Signaling in Backplane Channels

“…The use of transmitter and receiver equalizers achieves better quality at greater data rate than [2]. Additionally, the error correcting capabilities of duobinary signaling could be exploited.…”

“…To increase data rate to 5 GB/s and higher, equalization and Multi-Level Signaling (MLS) are being researched [1][2][3][4][5][6][7][8][9][10]. In systems with equalization, pre-emphasis, based on FIR filters, is performed to boost high frequency signal content on the transmitter side and decision feedback equalization, along with linear feed-forward equalization, is used to combat reflections at the receiver [2]. The FIR pre-emphasis and receiver filters coefficients are first optimized using the LMS algorithm [11]; then, the updated coefficients are communicated back to the far-end transmitter where they are applied.…”

Characterization of a gigabit transceiver for the ATLAS inner tracker pixel detector readout upgrade

“…The downstream channel takes the 2.56 Gbps data from the VTRx+ as the input source and then pre-emphasizes [15] them to meet the requirements of the Aggregator. The amplitude of these differential signals is from 75 mV to 1V (peak-peak).…”