Partial Response and Noise Predictive Maximum Likelihood (PRML/NPML) Equalization and Detection for High Speed Serial Link Systems

摘要

In this paper, we explore advanced equalization and detection methods for lossy channels and a noisy environment for high speed serial link systems. The use of digital signal processing (DSP) with multi-level encoding allows the consideration of advanced DSP equalization and detection techniques. Partial response maximum likelihood (PRML) equalization and detection is explored as a potential advanced solution to address these challenges within the context of a DSP based receiver architecture. We examine the efficacy of PRML for non-return to zero (NRZ) two level modulation (PAM2) and 4 level (PAM4) modulation and relate the performance to present day state of the art equalization and detection architectures employed in serial links. We also examine the performance with noise predictive maximum likelihood (NPML) detection which can be considered a generalized PRML architecture. Performance analysis and comparisons are made both prior to forward error correction (FEC) coding and after the use of FEC coding.