LMS filter adaptation in PRML channels

摘要

Current state-of-the-art PRML (partial-response, maximum-likelihood) read channels detect user data accurately under very adverse signal conditions. PRML channels are used throughout the hard disk drive (HDD) industry and are rapidly expanding to tape drives, optical drives, and even to Gbit Ethernet. An enabling technology at the core of the PRML channel is the Viterbi detector. This uses a sophisticated algorithm to determine the user's stored data pattern, based on a sequence of samples from the readback waveform. However, there is an equally important signal processing chain that the samples must go through before being presented to the detector.