Title :
Mostly analog disk drive read channel with practical depth-of-two fixed delay tree search
Author :
Wei, Derrick C. ; Sun, Daniel Q. ; Abidi, Asad A.
Author_Institution :
Electr. Eng. Dept., Univ. of California, Los Angeles, CA, USA
fDate :
11/1/2002 12:00:00 AM
Abstract :
A new read-channel arrangement for use with d=1 codes equalizes the input to extended partial response IV (EPR4) for clock recovery, and follows this with a new realization of a fixed delay tree search with decision feedback detector with search depth of two. The detector and a discrete-time phase detector for clock recovery share a five-tap finite-impulse response forward equalizer. Clock recovery from EPR4 is fast, while forward and feedback equalizers need no adaptation of tap weights. The read channel, originally developed for a rate-4/5 X{101} code, is extended to the more efficient rate-6/7 maximum-transition-run (MTR) codes. The detector consists of a conventional decision feedback equalizer, assisted by an error-correction circuit to sense and eliminate the major error events, thus performing as well as tree search with depth of two. With MTR code, the read channel outperforms EPR4 with Viterbi detection by 1 dB.
Keywords :
Viterbi detection; decision feedback equalisers; disc drives; partial response channels; phase detectors; runlength codes; synchronisation; tree searching; EPR4 channel; FIR forward equalizer; Viterbi detection; analog disk drive; clock recovery; decision feedback detector; decision feedback equalizer; depth-of-two fixed delay tree search; discrete-time phase detector; error correction circuit; rate-6/7 maximum-transition-run code; read channel; Clocks; Decision feedback equalizers; Delay; Detectors; Disk drives; Hardware; Phase detection; Signal to noise ratio; Timing; Viterbi algorithm;
Journal_Title :
Magnetics, IEEE Transactions on
DOI :
10.1109/TMAG.2002.804798