An Almost Symmetric (0,3/6) PRML Code
Original Publication Date: 1989-Oct-01
Included in the Prior Art Database: 2005-Jan-29
Partial-response signaling with maximum-likelihood sequence estimation (which we denote by PRML) is a technique, using amplitude detection, which has been investigated for high density magnetic recording of digital data. The technique combines partial-response class IV signaling with maximum likelihood detection in the form of a Viterbi (Image Omitted) decoder. There is a need for constrained codes in this context: to improve timing and gain control, as well as to limit the path memory of the Viterbi decoder. In the presence of an inverse-channel precoder, the input sequences are the same as the output constrained sequences, and hence the simple run-length constraints at the output directly transfer to the input sequences.