Patent ID: 6154870
Filing Date: 2000-11-28
Classification: G11B,H03M

Abstract:
A method for communicating a digital signal in a manner reducing risk of corruption of said signal by noise, said method comprising steps of:(a) encoding an 8-bit byte of digital input signal to provide a 9-bit codeword signal such that: (i) no sequence of 4 consecutive transitions occurs in said 9-bit codeword signal, (ii) said 9-bit codeword signal does not end with a sequence of 2 or more consecutive transitions, (iii) said 9-bit codeword signal does not begin with more than 2 consecutive transitions, and (iv) sequences of 3 consecutive transitions, if any, begin only on a 2nd, 4th, 6th, or 9th bit of said 9-bit codeword signal;(b) serializing said 9-bit codeword signal to generate a serialized subsequence signal;(c) precoding said serialized subsequence signal by subjecting it to a transfer function 1/(1.sym.D) to generate a precoded serialized signal, where D represents a previous bit in a signal subjected to a transfer function;(d) equalizing said precoded serialized signal for a transmission path subject to possible noise corruption, the precoded serialized signal being equalized to provide a coded serialized signal such that, when the coded serialized signal thereafter has been transmitted over the transmission path, the precoded serialized signal will have been subjected to an effective transfer function selected from a group consisting of: (i) an EPR4 channel transfer function of(1-D)(1+D).sup.2 and (ii) an E.sup.2 PR4 channel transfer function of (1-D)(1+D).sup.3 ;(e) communicating said coded serialized signal over said transmission path to produce a possibly corrupted signal;(f) providing said possibly corrupted signal received from said transmisstion path to a Viterbi detector to generated a maximum likelihood estimate signal, said Viterbi detector utilizing a transfer function inverse to the effective transfer function of the equalizing step;(g) subjecting said maximum likelihood estimate signal to a transfer function that is the inverse of 1/(1.sym.D) to generate a most probable estimate signal;(h) deserializing said most probable estimate signal to generate a deserialized estimate signal; and(i) decoding said deserialized estimate signal inversely with respect to the encoding step such that an 8-bit byte of digital output signal is provided which is a most probable estimate of said 8-bit byte of said digital input signal.