Multilevel record modulator and demodulator
AssigneeMatsushita Electric Industrial Co., Ltd.
InventorsHiroki Mouri, Takashi Yamamoto, Hiroyuki Nakahira, Akira Yamamoto
Life of this patent
Estimating the term…
Abstract
An encoding efficiency higher than 1 is achieved by accomplishing ternary recording on a recording medium. For this purpose, an 8-bit binary data word is converted to a 5-symbol ternary code word. A look-up table stores a modulation/demodulation table defining the correspondence between the binary data word (8B) and the ternary code word (5T). A table generating circuit generates the modulation/demodulation table to be stored in the look-up table such that each of constraints specified by a plurality of parameters is satisfied. If a PRML (Partial Response Maximum Likelihood) scheme is combined with an 8B5T code thus obtained, a signal-to-noise ratio is improved.
Claims11
A multilevel record modulator and demodulator having a function of converting a p-bit (p is an integer) binary data word to a q-symbol (q is an integer) multilevel code word such that multilevel recording on a recording medium is accomplished, the modulator and demodulator comprising:
- a look-up table for storing a modulation/demodulation table defining a correspondence between the binary data word and the multilevel code word;
- and
- a table generating circuit for receiving a plurality of parameters and generating the modulation/demodulation table to be stored in the look-up table such that each of constraints specified by the plurality of parameters is satisfied.
Dependencies are inferred from the claim text.