The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 06, 1994
Filed:
May. 29, 1992
Hitosi Matui, Tokyo, JP;
NEC Corporation, Tokyo, JP;
Abstract
An adaptive equalizer of the present invention equalizes a data symbol sequence containing intersymbol interference and nonlinear distortions extending over several symbols, e.g., a digital signal from the read head of a high density magnetic recording and playback apparatus, thereby producing an equalized output free from such distortions. Presumed value storing means stores a plurality of presumed value signals read out of the combinations of an equalization address signal and a Viterbi transition symbol sequence signal. Error calculating means outputs a plurality of error signals representative of differences between the plurality of presumed value signals and an input data symbol. Viterbi algorithm equalizing means executes equalization according to a Viterbi algorithm and by using the plurality of error signals as branch metrics, thereby producing a presumed symbol associated with the input data symbol, the equalization address signal, and a correction address signal. Correcting means updates the presumed value signal of the presumed value signal storing means designated by the correction address signal with the input data symbol.