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:
Jul. 23, 2002
Filed:
Mar. 31, 1999
Robert Allen Hutchins, Tuscon, AZ (US);
Sushama Mahesh Paranjape, Tuscon, AZ (US);
Gene Ho Sonu, San Jose, CA (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
A maximum likelihood detector and a method for maximum likelihood detection of digital samples of channel output of data recorded as analog signals representing a finite number of states. The method comprises, first, providing at least two numerical metric coefficients. The coefficients are derived from the difference between metrics directly associating “0” and “1” states of the recorded signal. The coefficients are respectively applied to each sequential digital sample to generate alternative metrics, and each respective alternative metric is compared to a previous difference metric based on a previous digital sample. Based on the comparison, one of a plurality of provided metrics is selected which minimizes the mean squared error with respect to the previous metric. Then, the one of the finite number of states represented by the selected metric is identified, and a maximum likelihood path memory is set to a maximum likelihood state dictated by the identified one of the finite states, thereby detecting the recorded analog signals. The numerical coefficients may be programmed based on different removable media and the probability that the samples comprise a data sequence.