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:
Dec. 21, 1999
Filed:
Jul. 11, 1997
Joe Martin Poss, Rochester, MN (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
A Class IV Partial Response Maximum Likelihood data channel for analog signal processing of a disk drive signal in tracking mode includes a signal error generating circuit for 'folding' the analog disk drive signal around the three PR-IV target values of +1, -1 and 0. Using the smaller error signal rather than the larger analog disk drive signal by which the disk drive signal deviates from the target values results in significant power saving with no reduction in electronic signal to noise ratio. An integrated error generating circuit generates both a gain error signal and a timing error signal from the folded error signal for feedback control of the data channel variable gain amplifier and variable clock oscillator. Shared processing of the timing and gain error signals results in power savings and simpler circuitry.