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. 01, 1998
Filed:
Jun. 05, 1997
David Anthony Freitas, Morgan Hill, CA (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
Track information decoding circuitry of a data storage device servo control system decodes binary track information in a readback servo signal by detecting opposite polarity track information pulse pairs so as to produce a track information signal 'one' bit if the presence of an opposite polarity pulse pair is detected and produce a track information signal 'zero' bit in the absence of an opposite polarity pulse pair, wherein a one bit is produced only if there has been detected a second pulse of a readback signal pulse pair having a magnitude greater than a predetermined threshold value and having a correct polarity. The polarity of the last di-bit of the servo signal AGC field can be used to set the polarity in the pulse qualification process. Alternatively, a pulse detecting circuit at disk start-up decodes the readback signal first assuming a positive leading di-bit pulse and then assuming a negative leading di-bit pulse, determines the number of errors associated with each assumption, and selects the di-bit pulse polarity for further decoding that produced the decoded information having fewer errors.