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:
Jun. 15, 1993
Filed:
May. 21, 1991
Jonathan D Coker, Rochester, MN (US);
Francois B Dolivo, Waedenswil, CH;
Richard L Galbraith, Rochester, MN (US);
Wolfgang H Schott, Rueschlikon, CH;
Pablo A Ziperovich, San Jose, CA (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
A method and apparatus are provided for controlling a digital filter function included in a data path within gain and timing control loops of a PRML magnetic recording channel. The digital filter function is removed from the data path during an acquisition mode and the digital filter function is restored to the data path during a tracking mode. A predetermined gain and a quantized delay at a synchronization frequency are provided when switching from acquisition mode to tracking mode. A unity gain and a delay of an integer number of sample periods are provided at a synchronization frequency when switching from acquisition mode to tracking mode.