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. 11, 2000
Filed:
Jan. 02, 1996
Gordon J Smith, Rochester, MN (US);
Hal Hjalmar Ottesen, Rochester, MN (US);
David William Abraham, Ossining, NY (US);
Anthony Paul Praino, Poughquag, NY (US);
Mark Edward Re, Los Gatos, CA (US);
Hemantha Kumar Wickramasinghe, Chappaqua, NY (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
An apparatus and method for reading an information signal from a magnetic storage medium using a magnetoresistive (MR) head, and separating a thermal signal component and, if present, a magnetic signal component from the information signal. A signal separation/restoration module eliminates distortion in the magnetic signal component of a readback signal induced by a thermal signal component of the readback signal. A finite impulse response (FIR) filter may be employed in the signal separation/restoration module to eliminate the distortion in the magnetic signal. The signal separation/restoration module may be employed to extract the thermal signal component from the readback signal. In one configuration, an MR head is coupled to an arm electronics (AE) module, having a highpass filtering behavior, and a signal separation/restoration module that includes an inverse filter having a transfer function inverse to that of the effective highpass filter of the AE module. The inverse filter may be an infinite impulse response (IIR) filter. In another embodiment, the magnetic and thermal signal components of a readback signal are respectively extracted and processed so as to linearly correspond to head-to-disk spacing. Head-to-disk spacing change using the thermal signal is used to detect disk surface defects, topographic variations, and servo control surface variations.