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:
Mar. 24, 1998
Filed:
Nov. 08, 1996
Hiroshi Muto, Kawasaki, JP;
Fujitsu Limited, Kawasaki, JP;
Abstract
In a magnetic disk drive in which an analog signal having symmetrical positive and negative odd levels with respect to a zero-level is read out of a magnetic disk by a head, the read analog signal is processed by an AGC circuit and a low pass filter, the processed analog signal is converted into a digital signal by an A/D converter, and the digital signal is demodulated by a demodulator, a zero-level setting circuit for the A/D converter is comprised of: a reference voltage generator for the A/D converter; a zero-level error detector between the read signal and the reference voltage; an accumulator for accumulating the zero-level error from the zero-level error detector; and an equalizer for equalizing the zero-level of the A/D converter to the reference voltage in accordance to an output signal from the zero-level error accumulator. As a result, the conversion accuracy of the A/D converter is improved while employing a small number of bits.