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:
Nov. 22, 1994
Filed:
Aug. 03, 1992
Hitachi, Ltd., Tokyo, JP;
Abstract
A magnetic recording and reproducing apparatus, comprising a magnetic recording medium, a head arrangement for reading data from or writing data on the magnetic recording medium including an inductive recording head and a magnetoresistive reproducing head, and a phase discriminating circuit for discriminating data `1` from peaks of a waveform reproduced by the head. The phase discriminating circuit has a differential circuit for differentiating the waveform, a pulse circuit for producing a zero cross pulse from a zero-level crossing point of the differentiated waveform, a discriminating circuit for discriminating `1` and `0` of the data with use of pulses output from the pulse circuit and a discriminating window needed for judgment of `1` and `0` of the data, and a decoding circuit for decoding and feeding out the data output of the discriminating circuit. The head comprises a recording head of inductive type, and a reproducing head of magnetoresistive type. The phase discriminating circuit comprises a circuit for controlling a magnetic bias level for the magnetoresistive reproducing head so that a change of resistance of the magnetoresistive reproducing head due to magnetic field is made virtually equal both at positive and negative polarity waveform peaks.