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. 25, 2003
Filed:
Aug. 23, 2001
Chris Carrington, Gonzales, CA (US);
Peter Cheng-I Fang, San Jose, CA (US);
Don Horne, Raymond, WA (US);
Christopher Dana Keener, San Jose, CA (US);
Kenneth Donald Mackay, San Jose, CA (US);
Antonio Perez, Jr., San Jose, CA (US);
Frederick William Stukey, Jr., San Jose, CA (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
A method and system for the rapid automatic screening of GMR heads for Barkhausen noise during production. This system rapidly and repeatedly measures associated noise in a GMR head subjected to a smoothly-varying external transverse magnetic field. The repeated Transverse Magnetic-field Excited Noise (TMEN) measurements are automatically sorted into bins to form a histogram, which is then automatically evaluated to develop TMEN range and weighted sum measures, which are then compared with predetermined standards for automatic acceptance or rejection of the GMR head under test. The GMR sensor Barkhausen noise is quantified through the use of a bandpass filter to remove all direct sensor responses, leaving only the noise signals, which are then repeatedly sampled to develop valid statistical Barkhausen noise measures suitable for automated analysis.