Screening test for transverse magnetic-field excited noise in giant magnetoresistive heads
US6538430B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 23, 2001 |
| Grant date | Mar 25, 2003 |
| Priority date | — |
| Expiry date | Aug 23, 2021 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T29/49036
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.