Media flaw detection apparatus for a magnetic disk drive with squaring and summing of in-phase and quadrature-phase detected signals
US5121057A · kind A · utility
12Cited by
10References
21Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Dec 21, 1990 |
| Grant date | Jun 9, 1992 |
| Priority date | — |
| Expiry date | Dec 21, 2010 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03D1/2245
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A media flaw detection apparatus having a sensitivity which is independent of the location of the flaw relative to the written test signal. The apparatus is equally sensitive to missing or extra bit defects. According to the invention, in-phase and quadrature-phase signals are heterodyned against the analog playback input signal. The resulting signals are squared and summed to produce a signal analogous to the effect of the flaw.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.