Self compensating high density data recording and detection scheme
US4987500A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 14, 1988 |
| Grant date | Jan 22, 1991 |
| Priority date | — |
| Expiry date | Nov 14, 2008 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B20/1419
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
The present invention utilizes a dual frequency data writing scheme. At a first frequency, flux transitions are achieved which result in large excursions of the information signal. In the preferred embodiment, the first frequency approximates the maximum frequency at which such excursions can occur. A second higher frequency is utilized to create the very small or no excursions. At this second higher frequency, a complex flux transition is not achieved. Therefore, there is little or no information signal. Information is represented by the presence or absence of excursions. In the preferred embodiment, the first frequency is approximately 33,000 flux changes per inch, and the second frequency is approximately 67,000 flux changes per inch. In order to detect data written by the present scheme, an adaptive, self-compensating scheme is utilized. The present invention utilizes an excursion detection scheme which is pattern and radii independent. This scheme is self-adjusting in real time and provides recovery of the nominal flux transition independent of the information pattern. Data recovery is qualified through use of a novel excursion detection scheme. This scheme compares variations…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.