Recording medium having a pilot signal with an aligned phase angle in adjacent tracks
US4313191A · kind A · utility
35Cited by
4References
4Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Mar 31, 1980 |
| Grant date | Jan 26, 1982 |
| Priority date | — |
| Expiry date | Mar 31, 2000 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B2220/20
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A recording medium, such as a light-reflective video disc, having a plurality of substantially parallel information tracks, each track formed by a succession of spaced, information-bearing indicia having reduced reflectivity. Each track records both a modulated carrier signal and a pilot signal, the pilot signal having a prescribed frequency substantially lower than a substantial portion of the modulated carrier signal. The duty cycle of the spaced indicia forming each track varies in accordance with the phase angle of the recorded pilot signal, and the pilot signal's phase angle is aligned with itself on adjacent tracks.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.