Apparatus for recording and reproducing digital signals using a helical scan
US4930031A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 14, 1988 |
| Grant date | May 29, 1990 |
| Priority date | — |
| Expiry date | Nov 14, 2008 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B2220/913
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An apparatus for recording and reproducing digital signals using a helical scan in which a drum of reduced diameter is employed without changing the tape format. Two heads are mounted on a drum at the same height in opposition to each other with a product of the diameter D of the drum and the wrap-around angle of the tape with respect to the rotary drum being constant while the speed of the drum is increased to a speed N times higher than a predetermined speed. One of the heads is mounted higher than the other by a distance of (1-1/N)P to provide a step, and the other head being is mounted at a position an angle behind the position at which the other head directly opposes the one of the heads, which angle is defined by: ##EQU1## where L is the track length in the tape format used when the rotary drum rotates at the predetermined rotational speed, .THETA. is the track angle, P is the track pitch, and C is a constant dependent on the drum diameter D and the wrap-around angle. Methods for performing high speed searches with this apparatus are also disclosed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.