Zero guard-band skip-field video cassette recorder
US4931883A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 18, 1986 |
| Grant date | Jun 5, 1990 |
| Priority date | — |
| Expiry date | Sep 18, 2006 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N5/7826
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A skip-field guard-bandless video tape recorder records and plays back adjacent tracks on a video tape with two closely adjacent heads of opposing head gap azimuth angles (to suppress cross-talk), only during alternate (odd) half-rotations of the head drum. Unavoidable cross-talk of synchronization pulses from adjacent tracks does not create visible interference or timing errors during playback by virtue of a special offset angle .theta..sub.1, between the adjacent recording heads, proportional to the linear offset distance between adjacent tracks. During playback, skipped fields are "filled-in" by a repetition of each recorded field through a second (duplicate) pair of closely adjacent heads of opposing azimuth positioned to retrace the recorded tracks during the other alternate (even) half-rotations of the head drum. An offset angle .theta..sub.2 between the two head pairs (i.e., between opposing heads of like azimuth) corresponds to a half horizontal video line and provides for precise self-interlacing of the repeated fields.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.