Sound recording on color film by hue modulation
US3969593A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 8, 1974 |
| Grant date | Jul 13, 1976 |
| Priority date | — |
| Expiry date | Nov 8, 1994 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B7/0032
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Sound is recorded on color motion picture film in the form of variations of ue rather than overall density, with inverse density variations of different color media of the film directly superposed. With three distinct color media it is possible in that manner to record two separate sound channels, the respective channels being hue modulated on distinct hue axes. Such hue modulated sound records are inherently virtually free from noise due to occlusions such as dirt and scratches on the film. Apparatus is disclosed for recording sound in the described manner and for reproducing sound from such records, including electronic means for reducing additional forms of noise. The inherent reduction of noise permits the normal sound track area of conventional films to accommodate several distinct tracks, each of which can carry two distinct sound channels or one sound channel and a control channel. Particularly effective and economical apparatus is described which can replace part of a conventional sound reproducing head and provide an existing motion picture projector with capability for reproducing such multi-track records.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.