Patent · US Expired

Stereophonic motion picture photographic sound-tracks compatible with different sound projection formats and record and playback apparatus therefore

US4577305A · kind A · utility

12Cited by
3References
21Claims
0Family size

Assignee

Inventors

Key dates

Filing dateMar 14, 1983
Grant dateMar 18, 1986
Priority date
Expiry dateMar 14, 2003

Classification

  • Technology area (CPC H)Electricity
  • CPC primaryH04S3/02
  • WIPO fieldAudio-visual technology
  • WIPO sectorElectrical engineering

Abstract

Discrete four-channel photographic (optical) motion picture sound-tracks are disclosed that are compatible with existing monophonic and stereo variable area (SVA) theatre projection equipment. Six track and four track embodiments are disclosed. In the four track embodiments 4-4-4 matrix encoding is employed in producing the sound-track. Apparatus for recording and reproducing the compatible four-channel sound-tracks are also disclosed.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.