Logic for matrix systems for reproducing quadraphonic sound
US3967063A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 3, 1975 |
| Grant date | Jun 29, 1976 |
| Priority date | — |
| Expiry date | Mar 3, 1995 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04S3/006
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Apparatus for decoding four separate channels of information transmitted on two channels or transduced from a medium having only two separate tracks and presenting it on four loudspeakers to give the listener the illusion of sound coming from a corresponding number of separate sources. The realism is enhanced by a decoding matrix which accepts the two outputs from the medium, which may be a stereophonic disc record, separates them into four independent channels each respectively carrying predominantly the information contained in one of the four original recorded sound signals, and, utilizing a logic network which senses the signal amplitudes and phase positions, derives control signals for controlling the gains of amplifiers associated with the four loudspeakers. The logic control circuitry improves the realism of four independent channels by essentially eliminating undesired cross-talk which may accompany the signals produced by the decoding matrix.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.