Center channel derivation for stereophonic cinema sound
US4024344A · kind A · utility
99Cited by
3References
17Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Nov 12, 1975 |
| Grant date | May 17, 1977 |
| Priority date | — |
| Expiry date | Nov 12, 1995 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04S2400/05
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
In a stereophonic reproduction system, especially for a cinema, a center channel signal is derived by combining left and right channel signals. In order to harden the center image, particularly in speech, the left and right channel signals are compared and, when they include significant amounts of correlated information, the relative gain of the center channel is enhanced by boosting the gain of that channel and/or cutting the gain of the left and right channels. The test for correlation of information is preferably restricted to speech frequencies and the enhancement of relative gain may be performed only at middle frequencies.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.