Compressed audio silencing
US4825303A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 18, 1987 |
| Grant date | Apr 25, 1989 |
| Priority date | — |
| Expiry date | May 18, 2007 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N7/002
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A method and apparatus for suppressing spurious audio frequency sounds in a system in which electrically represented audio frequency sounds are very significantly raised in frequency and are conformed to a video line signal format. A sufficient number of guard samples ("M") are included at the beginning of each line of electrically represented audio frequency sounds to allow the amplitude response of the video line signal to reach the specified value prior to the occurrence of the samples that are used. The additional guard samples are provided by RAM memory (3), which is controlled by state machine (4). Fewer additional guard samples ("K") may be provided at the end of a video line to enhance tolerance to small timing variations. This method and apparatus allows satisfactory functioning with apparatus having a limited range of frequency response and without precise timing adjustment of video information signals in relationship to the line of synchronizing signal, thus being less costly to manufacture and use.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.