Muting circuit in a PCM recording and reproducing apparatus
US4309726A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 28, 1980 |
| Grant date | Jan 5, 1982 |
| Priority date | — |
| Expiry date | May 28, 2000 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B20/1813
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Digital data units representative of analog audio signal are constructed into a data unit sequence with an error detection code being added to each of the data units for detecting coding errors within the data unit, and data synchronizing signals are inserted one for every predetermined interval of the data unit sequence to constitute a PCM data sequence, which is recorded and reproduced. The number of times of coding errors detected within the data unit by the error detection code during the time period between one data synchronizing signal and the next following data synchronizing signal is monitored and when the number exceeds a first predetermined count, the audio output is muted, and when the number decreases below a second predetermined count which is much smaller than the first predetermined count, the muting mode of the audio output is released to prevent the noise output.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.