Television captioning system
US4310854A · kind A · utility
135Cited by
6References
16Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Aug 24, 1979 |
| Grant date | Jan 12, 1982 |
| Priority date | — |
| Expiry date | Aug 24, 1999 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N7/0885
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Captioning of television presentations is achieved by transmitting digital data superimposed on the normal FM sound signal by modulation of an ultrasonic subcarrier and receiving the digital data at a viewer's television receiver by picking up the ultrasonic signal from the television receiver's loudspeaker; the received digital data being demodulated and applied to the television receiver as readable alphanumeric captions.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.