Circuit for digitally encoding an analog television signal
US4075656A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jan 26, 1977 |
| Grant date | Feb 21, 1978 |
| Priority date | — |
| Expiry date | Jan 26, 1997 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N11/04
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A circuit for digitally encoding an analog television signal by sampling is provided. The circuit includes an analog-to-digital encoder which receives both the analog television signal and a sampling signal generated by the circuit. A clock signal generator is utilized providing a signal of a frequency equal to a first integral multiple of a desired sampling signal frequency and to a second integral multiple of the frequency of a synchronizing component of the television signal. The clock signal is phase-locked to that synchronizing component. A frequency divider is utilized to divide the frequency of the clock signal to provide a sampling signal of a desired frequency. The resulting sampling signal frequency is a non-integral rational multiple of the horizontal sync frequency. The frequency divider is set during each horizontal blanking period to a predetermined state to provide a sampling signal whose phase is the same at the beginning of each horizontal line of the analog television signal. Vertical alignment of sampling signals on subsequent horizontal lines of the television signal results.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.