Color television receivers
US4283739A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Aug 30, 1979 |
| Grant date | Aug 11, 1981 |
| Priority date | — |
| Expiry date | Aug 30, 1999 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N9/642
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
In a color television receiver, especially for NTSC or color television signals, the intermediate frequency is a phase-lock integral multiple of the sub-carrier frequency. Preferably the intermediate frequency is 4N times the sub-carrier frequency, where N is an integer. The receiver may include a crystal controlled oscillator phase locked to a multiple of the color burst frequency, the oscillations from the oscillator compared with the intermediate frequency and the result of the comparison used to control the frequency of a local oscillator. The oscillations from the crystal controlled oscillator may be used directly for synchronous demodulation of the intermediate frequency signal to give a Y or Y-chroma signal and after addition of a signal of sub-carrier frequency and suitable phase adjustment for synchronous demodulation to give U- and V- signals. Alternatively, the crystal oscillator oscillation and a signal of sub-carrier frequency derived from it may be used separately to give the U- and V- signals.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.