Dual-standard SECAM/PAL color TV receiver with automatic control of operating mode
US4438451A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 25, 1982 |
| Grant date | Mar 20, 1984 |
| Priority date | — |
| Expiry date | Feb 25, 2002 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N9/642
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Dual-standard (PAL/SECAM) color TV receiver includes circuitry for automatically controlling the receiver's operating mode in accordance with recognition of the SECAM or format of the received signals. A first sample-and-hold circuit monitors the output of an FM detector responsive to the received signals during blanking "backporch" portions of alternate line intervals, while a second sample-and-hold circuit monitors the output of said FM detector during blanking "backporch" portions of the intervening line intervals. Comparison of the outputs of the two sample-and-hold circuits achieves the desired format recognition. To avoid false recognition, sampling interval beginning is delayed relative to beginning of SECAM lead-in oscillations or swinging bursts, while sampling interval termination substantially coincides with end of blanking interval.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.