Apparatus and method for generating a horizontal reset signal synchronous with a subcarrier locked clock
US5053862A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 14, 1989 |
| Grant date | Oct 1, 1991 |
| Priority date | — |
| Expiry date | Apr 14, 2009 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N9/44
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A method and apparatus for synchronizing a received television signal to a subcarrier locked signal is provided. The apparatus includes a comparison block for determining whether the received television signal and subcarrier locked signal are related by a predetermined fixed frequency relationship and for providing indications of the same, and a signal generation block for dividing down the subcarrier locked signal according to the predetermined fixed frequency relationship so as to provide an output signal which is synchronized with the subcarrier locked signal, and at a frequency determined according to the fixed frequency relationship when the signals are related. The apparatus is particularly useful in PIP applications where the received television signal is a horizontal signal and the subcarrier locked signal is a four times multiple of the subcarrier frequency. The comparison block preferably includes a counter and a windowing circuit for determining whether edges of horizontal signal pulses are received within or outside a predetermined time window, and a decision circuit for determining whether the occurrences (counts) of in and out of window edges are indicative of related…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.