Method of automatically measuring the horizontal scan frequency of a composite synchronism signal, and an electronic circuit operating in accordance with the method
US5134481A · kind A · utility
10Cited by
9References
9Claims
0Family size
Assignee
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Key dates
| Filing date | Dec 21, 1990 |
| Grant date | Jul 28, 1992 |
| Priority date | — |
| Expiry date | Dec 21, 2010 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N5/46
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A method of automatically measuring the horizontal scan frequency of a composite synchronism signal, comprising horizontal synchronization impulses at line frequency, consists of first performing a count of a number of impulses having a repeat frequency higher than said line frequency, as intervening between two successive impulses at line frequency. The count value, corresponding to said number of impulses, is stored to obtain the line frequency of the signal, and thereafter, a series of down counts is effected, as initiated at predetermined times, until a change of frequency of the signal is detected.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.