Frequency determining apparatus
US4561021A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 22, 1983 |
| Grant date | Dec 24, 1985 |
| Priority date | — |
| Expiry date | Mar 22, 2003 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R23/005
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A frequency determining apparatus discriminates between two different frame frequencies in television signals. A binary counter (4) makes a 1/64 frequency division of a horizontal synchronizing signal outputted from a horizontal synchronizing signal producing circuit (2), and further makes a 1/2 frequency division of the frequency divided output therefrom. A NAND gate (5) is responsive to the 1/64 frequency divided output and the 1/2 frequency divided output from the binary counter to detect the normal frame signal at 60 Hz, thereby to set a D-type flip-flop (8). Another NAND gate (51) is responsive to the signal obtained by inverting the 1/64 frequency divided output from the binary counter (4) and the 1/2 frequency divided signal to detect the normal frame signal at 50 Hz, thereby to set another D-type flip-flop (81). An R-S flip-flop (13) is set by the respective outputs from these D-type flip-flops whereby a desired determined signal is outputted.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.