Electronic system for automatically tuning to a selected television channel
US4020419A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 5, 1974 |
| Grant date | Apr 26, 1977 |
| Priority date | — |
| Expiry date | Jun 5, 1994 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03J5/0245
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
An all electronic tuning system is described for establishing a frequency of a local oscillator in a television receiver. When a channel selection is made, a number representing the desired channel is entered in a memory circuit. A first plurality of frequencies is generated in response to a channel selection, and a VCO employed as a local oscillator is caused to increase in frequency. When the VCO frequency differs from the first plurality of frequencies by a predetermined amount, a second plurality of frequencies is generated. Each frequency generated in said second plurality of frequencies is compared with said VCO frequency. When a predetermined difference exists between said VCO frequency and said second plurality of frequencies, a count is recorded. When the recorded count is equivalent to the number obtained in the memory circuit, the VCO tuning is inhibited and the VCO frequency is stabilized until a subsequent channel selection is made.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.