Television tuning system with precision substrate switch assembly
US3965427A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 3, 1974 |
| Grant date | Jun 22, 1976 |
| Priority date | — |
| Expiry date | Sep 3, 1994 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03J1/066
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A VHF television tuner system has four tunable circuits each including an abrupt junction varactor diode having a predictable capacitance-tuning voltage characteristic. The VHF frequency spectrum is divided into Lo and Hi bands encompassing television channels 2-6 and 7-13, respectively. A pair of voltage divider networks comprising precisely trimmed resistive material on a ceramic substrate provide tuning voltage terminals corresponding to the VHF television channels. The end terminals of each divider network are coupled to adjustable potentiometers for setting the tuning voltage at each extreme of the voltage divider. A substrate mounted switch accesses the tuning voltage points, supplies bandswitching voltages and provides AFC defeat between channels.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.