Abrupt junction varactor diode television tuner

Abstract From the Canadian patent

A VHF television tuner 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 …