Remote-control tuning system

Claim 1

A remote-control tuning system comprising a series-connected circuit consisting of a plurality of oscillators for generating signals of different frequencies; a first matrix circuit to which the outputs of said oscillators are applied and which combines said outputs according to a program preset by a means operated to selected a desired channel; and a speaker for converting the output of said first matrix circuit into an ultrasonic wave and radiating said ultrasonic wave into the atmosphere; a microphone for receiving said ultrasonic wave and converting said ultrasonic wave to an electric signal; a converter in which said electric signal is decomposed into a plurality of signals of different frequencies by means of a plurality of filters covering different filter bands, said decomposed signals being converted into binary output voltages; a second matrix circuit for receiving said binary output voltages and converting said voltages into a plurality of corresponding binary code signals at a plurality of output terminals; a switching element circuit comprising a first plurality of variable series-connected resistors; a first fixed resistor; a first plurality of silicon-controlled rectifiers coupled between said first fixed resistor and corresponding junctions of said first plurality of series-connected variable resistors, application of a binary code signal from said second matrix circuit to a selected one of said first plurality of siliconcontrolled rectifiers turning said selected rectifier on to couple a predetermined number of said variable resistors in series with said fixed resistor and a voltage source, the voltage across said first fixed resistor being coupled to a varactor diode in a VHF tuner section; a second plurality of variable resistors having a common terminal coupled to said voltage source; a second fixed resistor; a second plurality of silicon-controlled rectifiers coupled between said second fixed resistor and taps on corresponding ones of said second plurality of variable resistors, application of a binary code signal to one of said second plurality of silicon-controlled rectifiers coupling a predetermined one Of said second plurality of variable resistors to said second fixed resistor and said voltage source, the voltage across said second fixed resistor being coupled to a varactor diode in a UHF tuner section; and means coupling binary code signals from predetermined output terminals of said second matrix circuit to the siliconcontrolled rectifiers in said switching element circuit, said means switching said silicon-controlled rectifiers on or off in accordance with the signal at said predetermined output terminals.