Patent GB-1368975-A (GB)
Title: Remote-control tuning system
IPC: H04N5/44
Filed: 1971-11-26
Abstract: 1368975 Remote controlled tuning; SCR gating circuits MATSUSHITA ELECTRIC INDUSTRIAL CO Ltd 26 Nov 1971 [28 Nov 1970] 55124/71 Headings H3Q and H3T [Also in Division G4] In a remote control tuning system having a first matrix circuit M, Fig. 3, which combines the outputs of different frequency oscillators OSC1-OSC4 according to a program preset by means P operated to a desired channel, a speaker 2P converts the output from the first matrix circuit M into an ultrasonic wave which is received by a microphone MIC Fig. 4, a converter including a plurality of filters F1 F2, F3, F4 provides a plurality of signals of different frequency f1-f4 from the electric output signal from the microphone and these signals f1-f4 are converted into binary output voltage QAQD and are fed to a second matrix circuit (12, Figs. 2 and 5, not shown) for providing a plurality of binary coded output signals. Application of a binary coded signal from the second matrix circuit to a selected one of a first plurality of silicon controlled rectifiers CR13- CR24, Fig. 9, couples a predetermined number of a first plurality of variable resistors in series with a first fixed resistor, the voltage BTV across which is coupled to a varactor diode in a VHF tuner section, and application of a binary coded signal from the second matrix to a selected one of a second plurality of silicon controlled rectifiers CR10-CR12 couples a predetermined one of a second plurality of variable resistors to a second fixed resistor, the voltage BTU across which is coupled to a varactor diode in a UHF tuner section. A remote control transmitter, Fig. 3, has a control panel P provided with buttons for determining the combinations of frequencies from oscillators OSC1-OSC4 as selected by the matrix circuit M. A receiver, Fig. 4, separates the frequencies received in filters F1-F4 and provides via bi-stables FF1-FF4 and a diode matrix (12, Figs. 2 and 5, not shown) binary signals for control of the switching circuits of Figs. 6 and 9. To select a VHF channel button V is operated followed by operation of the required channel button. The binary control signal corresponding to V received switches on SCR CR8 which due to the capacitors C1-C6 and connection G turns off the other SCR's. A delayed output from a monostable MM-2 then turns on CR4 and CR6 to connect the VHF power supply BV and the VHF AGC voltage VAGC. The binary control signal corresponding to the required VHF channel turns on CR1 or CR2 to provide the required voltage BS for switching between high and low frequency channels. A delayed output from a monostable MM-1 then turns CR9 on so as to charge C1- C6. Also the selected output on lines I-XI turns on the required SCR CR13-CR24 to provide the VHF tuning voltage BTV for a T.V. receiver. To select a UHF channel button U is operated followed by operation of the required channel button. This provides binary signals to the inputs of Figs. 6 and 9 which operate similarly to above so as to connect the UHF power supply BU and the UHF AGC voltage UAGC. The UHF tuning voltage BTU is selected by preset variable resistors and the SOR CR10-CR12 which has been turned on.