Channel selector employing variable capacitance elements for tuning

Claim 2

A television receiver channel selector for selecting one from among a plurality of channel tuning frequencies, comprising: a tuning circuit tunable to said plurality of channel tuning frequencies, including variable capacitance diodes as tuning elements; a plurality of voltage supply circuits for supplying at outputs thereof tuning voltages corresponding to said plurality of channel tuning frequencies; binary memory circuit means having a plurality of outputs for producing binary coded information signals corresponding to said channel tuning frequencies, said memory circuit comprising a binary counter circuit having a plurality of complementary pairs of output terminals; binary decoder means having a plurality of complementary pairs of input terminals connected to said counter circuit output terminals and a further plurality of terminals coupled to the outputs of said voltage supply circuits; means for selectively connecting the outputs of said voltage supply circuits to said variable capacitance diodes for tuning said tuning circuit to one of said channel tuning frequencies, including means selectively connecting the output of one of said voltage supply circuits to said variable capacitance diodes to tune said tuning circuit to the corresponding channel tuning frequency and disconnecting the outputs of all others of said voltage supply circuits from said variable capacitance diodes, the selective connection of said one voltage supply circuit and disconnection of said all other voltage supply circuits being controlled by a given binary decoder means output; a pulse generator circuit coupled to an input of said binary counter circuit for supplying pulses in sequence to said counter circuit and switch means for controlling the supply of pulses from said pulse generator to said counter circuit; and reversing switch means interposed between each set of corresponding pairs of said input and output terminals of said decoder and counter circuit, respectively, for reversing the connections between said input and output terminals within each set of said corresponding pairs of terminals.

Claim 3

A television receiver channel selector for selecting one from among a plurality of channel tuning frequencies, comprising: a tuning circuit tunable to said plurality of channel tuning frequencies, including variable capacitance diodes as tuning elements; a plurality of preset voltage supply circuits, including preset impedances, for supplying at outputs thereof tuning voltages corresponding to said plurality of channel tuning frequencies; binary memory circuit means having a plurality of outputs for producing binary coded information signals indicating pure binary numbers and corresponding to said channel tuning frequencies; binary decoder means having a first plurality of terminals coupled to the corresponding outputs of said binary memory circuit means and a second plurality of terminals coupled to the outputs of said voltage supply circuits; means for selectively connecting the outputs of said voltage supply circuits to said variable capacitance diodes for tuning said tuning circuit to one of said channel tuning frequencies, including means for selectively connecting the output of one of said voltage supply circuits to said variable capacitance diodes to tune said tuning circuit to the corresponding channel tuning frequency and disconnecting the outputs of all others of said voltage supply circuits from said variable capacitance diodes, the selective connection of one said voltage supply circuit and disconnection of said all other voltage supply circuits being controlled by a signal appearing on a given one of said second plurality of decoder means terminals; a plurality of switching elements having control terminals respectively connected to said second plurality of terminals of said binary decoder means, the corresponding one of said switching elements being urged conductive by said signal appearing at said given one of said second plurality of decoder terminals; and a plurality of indicating means connected in series with the respective switching elements.

Claim 4

A television receiver channel selector for selecting one from among a plurality of channel tuning frequencies, comprising: a tuning circuit tunable to said plurality of channel tuning frequencies, including variable capacitance diodes as tuning elements; a plurality of preset voltage supply circuits, including preset impedances, for supplying at outputs thereof tuning voltages corresponding to said plurality of channel tuning frequencies; binary memory circuit means having a plurality of outputs for producing binary coded information signals indicating pure binary numbers and corresponding to said channel tuning frequencies; binary decoder means having a first plurality of terminals coupled to the corresponding outputs of said binary memory circuit means and a second plurality of terminals coupled to the outputs of said voltage supply circuits; means for selectively connecting the outputs of said voltage supply circuits to said variable capacitance diodes for tuning said tuning circuit to one of said channel tuning frequencies, including means for selectively connecting the output of one of said voltage supply circuits to said variable capacitance diodes to tune said tuning circuit to the corresponding channel tuning frequency and disconnecting the outputs of all others of said voltage supply circuits from said variable capacitance diodes, the selective connection of one said voltage supply circuit and disconnection of said all other voltage supply circuits being controlled by a signal appearing on a given one of said second plurality of decoder means terminals; a plurality of switching elements having control terminals respectively connected to said second plurality of terminals of said binary decoder means, the corresponding one of said switching elements being urged conductive by said signal appearing at said given one of said second plurality of decoder terminals; and a plurality of indicating means connected in series with the respective switching elements.

Claim 5

A television receiver channel selector for selecting one from among a plurality of channel tuning frequencies, comprising: a tuning circuit tunable to said plurality of channel tuning frequencies, including variable capacitance diodes as tuning elements; a plurality of voltage supply circuits for supplying at outputs thereof tuning voltages corresponding to said plurality of channel tuning frequencies; binary memory circuit means having a plurality of outputs for producing binary coded information signals corresponding to said channel tuning frequencies, said binary memory circuit means comprising a binary counter including N flip-flop circuits for generating a first set of binary coded information signals corresponding to said channel tuning frequencies; binary decoder means having a first plurality of terminals coupled to the corresponding outputs of said binary memory circuit means and a second plurality of terminals coupled to the outputs of said voltage supply circuits; means for selectively connecting the outputs of said voltage supply circuits to said variable capacitance diodes for tuning said tuning circuit to one of said channel tuning frequencies, including means selectively connecting the output of one of said voltage supply circuits to said variable capacitance diodes to tune said tuning circuit to the corresponding channel tuning frequency and disconnecting the outputs of all others of said voltage supply circuits from said variable capacitance diodes, the selective connection of said one voltage supply circuit and disconnection of said all other voltage supply circuits being controlled by a signal appearing on a given one of said second plurality of decoder means terminals; channel selecting means for generating a second set of binary coded information signals corresponding to desired channels to be tuned; indicating means for sequentially indicating a tuned channel, including drive means for sequentially stepping said indicating means; pulse generating means coupled to said indicating means for generating a pulse each time said indicating means is stepped by said drive means, the output of said pulse generating means being coupled to the input of said binary counter to step said counter each time a pulse is produced by said pulse generating means; means for comparing said first and second sets of binary coded information signals and producing an output signal upon the detection by said comparing means of coincidence between said first and second sets of signals; and switching means connected between said comparing means and said indicator drive means for permitting said drive means to step said indicating means by the output signal of said comparing means when said first set of signals do not coincide with said second set of signals, and said switching means being cut off by the output signal of said comprising means for shutting off said drive means when said first set of signals coincide with said second set of signals.

Claim 6

A television receiver channel selector for selecting one from among a plurality of channel tuning frequencies, comprising: a tuning circuit tunable to said plurality of channel tuning frequencies, including variable capacitance diodes as tuning elements; a plurality of voltage supply circuits for supplying at outputs thereof tuning voltages corresponding to said plurality of channel tuning frequencies; binary memory circuit means having a plurality of outputs for producing binary coded information signals corresponding to said channel tuning frequencies, said binary memory circuit means comprising a binary counter including N flip-flop circuits for generating a first set of binary coded information signals corresponding to said channel tuning frequencies; binary decoder means having a first plurality of terminals coupled to the corresponding outputs of said binary memory circuit means and a second plurality of terminals coupled to the outputs of said voltage supply circuits; means for selectively connecting the outputs of said voltage supply circuits to said variable capacitance diodes for tuning said tuning circuit to one of said channel tuning frequencies, including means selectively connecting the output of one of said voltage supply circuits to said variable capacitance diodes to tune said tuning circuit to the corresponding channel tuning frequency and disconnecting the outputs of all others of said voltage supply circuits from said variable capacitance diodes, the selective connection of said one voltage supply circuit and disconnection of said all other voltage supply circuits being controlled by a signal appearing on a given one of said second plurality of decoder means terminals; channel selecting means for generating a second set of binary coded information signals corresponding to desired channels to be tuned; indicating means for sequentially indicating a tuned channel, including drive means for sequentially stepping said indicating means; pulse generating means coupled to said indicating means for generating a pulse each time said indicating means is stepped by said drive means, the output of said pulse generating means being coupled to the input of said binary counter to step said counter each time a pulse is produced by said pulse generating means; means for comparing said first and second sets of binary coded information signals and producing an output signal upon the detection by said comparing means of coincidence between said first and second sets of signals; and switching means connected between said comparing means and said indicator drive means for permitting said drive means to step said indicating means by the output signal of said comparing means when said first set of signals do not coincide with said second set of signals, and said switching means being cut off by the output signal of said comprising means for shutting off said drive means when said first set of signals coincide with said second set of signals.

Claim 7

A television receiver channel selector for selecting one from among a plurality of channel tuning frequencies, comprising: a tuning circuit tunable to said plurality of channel tuning frequencies, including variable capacitance diodes as tuning elements; a plurality of voltage supply circuits for supplying at outputs thereof tuning voltages corresponding to said plurality of channel tuning frequencies; binary memory circuit means having a plurality of outputs for producing binary coded information signals corresponding to said channel tuning frequencies, said memory circuit comprising a binary counter circuit having a plurality of flip-flop circuits each having an input terminal and a pair of output terminals; binary decoder means having a plurality of complementary pairs of input terminals connected to respective pairs of said flip-flop circuit output terminals and a further plurality of terminals coupled to the outputs of said voltage supply circuits; means for selectively connecting the outputs of said voltage supply circuits to said variable capacitance diodes for tuning said tuning circuit to one of said channel tuning frequencies, including means selectively connecting the output of one of said voltage supply circuits to said variable capacitance diodes to tune said tuning circuit to the corresponding channel tuning frequency and disconnecting the outputs of all others of said voltage supply circuits from said variable capacitance diodes, the selective connection of said one voltage supply circuit and disconnection of said all other voltage supply circuits being controlled by a given binary decoder means output; a pulse generator circuit coupled to an input of said binary counter circuit for supplying pulses in sequence to said counter circuit and switch means for controlling the supply of pulses from said pulse generator to said counter circuit; and means for connecting said flip-flop circuits in a sequential connection, including switching means for connecting the pair of output terminals of any one of said flip-flop circuits to the input terminal of the subsequent flip-flop circuit, wherein the pulses of said pulse generator circuit are applied to the first flip-flop circuit of said sequential connection.

Claim 8

A television receiver channel selector for selecting one from among a plurality of channel tuning frequencies, comprising: a tuning circuit tunable to said plurality of channel tuning frequencies, including variable capacitance diodes as tuning elements; a plurality of voltage supply circuits for supplying at outputs thereof tuning voltages corresponding to said plurality of channel tuning frequencies; binary memory circuit means having a plurality of outputs for producing binary coded information signals corresponding to said channel tuning frequencies, said memory circuit comprising a binary counter circuit having a plurality of flip-flop circuits each having an input terminal and a pair of output terminals; binary decoder means having a plurality of complementary pairs of input terminals connected to respective pairs of said flip-flop circuit output terminals and a further plurality of terminals coupled to the outputs of said voltage supply circuits; means for selectively connecting the outputs of said voltage supply circuits to said variable capacitance diodes for tuning said tuning circuit to one of said channel tuning frequencies, including means selectively connecting the output of one of said voltage supply circuits to said variable capacitance diodes to tune said tuning circuit to the corresponding channel tuning frequency and disconnecting the outputs of all others of said voltage supply circuits from said variable capacitance diodes, the selective connection of said one voltage supply circuit and disconnection of said all other voltage supply circuits being controlled by a given binary decoder means output; a pulse generator circuit coupled to an input of said binary counter circuit for supplying pulses in sequence to said counter circuit and switch means for controlling the supply of pulses from said pulse generator to said counter circuit; and means for connecting said flip-flop circuits in a sequential connection, including switching means for connecting the pair of output terminals of any one of said flip-flop circuits to the input terminal of the subsequent flip-flop circuit, wherein the pulses of said pulse generator circuit are applied to the first flip-flop circuit of said sequential connection.

Claim 9

A television receiver channel selector for selecting one from among a plurality of channel tuning frequencies, comprising: a tuning circuit tunable to said plurality of channel tuning frequencies, including variable capacitance diodes as tuning elements; a plurality of voltage supply circuits for supplying at outputs thereof tuning voltage corresponding to said plurality of channel tuning frequencies; binary memory circuit means having a plurality of outputs for producing binary coded information signals corresponding to said channel tuning frequencies, said binary memory circuit means comprising a binary counter including N flip-flop circuits for generating a first set of binary coded information signals corresponding to said channel tuning frequencies; binary decoder means having a first plurality of terminals coupled to the corresponding outputs of said binary memory circuit means and a second plurality of terminals coupled to the outputs of said voltage supply circuits; means for selectively connecting the outputs of said voltage supply circuits to said variable capacitance diodes for tuning said tuning circuit to one of said channel tuning frequencies, including means selectively connecting the output of one of said voltage supply circuits to said variable capacitance diodes to tune said tuning circuit to the corresponding channel tuning frequency and disconnecting the outputs of all others of said voltage supply circuits from said variable capacitance diodes, the selective connection of said one voltage supply circuit and disconnection of said all other voltage supply circuits being controlled by a given binary decoder means output; channel selecting means for generating a second set of binary coded information signals corresponding to desired channels to be tuned; pulse generating means coupled to an input of said binary counter to step said counter each time a pulse is produced by said pulse generating means to generate said first set of binary coded information signals; means for comparing said first and second set of binary coded information signals and producing an output signal upon the detection by said comparing means of coincidence between said first and second sets of signals; and means for permitting said pulse generating means to produce a pulse when said comparator means does not produce a coincidence output signal and for preventing said pulse generating means from producing a pulse when said comparator means produces said coincidence output signal.

Claim 10

A television receiver channel selector for selecting one from among a plurality of channel tuning frequencies, comprising: a tuning circuit tunable to said plurality of channel tuning frequencies, including variable capacitance diodes as tuning elements; a plurality of voltage supply circuits for supplying at outputs thereof tuning voltage corresponding to said plurality of channel tuning frequencies; binary memory circuit means having a plurality of outputs for producing binary coded information signals corresponding to said channel tuning frequencies, said binary memory circuit means comprising a binary counter including N flip-flop circuits for generating a first set of binary coded information signals corresponding to said channel tuning frequencies; binary decoder means having a first plurality of terminals coupled to the corresponding outputs of said binary memory circuit means and a second plurality of terminals coupled to the outputs of said voltage supply circuits; means for selectively connecting the outputs of said voltage supply circuits to said variable capacitance diodes for tuning said tuning circuit to one of said channel tuning frequencies, including means selectively connecting the output of one of said voltage supply circuits to said variable capacitance diodes to tune said tuning circuit to the corresponding channel tuning frequency and disconnecting the outputs of all others of said voltage supply circuits from said variable capacitance diodes, the selective connection of said one voltage supply circuit and disconnection of said all other voltage supply circuits being controlled by a given binary decoder means output; channel selecting means for generating a second set of binary coded information signals corresponding to desired channels to be tuned; pulse generating means coupled to an input of said binary counter to step said counter each time a pulse is produced by said pulse generating means to generate said first set of binary coded information signals; means for comparing said first and second set of binary coded information signals and producing an output signal upon the detection by said comparing means of coincidence between said first and second sets of signals; and means for permitting said pulse generating means to produce a pulse when said comparator means does not produce a coincidence output signal and for preventing said pulse generating means from producing a pulse when said comparator means produces said coincidence output signal.

Claim 11

A television receiver channel selector for selecting one from among a plurality of channel tuning frequencies, comprising: a tuning circuit tunable to said plurality of channel tuning frequencies, including variable capacitance diodes as tuning elements; a plurality of preset voltage supply circuits, including preset impedances, for supplying at outputs thereof tuning voltages corresponding to said plurality of channel tuning frequencies; binary memory circuit means having a plurality of outputs for producing binary coded information signals corresponding to said channel tuning frequencies; binary decoder means having a first plurality of terminals coupled to the corresponding outputs of said binary memory circuit means and a second plurality of terminals coupled to the outputs of said voltage supply circuits; means for selectively connecting the outputs of said voltage supply circuits to said variable capacitance diodes for tuning said tuning circuit to one of said channel tuning frequencies, including means selectively connecting the output of one of said voltage supply circuits to said variable capacitance diodes to tune said tuning circuit to the corresponding channel tuning frequency and disconnecting the outputs of all others of said voltage supply circuits from said variable capacitance diodes, the selective connection of said one voltage supply circuit and disconnection of said all other voltage supply circuits being controlled by a signal appearing on a given one of said second plurality of decoder means terminals; a plurality of variable impedance elements each having an intermediate tap, a first terminal connected to ground and a second terminal connected in common to a corresponding second terminal of said binary decoder means and a preset impedance of one of said voltage supply circuits; a plurality of switching elements having control terminals respectively connected to the second plurality of terminals of said binary decoder means, the corresponding one of said switching elements being urged into conductivity by a signal appearing at said given one of said second plurality of decoder terminals; and a plurality of indicating means connected in series with said respective switching elements; wherein said selective connection means comprises a diode logic OR gate having an output coupled in common to said variable capacitance diodes and having a plurality of inputs coupled to corresponding ones of the intermediate taps of said variable impedance elements.

Claim 12

A television receiver channel selector for selecting one from among a plurality of channel tuning frequencies, comprising: a tuning circuit tunable to said plurality of channel tuning frequencies, including variable capacitance diodes as tuning elements; a plurality of preset voltage supply circuits, including preset impedances, for supplying at outputs thereof tuning voltages corresponding to said plurality of channel tuning frequencies; binary memory circuit means having a plurality of outputs for producing binary coded information signals corresponding to said channel tuning frequencies; binary decoder means having a first plurality of terminals coupled to the corresponding outputs of said binary memory circuit means and a second plurality of terminals coupled to the outputs of said voltage supply circuits; means for selectively connecting the outputs of said voltage supply circuits to said variable capacitance diodes for tuning said tuning circuit to one of said channel tuning frequencies, including means selectively connecting the output of one of said voltage supply circuits to said variable capacitance diodes to tune said tuning circuit to the corresponding channel tuning frequency and disconnecting the outputs of all others of said voltage supply circuits from said variable capacitance diodes, the selective connection of said one voltage supply circuit and disconnection of said all other voltage supply circuits being controlled by a signal appearing on a given one of said second plurality of decoder means terminals; a plurality of variable impedance elements each having an intermediate tap, a first terminal connected to ground and a second terminal connected in common to a corresponding second terminal of said binary decoder means and a preset impedance of one of said voltage supply circuits; a plurality of switching elements having control terminals respectively connected to the second plurality of terminals of said binary decoder means, the corresponding one of said switching elements being urged into conductivity by a signal appearing at said given one of said second plurality of decoder terminals; and a plurality of indicating means connected in series with said respective switching elements; wherein said selective connection means comprises a diode logic OR gate having an output coupled in common to said variable capacitance diodes and having a plurality of inputs coupled to corresponding ones of the intermediate taps of said variable impedance elements.

Claim 13

A television receiver channel selector for selecting one from among a plurality of channel tuning frequencies, comprising: a tuning circuit tunable to said plurality of channel tuning frequencies, including variable capacitance diodes as tuning elements; a plurality of preset voltage supply circuits, including preset impedances, for supplying at outputs thereof tuning voltages corresponding to said plurality of channel tuning frequencies; binary memory circuit means having a plurality of outputs for producing binary coded information signals corresponding to said channel tuning frequencies, said binary memory circuit comprising a binary up-down counter including N flip-flops, a pulse generator circuit for supplying pulses to said binary counter, and switching means for reversibly operating said up-down counter; binary decoder means having a first plurality of terminals coupled to the corresponding outputs of said binary memory circuit means and a second plurality of terminals coupled to the outputs of said voltage supply circuits; means for selectively connecting the outputs of said voltage supply circuits to said variable capacitance diodes for tuning said tuning circuit of one of said channel tuning frequencies, including means selectively connecting the output of one of said voltage supply circuits to said variable capacitance diodes to tune said tuning circuits to the corresponding channel tuning frequency and disconnecting the outputs of all others of said voltage supply circuits from said variable capacitance diodes, the selective connection of said one voltage supply circuit and disconnection of said all other voltage supply circuits being controlled by a signal appearing on a given one of said second plurality of decoder means terminals; and a plurality of variable impedance elements each having an intermediate tap, a first terminal connected to ground and a second terminal connected in common to a corresponding second terminal of said binary decoder means and a preset impedance of one of said voltage supply circuits; wherein said selective connection means comprises a diode logic OR gate having an output coupled in common to said variable capacitance diodes and having a plurality of inputs coupled to corresponding ones of the intermediate taps of said variable impedance elements.

Claim 14

A television receiver channel selector for selecting one from among a plurality of channel tuning frequencies, comprising: a tuning circuit tunable to said plurality of channel tuning frequencies, including variable capacitance diodes as tuning elements; a plurality of preset voltage supply circuits, including preset impedances, for supplying at outputs thereof tuning voltages corresponding to said plurality of channel tuning frequencies; binary memory circuit means having a plurality of outputs for producing binary coded information signals corresponding to said channel tuning frequencies, said binary memory circuit comprising a binary up-down counter including N flip-flops, a pulse generator circuit for supplying pulses to said binary counter, and switching means for reversibly operating said up-down counter; binary decoder means having a first plurality of terminals coupled to the corresponding outputs of said binary memory circuit means and a second plurality of terminals coupled to the outputs of said voltage supply circuits; means for selectively connecting the outputs of said voltage supply circuits to said variable capacitance diodes for tuning said tuning circuit of one of said channel tuning frequencies, including means selectively connecting the output of one of said voltage supply circuits to said variable capacitance diodes to tune said tuning circuits to the corresponding channel tuning frequency and disconnecting the outputs of all others of said voltage supply circuits from said variable capacitance diodes, the selective connection of said one voltage supply circuit and disconnection of said all other voltage supply circuits being controlled by a signal appearing on a given one of said second plurality of decoder means terminals; and a plurality of variable impedance elements each having an intermediate tap, a first terminal connected to ground and a second terminal connected in common to a corresponding second terminal of said binary decoder means and a preset impedance of one of said voltage supply circuits; wherein said selective connection means comprises a diode logic OR gate having an output coupled in common to said variable capacitance diodes and having a plurality of inputs coupled to corresponding ones of the intermediate taps of said variable impedance elements.

Claim 15

A television receiver channel selector for selecting one from among a plurality of channel tuning frequencies, comprising: a tuning circuit tunable to said plurality of channel tuning frequencies, including variable capacitance diodes as tuning elements; a plurality of preset voltage supply circuits, including preset impedances, for supplying at outputs thereof tuning voltages corresponding to said plurality of channel tuning frequencies; binary memory circuit means having a plurality of outputs for producing binary coded information signals indicating pure binary numbers and corresponding to said channel tuning frequencies, said binary memory circuit comprising a binary up-down counter including N flip-flops, a pulse generator circuit for supplying pulses to said binary counter, and switching means for reversibly operating said up-down counter; binary decoder means having a first plurality of terminals coupled to the corresponding outputs of said binary memory circuit means and a second plurality of terminals coupled to the outputs of said voltage supply circuits; means for selectively connecting the outputs of said voltage supply circuits to said variable capacitance diodes for tuning said tuning circuit to one of said channel tuning frequencies, including means for selectively connecting the output of one of said voltage supply circuits to said variable capacitance diodes to tune said tuning circuit to the corresponding channel tuning frequency and disconnecting the outputs of all others of said voltage supply circuits from said variable capacitance diodes, the selective connection of said one voltage supply circuit and disconnection of said all other voltage supply circuits being controlled by a signal appearing on a given one of said second plurality of decoder means terminals; and a plurality of variable impedance elements connected in parallel across said preset voltage supply circuits and having intermediate taps connected to the second plurality of terminals of said binary decoder means; wherein said selective connecting means includes a diode logic OR gate comprising a plurality of diodes having a plurality of input terminals connected to the respective intermediate taps of said impedance elements and having an output terminal connected to said variable capacitance diodes.

Claim 16

A television receiver channel selector for selecting one from among a plurality of channel tuning frequencies, comprising: a tuning circuit tunable to said plurality of channel tuning frequencies, including variable capacitance diodes as tuning elements; a plurality of preset voltage supply circuits, including preset impedances, for supplying at outputs thereof tuning voltages corresponding to said plurality of channel tuning frequencies; binary memory circuit means having a plurality of outputs for producing binary coded information signals indicating pure binary numbers and corresponding to said channel tuning frequencies, said binary memory circuit comprising a binary up-down counter including N flip-flops, a pulse generator circuit for supplying pulses to said binary counter, and switching means for reversibly operating said up-down counter; binary decoder means having a first plurality of terminals coupled to the corresponding outputs of said binary memory circuit means and a second plurality of terminals coupled to the outputs of said voltage supply circuits; means for selectively connecting the outputs of said voltage supply circuits to said variable capacitance diodes for tuning said tuning circuit to one of said channel tuning frequencies, including means for selectively connecting the output of one of said voltage supply circuits to said variable capacitance diodes to tune said tuning circuit to the corresponding channel tuning frequency and disconnecting the outputs of all others of said voltage supply circuits from said variable capacitance diodes, the selective connection of said one voltage supply circuit and disconnection of said all other voltage supply circuits being controlled by a signal appearing on a given one of said second plurality of decoder means terminals; and a plurality of variable impedance elements connected in parallel across said preset voltage supply circuits and having intermediate taps connected to the second plurality of terminals of said binary decoder means; wherein said selective connecting means includes a diode logic OR gate comprising a plurality of diodes having a plurality of input terminals connected to the respective intermediate taps of said impedance elements and having an output terminal connected to said variable capacitance diodes.