Signal control circuit

Claim 2

A signal control circuit comprising two electron conducting devices and first and second terminals, each of said devices having a first electrode, a second electrode and a third electrode, respectively, said first electrode of said first electron conducting device being connected to said second electrode of said second electron conducting device to form said first terminal and said second electrode of said first electron conducting device and said first electrode of said second electron conducting device being connected to form said second terminal, and a control signal input means being connected to said third electrodes of said first and second electron conducting devices for supplying a control signal from a control signal source to said third electrode, and an input signal means, being coupled to said first and second terminals, whereby the amplitude of said input signal applied to said terminals is controlled in accordance with a control signal applied to said third electrodes.

Claim 3

A signal control circuit as claimed in claim 1, wherein said first and second electron conducting device are transistors.

Claim 4

A signal control circuit as claimed in claim 1, wherein said first and second electron conducting devices are transistors having the same characteristics.

Claim 5

A signal control circuit as claimed in claim 1, wherein said electron conducting devices are first and second transistors and said first electrodes are collectors of the first and second transistors, and said second electrodes are emitters of said first and second transistors, and said third electrodes are bases of said first and second transistors.

Claim 6

A signal control circuit as claimed in claim 4, wherein said base electrodes of said first and second transistors are connected to each other.

Claim 7

A signal control circuit as claimed in claim 4, in which said input signal means is an input terminal, said circuit further comprising an output terminal, a resistor which is connected between said input and output terminals and a capacitor which is connected between said output terminal and said first terminal, said second terminal of said transistors being grounded and said bases of said first and second transistors being connected to each other.

Claim 8

A signal control circuit as claimed in claim 6, in which said control signal input means comprises a constant current circuit which is coupled to said bases of said first and second transistors.

Claim 9

A signal control circuit as claimed in claim 7, wherein said constant current circuit includes a resistor.

Claim 10

A signal control circuit as claimed in claim 7, wherein said constant current circuit comprises a diode, a resistor, a third transistor, and a fourth transistor, a direct current voltage source to which the emitter of said third transistor is connected, the collector of said third transistor being connected to said bases of said first and second transistors, said diode being connected between the base and emitter of said third transistor, the collector of said fourth transistor being connected to the base of said third transistor, the emitter of said fourth transistor being grounded through said resistor, and the base of said fourth transistor being a control signal input terminal.

Claim 11

A signal control circuit as claimed in claim 4, in which said input signal means is an input terminal, said circuit further comprising an output terminal, a resistor connected between said input and output terminals and a capacitor which is connected between said output terminal and said first terminal, said second terminal of said transistors being grounded, and a resistor through which said bases of said first and second transistors are coupled to said control signal input means, respectively.

Claim 12

A signal control circuit comprising: an input terminal; an output terminal; a variable resistance circuit means which comprises at least first and second transistors, the collector of said first transistor being connected to the emitter of said second transistor, the emitter of said first transistor being connected to the collector of said second transistor and the junction point of said emitter of said first transistor and said collector of said second transistor being grounded, and bases of said first and second transistors being connected to each other; a constant current circuit means coupled to said variable resistance circuit for supplying a control current to said bases of said transistors; an amplifier means having an input and output terminal; a rectifier means coupled to said output terminal of said amplifier means and to said constant current circuit means for receiving said amplified signal and supplying a control signal to said constant current circuit means; an input resistance means connected between said input terminal and the input terminal of said amplifier means; and a capacitance means connected between said input terminal of said amplifier means and the junction of said collector of said first transistor and said emitter of said second transistor of said variable resistance circuit means.

Claim 13

A signal control circuit comprising: an input terminal; an output terminal; a variable resistance circuit means which comprises at least first and second transistors, the collector of said first transistor being connected to the emitter of said second transistor, the emitter of said first transistor being connected to the collector of said second transistor and the junction point of said emitter of said first transistor and said collector of said second transistor being grounded, and bases of said first and second transistors being connected to each other; a constant current circuit means coupled to said variable resistance circuit for supplying a control current to said bases of said transistors; an amplifier means having an input and output terminal; a rectifier means coupled to said output terminal of said amplifier means and to said constant current circuit means for receiving said amplified signal and supplying a control signal to said constant current circuit means; an input resistance means connected between said input terminal and the input terminal of said amplifier means; and a capacitance means connected between said input terminal of said amplifier means and the junction of said collector of said first transistor and said emitter of said second transistor of said variable resistance circuit means.

Claim 14

A signal control circuit as claimed in claim 11, wherein said constant current circuit means is a resistor.

Claim 15

A signal control circuit as claimed in claim 11, wherein said constant current circuit means comprises a diode, a resistor, a third transistor, and a fourth transistor, a direct current voltage source to which the emitter of said third transistor is connected, the collector of said third transistor being connected to said bases of said first and second transistors, said diode being connected between the base and emitter of said third transistor, the collector of said fourth transistor being connected to the base of said third transistor, the emitter of said fourth transistor being grounded through said resistor, and the base of said fourth transistor being a control signal input terminal.

Claim 16

A signal control circuit as claimed in claim 13, further including two further resistors, one of said further resistors being connected between said emitter of said third transistor and said direct current voltage source, and the other further resistor being connected between one end of said diode aNd said direct current voltage source.

Claim 17

A signal control circuit as claimed in claim 13, further including a fifth transistor having the base connected to the collector of said third transistor, the collector connected to said direct current voltage source, and the emitter connected to said bases of said first and second transistors.

Claim 18

A signal control circuit as claimed in claim 13, wherein said rectifier means comprising a rectifying transistor, the collector of said rectifying transistor being connected to said direct current source, and a rectifying capacitor which is connected between the emitter of said rectifying transistor and ground.

Claim 19

A signal control circuit as claimed in claim 13, wherein said rectifier means comprises a rectifying diode and a parallel connection of a rectifying capacitor and a rectifying resistor.