Voltage-controlled attenuator and balanced mixer

Claim 2

A voltage-controlled attenuator comprising: a signal source of predetermined frequency range; a voltage-dividing network having an input terminal and an output terminal; an inverting transformer coupling said signal source to said input terminal of said voltage-dividing network; a summing junction; a voltage variable resistance element coupling said output terminal of said voltage-dividing network to said summing junction; a noninverting circuit branch comprising a series resistor coupling said signal source to said summing junction; a source of impedance control voltage; and means for connecting said source of impedance control voltage to said voltage variable resistance element, whereby the attenuation of a signal being transmitted from said signal source to said summing junction is controlled by said source of impedance control voltage.

Claim 3

A voltage-controlled attenuator as defined in claim 1 wherein said voltage variable resistance element comprises a semiconductor device biased by said impedance control voltage.

Claim 4

A voltage-controlled attenuator as defined in claim 2 wherein said noninverting circuit branch further comprises means for compensating for any phase shift in signals coupled to said compensating for any phase shift in signals coupled to said load input terminal through said transformer, whereby noninverted signals coupled to said summing junction through said circuit branch are 180* out of phase with signals coupled to said summing junction through said transformer.

Claim 5

A voltage-controlled attenuator as defined in claim 3 wherein said phasE-shift-compensating means comprises a reactance circuit.

Claim 6

A voltage-controlled attenuator as defined in claim 4 wherein said reactance circuit is connected in series with said resistor.

Claim 7

A voltage-controlled attenuator as defined in claim 5 wherein a load is connected to said summing junction.

Claim 8

A voltage-controlled attenuator as defined in claim 5 wherein a load is coupled to said voltage dividing network by a second transformer having its primary winding connected to said output terminal of said voltage-dividing network.

Claim 9

A voltage-controlled attenuator for coupling an alternating signal from a source to a load, comprising an inverting transformer having a primary winding adapted to have end terminals thereof connected to said signal source, and secondary winding having only end terminals, a pair of resistors connected in series between said end terminals of said secondary winding to form a voltage divider to provide at an output terminal between said pair of resistors a predetermined fraction of an inverted signal induced across said secondary winding, voltage-controlled resistance means having first and second terminals, said means being responsive to a bias voltage for controlling the resistance between said first and second terminals thereof, said first terminal being coupled to said output terminal of said voltage divider formed by said pair of resistors, impedance means coupling one end terminal of said primary winding to said second terminal of said bias-controlled resistance means, means for providing said bias voltage to said voltage-controlled resistance means, and means for coupling said load between one of said first and second terminals of said voltage-controlled resistance means and one of said end terminals of said secondary winding.

Claim 10

A voltage-controlled attenuator for coupling an alternating signal from a source to a load, comprising an inverting transformer having a primary winding adapted to have end terminals thereof connected to said signal source, and secondary winding having only end terminals, a pair of resistors connected in series between said end terminals of said secondary winding to form a voltage divider to provide at an output terminal between said pair of resistors a predetermined fraction of an inverted signal induced across said secondary winding, voltage-controlled resistance means having first and second terminals, said means being responsive to a bias voltage for controlling the resistance between said first and second terminals thereof, said first terminal being coupled to said output terminal of said voltage divider formed by said pair of resistors, impedance means coupling one end terminal of said primary winding to said second terminal of said bias-controlled resistance means, means for providing said bias voltage to said voltage-controlled resistance means, and means for coupling said load between one of said first and second terminals of said voltage-controlled resistance means and one of said end terminals of said secondary winding.

Claim 11

The combination of claim 8 wherein said voltage-controlled resistance means comprises a forward biased semiconductor diode.

Claim 12

The combination of claim 8 wherein said impedance means comprises a resistor.

Claim 13

The combination of claim 10 wherein said coupling means is comprised of a transformer having a primary winding with end terminals thereof connected to ends of one of said pair of resistors forming said voltage divider and a secondary winding having end terminals thereof adapted to be connected to said load.