Neutralized amplifier circuit

Claim 2

A neutralized amplifier circuit including in combination a semiconductive amplifying device having an input electrode and an output electrode, said device having an internal capacitive effect between the input and output electrodes which varies with the voltage therebetween; a variable capacitance diode having a capacitive effect which varies with the voltage across the diode, said diode being coupled between the output electrode and the input electrode of said semiconductive amplifying device whereby the internal capacitive effect of said semiconductive amplifying device is substantially neutralized over a wide dynamic range; an output transformer having a primary winding and a secondary winding; one of the windings of said transformer being coupled to the output electrode of said semiconductive amplifying device and to a point of AC reference potential whereby the capacitive effect of the semiconductive amplifying device and said one of the windings of said transformer provide a first AC series circuit between the input electrode of the semiconductive amplifying device and the point of AC reference potential; and the other of the windings of said transformer being coupled to the variable capacitance diode and to said point of AC reference potential whereby the variable capacitance diode and said other of the windings of said transformer provide a second AC series circuit between the input electrode of the semiconductive amplifying device and said point of AC reference potential.

Claim 3

A neutralized amplifier circuit in accordance with claim 1 wherein said semiconductive amplifying device is a bipolar transistor having emitter, base, and collector electrodes; and said base electrode is the input electrode and said collector electrode is the output electrode.

Claim 4

A neutralized amplifier circuit in accordance with claim 1 wherein said semiconductive amplifying device is a field effect transistor having source, drain, and gate electrodes; and said gate electrode is the input electrode and one of said remaining electrodes is the output electrode.

Claim 5

A neutralized amplifier circuit including in combination first and second semiconductive amplifying devices each having an input electrode and an output electrode, each of said devices having an internal capacitive effect between the input and output electrodes which varies with the voltage therebetween; an input transformer having a primary winding and a secondary winding; an output transformer having a primary winding and a secondary winding; one end of the secondary winding of the input transformer being coupled to the input electrode of the first semiconductive amplifying device and the other end of the secondary winding of the input transformer being coupled to the input electrode of the second semiconductive amplifying device; one end of the primary winding of the output transformer being coupled to the output electrode of the first semiconductive amplifying device and the other end of the primary winding of the output transformer being coupled to the output electrode of the second semiconductive amplifying device; a first variable capacitance diode having a capacitive effect which varies with the voltage across the diode, said first diode being coupled between the one end of the primary winding of the output transformer and the input electrode of said second semiconductive amplifying device; and a second variable capacitance diode having a capacitive effect which varies with the voltage across the diode, said second diode being coupled between the other end of the primary winding of the output transformer and the input electrode of said first semiconductive amplifying device.

Claim 6

A neutralized amplifier circuit including in combination first and second semiconductive amplifying devices each having an input electrode and an output electrode, each of said devices having an internal capacitive effect between the input and output electrodes which varies with the voltage therebetween; an input transformer having a primary winding and a secondary winding; an output transformer having a primary winding and a secondary winding; one end of the secondary winding of the input transformer being coupled to the input electrode of the first semiconductive amplifying device and the other end of the secondary winding of the input transformer being coupled to the input electrode of the second semiconductive amplifying device; one end of the primary winding of the output transformer being coupled to the output electrode of the first semiconductive amplifying device and the other end of the primary winding of the output transformer being coupled to the output electrode of the second semiconductive amplifying device; a first variable capacitance diode having a capacitive effect which varies with the voltage across the diode, said first diode being coupled between the one end of the primary winding of the output transformer and the input electrode of said second semiconductive amplifying device; and a second variable capacitance diode having a capacitive effect which varies with the voltage across the diode, said second diode being coupled between the other end of the primary winding of the output transformer and the input electrode of said first semiconductive amplifying device.

Claim 7

A neutralized amplifier circuit in accordance with claim 4 including a first capacitance connected across the secondary winding of the input transformer for providing therewith a tuned input circuit; and a second capacitance connected across the primary winding of the output transformer for providing therewith a tuned output circuit.

Claim 8

A neutralized amplifier circuit in accordance with claim 5 wherein each of said semiconductive amplifying devices is a bipolar transistor having emitter, base, and collector electrodes; and the base electrode of a transistor is the input electrode and the collector electrode of a transistor is the output electrode; and including first impedance means connecting the emitter electrode of the first transistor to a source of reference potential; and second impedance means connecting the emitter electrode of the second transistor to the source of reference potential.