Balancing amplifier

Claim 2

A balancing amplifier comprising a single input terminal for connection to a signal to be balanced, a pair of transistors connected as a differential amplifier with a control electrode of one transistor of the differential amplifier coupled to said input terminal via an input impedance element, each of the transistors having a load circuit provided with a transistor arranged as a voltage follower for supplying, by means of a negative feedback network, a negative feedback voltage to the control electrode of the transistor of the differential amplifier to which the network is connected in response to a signal at the input terminal.

Claim 3

A balancing amplifier as claimed in claim 1 further comprising a voltage dropper device connected between an output electrode of the voltage follower transistor and the negative feedback network.

Claim 4

A balancing amplifier as claimed in claim 2 wherein the voltage dropper device comprises a resistor shunted by a capacitor.

Claim 5

A balancing amplifier as claimed in claim 2 wherein the voltage dropper device comprises a zener diode.

Claim 6

A balancing amplifier as claimed in claim 2 wherein the voltage dropper device comprises at least one "normal" diode.

Claim 7

An amplifier as claimed in claims 1 or 2 further comprising means connecting the output electrodes of the transistors arranged as voltage followers to a voltage source via a network having a high impedance.

Claim 8

An amplifier as claimed in claim 6 wherein the network having a high impedance comprises a resistor.

Claim 9

An amplifier as claimed in claim 6 wherein the network having a high impedance comprises a current generator.

Claim 10

A balancing amplifier as claimed in claims 1 or 2 wherein the transistors comprise bipolar transistors.

Claim 11

A balancing amplifier as claimed in claims 1 or 2 wherein the feedback network comprises a resistor.

Claim 12

A balancing amplifier as claimed in claims 1 or 2 further comprising a capacitor coupling a control electrode of the other transistor of said pair of transistors to a source of fixed voltage.

Claim 13

A balancing amplifier comprising, first and second transistors coupled together to form a differential amplifier, a single input terminal for connection to a source of analog signal, an impedance element coupling the input terminal to a control electrode of said first transistor, means for AC coupling a control electrode of the second transistor to a point of reference voltage, first and second negative feedback voltage networks coupling output electrodes of said first and second transistors to the control electrodes thereof, respectively, each of said feedback networks including a transistor connected as a voltage follower with an output electrode thereof coupled to the control electrode of the corresponding transistor of the differential amplifier, and first and second output terminals coupled respectively to the output electrodes of the voltage follower transistors to provide first and second output signals of opposite phase.

Claim 14

A balancing amplifier comprising, first and second transistors coupled together to form a differential amplifier, a single input terminal for connection to a source of analog signal, an impedance element coupling the input terminal to a control electrode of said first transistor, means for AC coupling a control electrode of the second transistor to a point of reference voltage, first and second negative feedback voltage networks coupling output electrodes of said first and second transistors to the control electrodes thereof, respectively, each of said feedback networks including a transistor connected as a voltage follower with an output electrode thereof coupled to the control electrode of the corresponding transistor of the differential amplifier, and first and second output terminals coupled respectively to the output electrodes of the voltage follower transistors to provide first and second output signals of opposite phase.

Claim 15

An amplifier as claimed in claim 12 further comprising a current generator, and means coupling a common electrode of said first and second transistors to a source of DC supply voltage via said current generator.

Claim 16

An amplifier as claimed in claim 12 wherein said impedance element comprises a resistor with a resistance value R A and the first negative feedback network includes a feedback resistor having a resistance value R B connected between the output electrode of the voltage follower transistor of the first negative feedback network and the control electrode of said first transistor, and wherein R B >R A .

Claim 17

An amplifier as claimed in claim 14 wherein the ratio of R B to R A is approximately 10 to 1 and the gain of the amplifier is determined primarily by said ratio.

Claim 18

An amplifier as claimed in claim 14 further comprising a voltage dropping device connected in series with said feedback resistor between said voltage follower transistor output electrode and said first transistor control electrode and in the order recited.

Claim 19

An amplifier as claimed in claim 16 wherein said voltage dropping device comprises a resistor and capacitor connected in parallel.

Claim 20

An amplifier as claimed in claim 12 wherein said AC coupling means comprises a capacitor.

Claim 21

An amplifier as claimed in claims 12, 14, 16 or 18 further comprising current generator means coupled between the output electrodes of the voltage follower transistors and a source of reference voltage.

Claim 22

An amplifier as claimed in claims 12 or 18 wherein the impedance element comprises a passive circuit element having relatively fixed parameters for impeding current flow.