Gyrator circuits comprising operational amplifiers and oscillating utilizing same

Claim 2

A gyrator circuit, comprising: first and second operational amplifiers, each having an inverting input terminal, a non-inverting input terminal, and an output terminal; first and second resistive impedances connected together to define a common junction therebetween and connected in series between the output terminal of said first operational amplifier and a circuit reference point, said first resistive impedance being connected to said circuit reference point; connecting leads connecting said common junction to both said inverting input terminal of said first operational amplifier and said non-inverting input terminal of said second operational amplifier; a third resistive impedance connected in series between said output terminal of said first operational amplifier and the inverting input terminal of said second operational amplifier; a capacitive impedance connected in negative feEdback relationship between the output terminal and the inverting input terminal of said second operational amplifier; and a further resistive impedance connected in feedback relationship between the output terminal of said second operational amplifier and the non-inverting input terminal of said first operational amplifier; wherein said non-inverting input terminal of said first operational amplifier constitutes an input terminal for said circuit.

Claim 3

The gyrator circuit according to claim 1 arranged to simulate a two-terminal grounded inductance, wherein said two terminals comprise the non-inverting input terminal of said first operational amplifier and said circuit reference point, and wherein said circuit reference point constitutes circuit ground.

Claim 4

The gyrator according to claim 1 interconnected with another said gyrator to simulate a pair of mutually coupled inductors, wherein said first resistive impedance in each gyrator is replaced by a common resistive network coupling the common junctions of each gyrator to one another and to circuit ground.

Claim 5

The gyrator according to claim 1 interconnected with another said gyrator to simulate a floating inductor, the two gyrators sharing their first resistive impedance in common, said common first resistive impedance being connected between the common junction of each gyrator circuit.

Claim 6

The gyrator circuit according to claim 1 further comprising a potentiometer having an adjustable slider arm and connected across said first and second resistive impedances, and wherein said non-inverting input terminal of said second operational amplifier is connected to said slider arm instead of to said common junction.

Claim 7

The gyrator circuit according to claim 1 arranged to oscillate in conjunction with a capacitor connected between said circuit reference point and the non-inverting input terminal of said first operational amplifier, said circuit further comprising: a feedback path comprising first and second resistors connected in series between the output terminal and non-inverting input terminal of said first operational amplifier; and a clamping circuit connected between said circuit reference point and a point in said feedback path between said first and second resistors.

Claim 8

The gyrator according to claim 6 wherein said clamping circuit is referenced to a controllably variable voltage.

Claim 9

The gyrator circuit according to claim 1 arranged to oscillate in conjunction with a capacitor connected between said circuit reference point and the non-inverting input terminal of said first operational amplifier, said circuit further comprising a resistive feedback path connected in series between the output terminal and non-inverting input terminal of said operational amplifier.

Claim 10

A gyrator circuit, comprising: first and second operational amplifiers, each having an inverting input terminal, a non-inverting input terminal, and an output terminal; a first resistive impedance and a capacitive impedance connected together to define a common junction therebetween and connected in series between the output terminal of said first operational amplifier and a circuit reference point with said first resistive impedance being connected to said reference point; connecting leads connecting said common junction to both said inverting input terminal of said first operational amplifier and said non-inverting input terminal of said second operational amplifier; a second resistive impedance connected in series between said output terminal of said first operational amplifier and inverting input terminal of said second operational amplifier; a third resistive impedance connected in negative feedback relationship between the output terminal and the inverting input terminal of said second operational amplifier; and a further resistive impedance connected in feedback relationship between the output terminal of said second operational amplifier and the non-inverting input terminal of said First operational amplifier; wherein said non-inverting input terminal of said first operational amplifier constitutes an input terminal for said circuit.

Claim 11

A gyrator circuit, comprising: first and second operational amplifiers, each having an inverting input terminal, a non-inverting input terminal, and an output terminal; a first resistive impedance and a capacitive impedance connected together to define a common junction therebetween and connected in series between the output terminal of said first operational amplifier and a circuit reference point with said first resistive impedance being connected to said reference point; connecting leads connecting said common junction to both said inverting input terminal of said first operational amplifier and said non-inverting input terminal of said second operational amplifier; a second resistive impedance connected in series between said output terminal of said first operational amplifier and inverting input terminal of said second operational amplifier; a third resistive impedance connected in negative feedback relationship between the output terminal and the inverting input terminal of said second operational amplifier; and a further resistive impedance connected in feedback relationship between the output terminal of said second operational amplifier and the non-inverting input terminal of said First operational amplifier; wherein said non-inverting input terminal of said first operational amplifier constitutes an input terminal for said circuit.

Claim 12

The gyrator circuit according to claim 9 arranged to simulate a two-terminal grounded inductance, wherein said two terminals comprise the non-inverting input terminal of said first operational amplifier and said circuit reference point and wherein said circuit reference point constitutes circuit ground.

Claim 13

The gyrator according to claim 9 interconnected with another said gyrator to simulate a pair of mutually coupled inductors, wherein said first resistive impedance in each gyrator is replaced by a common resistive network coupling the common junctions of said gyrators to one another and to circuit ground.

Claim 14

The gyrator according to claim 9 interconnected with another said gyrator to simulate a floating inductor, the two gyrators sharing their first resistive impedance in common, said common first resistive impedance being connected between the common junction of each gyrator circuit.

Claim 15

The gyrator circuit according to claim 9 further comprising a potentiometer having an adjustable slider arm and connected across said capactive impedance and said resistive impedance, and wherein said non-inverting input terminal of said second operational amplifier is connected to said slider arm instead of to said common junction.

Claim 16

The gyrator circuit according to claim 9 arranged to oscillate in conjunction with a capacitor connected between said circuit reference point and the non-inverting input terminal of said first operational amplifier, said circuit further comprising: a feedback path comprising first and second resistors connected in series between the output terminal and non-inverting input terminal of said first operational amplifier; and a clamping circuit connected between said circuit reference point and a point in said feedback path between said first and second resistors.

Claim 17

The gyrator circuit according to claim 9 arranged to oscillate in conjunction with a capacitor connected between said circuit reference point and the non-inverting input terminal of said first operational amplifier, said circuit further comprising a resistive feedback path connected in series between the output terminal and non-inverting input terminal of said first operational amplifier.

Claim 18

A gyrator circuit comprising: first and second differential operational amplifiers, each having an inverting input terminal, a non-inverting input terminal, and an output terminal; voltage divider means connected between the output terminal of said first operational amplifier and circuit ground; a first circuit lead connected between a first point on said voltage divider means and the inverting input terminal of said first operational amplifier; a second circuit lead connected between a second point on said voltage divider means and the non-inverting input terminal of said second operational amplifier; a resistive impedance connected in series between said output terminal of said first operational amplifier and the inverting input terminal of said second operational amplifier; a first feedback impedance connected between the output terminal and inverting input terminal of said second operational amplifier; and a further resistive feedback impedance connected between the output terminal of said second operational amplifier and the non-inverting input terminal of said first operational amplifier; wherein said circuit simulates an inductive element using only one capacitive element; and wherein one of said first feedback impedance and said voltage divider means includes said one capacitive element; said non-inverting input terminal of said first operational amplifier constitutes an input terminal for said circuit.

Claim 19

A gyrator circuit comprising: first and second differential operational amplifiers, each having an inverting input terminal, a non-inverting input terminal, and an output terminal; voltage divider means connected between the output terminal of said first operational amplifier and circuit ground; a first circuit lead connected between a first point on said voltage divider means and the inverting input terminal of said first operational amplifier; a second circuit lead connected between a second point on said voltage divider means and the non-inverting input terminal of said second operational amplifier; a resistive impedance connected in series between said output terminal of said first operational amplifier and the inverting input terminal of said second operational amplifier; a first feedback impedance connected between the output terminal and inverting input terminal of said second operational amplifier; and a further resistive feedback impedance connected between the output terminal of said second operational amplifier and the non-inverting input terminal of said first operational amplifier; wherein said circuit simulates an inductive element using only one capacitive element; and wherein one of said first feedback impedance and said voltage divider means includes said one capacitive element; said non-inverting input terminal of said first operational amplifier constitutes an input terminal for said circuit.

Claim 20

The gyrator according to claim 16 wherein said second point on said voltage divider means is adjustable to permit selective control of the overalL input conductance of said circuit.

Claim 21

The gyrator according to claim 16 wherein said voltage divider means is entirely resistive, wherein said first feedback impedance includes a capacitive element, and wherein said second point on said voltage divider means is adjustable along said voltage divider means.