Biquad filter
AssigneesKabushiki Kaisha Toshiba, Toshiba Electronic Devices & Storage Corporation
InventorMakoto MORITA
Life of this patent
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Abstract
According to one embodiment, in a biquad filter, an output terminal of a first integrator is connected to an input terminal in a negative pole side of a second integrator, an output terminal of the first integrator is connected to a first input terminal in a negative pole side of an adder through the inversion amplifier, an output terminal of the second integrator is connected to a second input terminal in the negative pole side of the adder, an input terminal to which an input signal is input is connected to a third input terminal in the negative side of the adder, and an output terminal of the adder is connected to an input terminal in a negative pole side of the first integrator.
Claims15
A biquad filter comprising:
- a first integrator including a first operational amplifier, and a first variable resistor and a first condenser connected to the first operational amplifier;
- a second integrator including a second operational amplifier, and a second variable resistor and a second condenser connected to the second operational amplifier;
- an adder including a third operational amplifier and a plurality of resistors connected to the third operational amplifier;
- and
- an inversion amplifier having a 1× amplification rate, wherein
- an output terminal of the first integrator is connected to an input terminal in a negative pole side of the second integrator,
- the output terminal of the first integrator is connected to a first input terminal in a negative pole side of the adder through the inversion amplifier, an output terminal of the second integrator is connected to a second input terminal in the negative pole side of the adder,
- an input terminal to which an input signal is input is connected to a third input terminal in the negative side of the adder, and
- an output terminal of the adder is connected to an input terminal in a negative pole side of the first integrator.
A biquad filter, comprising:
- a first integrator including a first fully-differential operational amplifier, a first variable resistor connected to the first fully-differential operational amplifier, and a first condenser connected to the first fully-differential operational amplifier;
- a second integrator including a second fully-differential operational amplifier, a second variable resistor connected to the second fully-differential operational amplifier, and a second condenser connected to the second fully-differential operational amplifier;
- and
- an adder including a third fully-differential operational amplifier and a plurality of resistors connected to the third fully-differential operational amplifier, wherein
- an output terminal in a positive pole side of the first integrator is connected to an input terminal in a negative pole side of the second integrator,
- an output terminal in a positive pole side of the second integrator is connected to a first input in a positive pole side of the adder,
- an output terminal in a negative pole side of the first integrator is connected to an input terminal in a positive pole side of the second integrator,
- an output terminal in a negative pole side of the first integrator is connected to a first input terminal in a negative pole side of the adder,
- an output terminal in a positive pole side of the second integrator is connected to a second input terminal in the negative pole side of the adder,
- an output terminal in a negative pole side of the second integrator is connected to a second input terminal in the positive pole side of the adder,
- a first input terminal to which one of positive phase and negative phase of differential input signals is input is connected to a third input terminal in the negative pole side of the adder,
- a second input terminal to which the other one of the positive phase and negative phase of differential input signals is connected to a third input terminal in the positive pole side of the adder,
- an output terminal in the positive pole side of the adder is connected to an input terminal in a positive pole side of the first integrator, and
- an output terminal in the negative pole side of the adder is connected to an input terminal in a positive pole side of the first integrator.
Dependencies are inferred from the claim text.