Patent ID: 8665129

Claim:
A complex second-order integrator, comprising: first and second second-order integrators; and first and second coupling circuits configured to couple the first and second second-order integrators together, wherein each of the first and second second-order integrators includes an operational amplifier, a first resistance element connected between a first node and a signal input terminal of the second-order integrator, a second resistance element connected between the first node and an inverted input terminal of the operational amplifier, a first capacitance element connected between the first node and a ground, a second capacitance element connected between a second node and the inverted input terminal of the operational amplifier, a third capacitance element connected between the second node and an output terminal of the operational amplifier, a third resistance element connected between the second node and the ground, and a fourth resistance element connected between the first node and the ground, the first coupling circuit includes a fifth resistance element configured to couple the output terminal of the operational amplifier of the first second-order integrator to the second node in the second second-order integrator with the polarity mutually inverted, and a sixth resistance element configured to couple the output terminal of the operational amplifier of the second second-order integrator to the second node in the first second-order integrator with no polarity inversion involved, and the second coupling circuit includes a seventh resistance element configured to couple the inverted input terminal of the operational amplifier of the second second-order integrator to the second node in the first second-order integrator with the polarity mutually inverted, and an eighth resistance element configured to couple the inverted input terminal of the operational amplifier of the first second-order integrator to the second node in the second second-order integrator with no polarity inversion involved.