Noise cancellation circuit and amplifier with noise cancellation circuit

Abstract

A noise cancellation circuit, which reduces noise in an output signal of an amplifier having an input resistance, a feedback resistance, and an operational amplifier, has: a first mixer circuit, which input an input signal across a first input terminal and a second input terminal of the operational amplifier, and performs frequency conversion of the input signal according to a first frequency signal; a noise cancellation amplifier, which amplifies an output signal of the first mixer circuit; a second mixer circuit, which performs frequency conversion of an output signal of the noise cancellation amplifier according to the first frequency signal; and a signal supply circuit, which supplies an output signal of the second mixer circuit to the first input terminal of the operational amplifier via an output resistance.

Dependencies are inferred from the claim text.