Frequency mixer

Abstract

A frequency mixer is provided with a mixer circuit having an input cell that amplifies an input signal and a switching cell that mixes the amplified input signal with a switching signal and outputs a multiplied signal, and a DC offset compensator that detects the input level of the input signal and outputs a compensation signal based on that detection signal, and compensates the DC offset included in the output signal of the mixer circuit by supplying the compensation signal to the mixer circuit. The DC offset compensator is provided with a detector of the input signal level that is input to the mixer circuit, a limiter circuit that attaches a limit to the output of the detector, and a controller that generates a signal that compensates the DC offset included in the mixer output signal based on the limited detector output. When a high-level signal is input, DC offset due to second order nonlinear distortion is compensated while preventing a deterioration in the properties of the mixer circuit due to the compensation signal becoming too large.

Dependencies are inferred from the claim text.