Mixer having filtering module to filter out low-frequency components to minimize noise

Abstract

A mixer for down-converting an input signal to an output signal is disclosed. The mixer includes an amplifying circuit and a down-converting circuit. The amplifying circuit is utilized for amplifying the input signal to generate an amplified signal. The down-converting circuit includes a filtering module, a loading module, and a down-converting module. The filtering module is coupled to the amplifying circuit, and is utilized for filtering low-frequency components in the amplified signal. The loading module is coupled to the amplifying circuit and a predetermined voltage level, and is utilized for providing a DC bias voltage to the amplifying circuit. The down-converting module is coupled to the filtering module and the predetermined voltage level, and is utilized for generating the output signal according to a local oscillating signal.