Frequency converter, orthogonal demodulator and orthogonal modulator

摘要

A frequency converter comprising a variable gain amplifier which amplifies the local oscillation signal according to a gain control signal and outputs an amplified local signal, an even harmonic mixer which is supplied with an input signal and an amplified local oscillation signal and outputs an output signal whose frequency is a sum of a first frequency of the input signal and a second frequency of two or more even numbered times a frequency of the amplified local oscillation signal, an amplitude detector which is supplied with the amplified local oscillation signal and outputs a direct current signal having an amplitude corresponding to an amplitude of the amplified local oscillation signal, and a comparator which compares the direct current signal of the amplitude detector with the reference direct current signal to generate an output signal as the gain control signal.