Countering the effects of frequency pulling in the signal of a local oscillator by phase shifting its signal in proportion to the amount of frequency pulling.

摘要

A signal conversion apparatus includes a local oscillator for locally generating a signal having a frequency, a phase shifter for shifting the phase of the locally generated signal output from the local oscillator by an amount determined based on a relationship between the amount of phase shift and the amount of frequency pulling, and a converter for converting an input signal by using the phase-shifted locally generated signal output from the phase shifter. The phase shifter varies impedance between the local oscillator and the converter so that the oscillating frequency of the locally generated signal output from the local oscillator remains unchanged.