APPARATUS FOR GENERATING AN ORTHOGONAL PHASE SIGNAL USING COMPLEX COEFFICIENT FILTER

摘要

A quadrature phase oscillator using a complex coefficient filter is provided to simply and easily implement the quadrature phase oscillator by not mounting an R-C polyphase filter or Master-Slave flip-flop on a radio frequency transceiver IC chip. A voltage controlled oscillator(20) provides an oscillating frequency for modulation of a transmission/reception signal according to an applied voltage. A filter(22) receives the oscillating frequency from the voltage controlled oscillator as an input, passes one of a negative frequency component of the input oscillating frequency and a positive frequency component of the input oscillating frequency, attenuates the other frequency component, generates an I signal that is in phase with the input oscillating frequency and a Q signal having a phase difference of 90 degrees with the input oscillating frequency for the passed frequency component, and outputs the I signal and the Q signal.