Patent ID: 6973136

Claim:
Radio communications apparatus comprising: a quadrature modulator for making the transition of the phase of a modulated wave via a in-phase component and a quadrature component; a first voltage-controlled oscillator for outputting a first transmission signal; a second voltage-controlled oscillator; a first mixer for frequency-converting the first transmission signal based on the output signal of the second voltage-controlled oscillator; a phase comparator for comparing the phase of the output signal of the quadrature modulator with the phase of the output signal of the first mixer; a low-pass filter for filtering the component below a predetermined frequency of the output signal of the phase comparator and supplying the resulting signal to the frequency control terminal of the first voltage-controlled oscillator; a first band-pass filter for outputting a signal obtained by filtering the component in a predetermined frequency band of the output signal of the quadrature modulator as a second transmission signal; a first transmitter for amplifying the first transmission signal and transmitting the resulting signal via a first antenna; and a second transmitter for amplifying the second transmission signal and transmitting the resulting signal via a second antenna.