QUADRATURE MODULATOR

摘要

PROBLEM TO BE SOLVED: To provide a quadrature modulator which accurately detects an operation frequency fsymincluded in a quadrature modulation signal to be transmitted so as to suppress a carrier leak component. SOLUTION: According to the present invention, the quadrature modulator which outputs a base-band digital signal as a quadrature modulation signal is characterized in that a sine wave to be input to a demodulating circuit 21 for detection is generated by generating the sum frequency of a predetermined frequency fc of a carrier and the operation frequency fsymof a base-band digital output circuit 12 by a second PLL 33 from a local oscillation wave generated by a local oscillator 31 common to the carrier of the base band. COPYRIGHT: (C)2008,JPO&INPIT