PURPOSE: To considerably reduce the production of a frequency component due to even number order harmonics by controlling the nonlinear resistor of a mixer diode so as to correct the unbalance of a single mixer circuit with a control section thereby providing an ideal single balance mixer state.
CONSTITUTION: A control section 14 receives a ramp signal corresponding to an oscillated frequency fosc of an oscillator 15 and reads a correction value corresponding thereto is read from a correction memory 15 and fed to a D/A converter 12. The D/A converter 12 receives correction data from the control section 14 and converts the data into an analog voltage signal, which is fed to a resistor 16. A bias current is supplied through the resistor 16 to bias either of diodes 81, 82 in a forward/backward direction. Furthermore, the resistor 16 has a high resistance so as not to provide any effect onto a high frequency circuit. Thus, a nonlinear resistor Rj of the mixer diodes 81, 82 is controlled for each unit frequency to correct the unbalance of a single mixer circuit 50.
SAKUMA HIROSHI
MIYAUCHI YASUSHI
