PURPOSE: To attain small in size, light weight and low power consumption by using a microwave oscillator for a local oscillator, and providing a crystal oscillator outputting an oscillating frequency equal to a frequency at equal intervals of an input signal, a transmitting means transmitting a signal of a (m) times frequency, a means obtaining a difference between local oscillating frequencies and each phase locked loop comprising a phase comparator.
CONSTITUTION: The crystal oscilltor 11 is a crystal oscillator having a highly stable frequency at equal intervals of the input signal. A harmonic generator 12 generates a frequency being an integral multiple of an output frequency of the oscillator 11. A frequency corresponding to adjacent frequency difference of each local oscillator 7 is selected respectively by each BPF of the output frequency and inputted to a phase detector 15. Local oscillating frequencies fL2, fL3 are inputted to a hybrid 8 and fL2-fL1 and fL3-fL1 are inputted to a phase detector 15. The phase difference between the said frequency and the output of the BPF13 is obtained respectively and detected, VCO7-2, 7-3 are controlled respectively via a loop filter 14 so as to eliminate the phase difference. Thus, the frequency difference between the local oscillators is suppressed by the characteristic of the crystal oscillator 11 and the difference in the intermediate frequency is eliminated. Further, since only one crystal oscillator is enough for the circuit, small in size, light weight and low power consumption are attained.
TAKANO TAKESHI
SHIMA TAKAO
