| 摘要 |
PROBLEM TO BE SOLVED: To make a phase adjustment circuit of a directional coupler stable against temperature changes. SOLUTION: An oscillated frequency is changed by changing a bias voltage of a varactor diode 1. An F-V conversion circuit 4 converts the oscillated frequency of the oscillator 3 into a voltage, which is compared with a reference voltage at comparator circuit 5, its output controls a voltage controlled source 6, and its output is fed back to a bias power supply of the varactor diode 1. The bias voltage of the varactor diode 1 is to be a voltage to apply temperature compensation to the varactor diode 1. The temperature compensation bias voltage of the varactor diode 1 is the same as varactor diodes 7, 8, then the temperature compensation bias voltage is fed to the varactor diodes 7, 8 via a voltage mixer 15, then the phase characteristic of the directional coupler 11 is sufficiently made stable. |
