PURPOSE: To correctly monitor an antenna and an electricity feeding system for antenna by preventing the erroneous detection due to the turning around from the antenna of other system.
CONSTITUTION: As for a monitoring device 100, a direction type joint device 12 detects the intensity Et of the transmission wave and the intensity Er of the reflection wave by the joining with a transmission line for an antenna 13 from a combiner 11. The wave detection circuits 14 and 15 outputs the wave detection signals Vt and Vr corresponding to each intensity. The voltage signal Vo corresponding to the reflection coefficient is obtained from the ratio of the wave detection signal Vr of the reflection wave for the wave detection signal Vt of the transmission wave. When the reflection coefficient exceeds a certain value, a comparator 19 outputs the level of a logic 1, and when the wave detection signal Vt of the transmission wave exceeds a certain value, a comparator 21 outputs the level of the logic 1. The logic sum of the comparators 19 and 21 is obtained by an AND circuit 23.
WADA SHUICHI
YAMASHITA SADAO
MASAFUJI YOSHITO
