| 摘要 |
PURPOSE:To prevent the deterioration in the line quality at a fault of a switch control circuit by turning off any of high frequency switches when a transmission output exceeds a setting value. CONSTITUTION:In removing a high frequency switch control circuit 2 at a fault or a mis-operation, the high frequency switches 3a, 3b are turned on, each transmission signal from active/standby transmitters 1a/1b is synthesized and the level is increased. The level increase is detected by a power detector 4a, an initiator 5 senses the rise of an output power by the DC voltage of the detection output and when the power exceeds a setting value, a transistor 6 is turned on. Thus, a relay 7 is activated and a voltage V is supplied and the standby high frequency switch 3b is turned off. Then the transmission is executed from the active transmitter 1a only.
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