| 摘要 |
PROBLEM TO BE SOLVED: To solve problems of the conventional digital wireless unit that has increased number of components and required complicated level control by a control section in providing an attenuator to a pre-stage of an amplifier section in order to prevent a signal from being saturated in the amplifier section for amplifying the signal level when received signal power has a high level. SOLUTION: A switching path of an antenna switch 1 is usually connected to a receiver side at reception, but when a high level input is received, the switch 1 is switched to a transmitter side and a switch 13 switches a path of giving an output signal from a terminal (f) of a directional coupler 10 to a reception input section. Through the configuration above, even when the digital wireless unit receives a high level signal, since the attenuated power is given to the receiver side, the receiver side receives a signal with a lower level than that at the antenna terminal and can avoid saturation of the amplifier section to eliminate the need for an attenuator.
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