| 摘要 |
PURPOSE:To improve the economy and the reliability of the system by providing two systems of common amplifier sections converting a reception signal branched into a signal having a different level difference into the 1st intermediate frequency signal by a directional coupler and selecting the system by a switch. CONSTITUTION:A reception signal inputted to a band stop filter 7 from a circulator 6 of a device reception section is branched into two by a directional coupler 101 and inputted respectively to common amplifier sections A, B. The signal is converted into a 1st intermediate frequency signal by 1st mixer 103 in the section A and outputted to a switch 107. Similarly, the signal is converted into the 1st intermediate frequency signal by a 1st mixer 113 in the section B and outputted to a switch 107. The switch 107 selects either signal of the amplifiers A, B and gives the result to a 1/n distribution circuit 12. The input electric field of the signal is detected by a signal detection circuit 108, a switch control circuit 109 switches the switch 107 depending on the detection value to select either signal of the amplifiers A, B. The two systems of common amplifier sections are used as standby/active sections, then the reliability and economy are improved.
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