| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a small loss high-frequency circuit which is easily reduced in size and simplified in circuit constitution. <P>SOLUTION: The circuit has a transmission/reception bidirectional antenna 10, a modulation circuit 11, a SPST switch circuit 12, and a demodulation circuit 13 each disposed sequentially. In receiving a signal, the SPST switch circuit 12 is switched on, and the demodulation circuit 13 extracts a signal wave from the signal received through an antenna 10, before outputting to a control circuit 3 therefrom. At transmission of the signal, the SPST switch circuit 12 is switched off, and the demodulation circuit 13 outputs transmission data which is received from the control circuit 3 ad superimposed on a carrier wave to the antenna 10. Only a single antenna is needed. The modulation circuit 11, the SPST switch circuit 12, and the demodulation circuit 13 can be constituted with a simple circuit, thereby can be easily reduced in size. The modulation circuit 11 can be constituted easily neglible in receiving the signal, and the demodulation circuit 13 can be constituted neglible in transmitting the signal by an off operation of the SPST switching circuit 12, thereby a low-loss circuit can be obtained. <P>COPYRIGHT: (C)2004,JPO</p> |
