| 摘要 |
PROBLEM TO BE SOLVED: To provide a radio receiving circuit which satisfies reception sensitivity and a jamming-proof property without using an RF filter and is inexpensive and small, and to provide a radio apparatus provided with the radio receiving circuit. SOLUTION: This radio receiving circuit 14 in a radio apparatus 1 includes a first RF amplifier circuit 30 having a low noise characteristic and a second RF amplifier circuit 32 having an intermodulation distortion-resistant characteristic. The signal level of a reception signal received by an antenna 10 is detected by an RSSI circuit included in an FSK demodulation circuit 42. When the level of the reception signal is not higher than a prescribed level, selection switches 34 and 36 select the first RF amplifier circuit 30, and when the level of the reception signal is higher than the prescribed level, the selection switches 34 and 36 select the second RF amplifier circuit 32. COPYRIGHT: (C)2005,JPO&NCIPI
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