| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a radio communication system with a signal measurement circuit for carrying out reception operation control and band use state discrimination. <P>SOLUTION: The radio communication system includes the signal measurement circuit for detecting the strength of received first and second signals with a first band or a second band narrower than the first band. At an initial setting including time of power application, a first selection circuit selects the first signal with the first band or below, and a second selection circuit selects the second signal with the second band or below. When no first and second signals exist, a first mode is selected wherein the signal is transmitted/received with the first band or below. When the first signal exists and no second signal exists, a second mode is selected wherein the signal is transmitted/received with the second band or below. When both the first and second signals exist, a third mode is selected wherein the signal transmission/reception is stopped. In the signal transmission/reception, the strength of the first and second signals is detected corresponding to the first or second mode to form a gain control signal of first and second variable gain amplifier circuits. <P>COPYRIGHT: (C)2008,JPO&INPIT |
