| 摘要 |
<P>PROBLEM TO BE SOLVED: To keep the cost of manufacturing low while maintaining the low noise property and the maximum reception sensitivity with a simple configuration. <P>SOLUTION: A reception antenna receives a reception wave reflected from a target object and outputs a high-frequency signal when a transmission wave is transmitted from a transmission antenna to the target object. A limiter circuit suppresses the high-frequency signal outputted from the reception antenna on the basis of a predetermined allowable power level and outputs it. A low-noise amplifier amplifies and outputs the inputted high-frequency signal. A detection circuit branches the high-frequency signal outputted from the low-noise amplifier, determines a saturation state of the low-noise amplifier on the basis of one of the branched high-frequency signals, and outputs a control signal related to a path of the high-frequency signal on the basis of the saturation state. A high-frequency switch switches the path of the high-frequency signal outputted from the limiter circuit to a path including the low-noise amplifier on the basis of the control signal outputted from the detection circuit or transmission and reception timings of the transmission wave and the reception wave. <P>COPYRIGHT: (C)2013,JPO&INPIT |
