| 摘要 |
PROBLEM TO BE SOLVED: To provide a general-purpose apparatus for detecting an object, which can reduce errors caused by mixing of undesired waves or the influence of multipath phasing and the like. SOLUTION: In the apparatus, a VCO 101 varying its oscillation frequency in response to input voltage is disposed as a source of signal oscillation in a transmitting system circuit 10, and a voltage signal is generated by a control signal generating circuit 30 in order to bring the VCO 101 to oscillate a high frequency signal having a frequency at which received detection voltage represents the maximum level in its stationary mode, and input to the VCO 101. A determination circuit 40 determines whether or not the object enters a radio transmission channel between a transmitting antenna At and a receiving antenna Ar, by sensing variations from the stationary mode in the received detection voltage of a receiving system circuit 20. COPYRIGHT: (C)2005,JPO&NCIPI |
