| 摘要 |
PURPOSE:To enable increase in the medium-and short-range signal proving rate while searching and distance measurement are done in the long range by providing a plurality of signal processing systems generating a plurality of modulation frequencies corresponding to a plurality of carrier frequencies. CONSTITUTION:Signals different in the frequency from a transmit signal generation circuit 11 is selected with a transmit signal switching circuit 13 and ultrsonic waves with a plurality of frequencies are transmitted from an electroacoustic tranducer 4. Reflected ultrasonic waves are received, processed with multiple systems of modulation circuit 7, a signal processing circuit 8 and the like to which modulation signals are applied corresponding to carrier frequencies through a local signal generation circuit 12 and a local signal switch 14 and then, signal probing information is written into areas 9a and 9c of an indication memory 9 through a memory switch 15 for each frequency. This enables increase in the medium-and short-range signal proving rate while searchig and distance measurement are done for the long range thereby preventing the missing of a target regardless of a reflecting body high in the moving speed, a reflecting body suddenly detected in the short range and the like. |
