| 摘要 |
PURPOSE:To ensure the determination of the position of a reflecting body with a good SN ratio without the effect of ultrasonic wave echoes caused by grating lobes, by detecting the presence or absence of the ultrasonic wave echoes at a time point, where the echo will be obtained from a focal point, and the time points before and after said time point. CONSTITUTION:A time gate circuit 36 receives a time gate starting signal and a time gate width signal from an ultrasonic wave beam control device 32. In the circuit 36, a necessary part is extracted from a received ultrasonic wave signal based on a time gate. The extracted ultrasonic wave signal part is coded into a signal comprising ''0'' and ''1'' by a waveform shaping device in the circuit 36. Then specified logic operation is performed. The result of the operation is sent to a signal processing device 37. The signal processing device 37 obtains the position of a reflecting body by using ultrasonic wave beam control signals such as an incident angle of an ultrasonic wave beam, the position of a focal point, and the like in a body to be checked from the ultrasonic wave beam control device 32, the received ultrasonic wave signal from a delay circuit 34, and the reflected-wave judging signal at the main lobe of the ultrasonic wave beam from the time gate circuit 36. The data such as the position of the reflecting body, an ultrasonic wave beam scanning signal, and the like are sent to a display device 38.
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