| 摘要 |
PROBLEM TO BE SOLVED: To provide an ultrasonic measurement circuit and a liquid-level detection system using it, allowing reduction of the influence of noise when detecting a reflected wave reflected by an object to be detected, and to accurately measure the position of the object to be detected. SOLUTION: The ultrasonic measurement circuit emits ultrasonic waves toward the object to be detected from an ultrasonic sensor 3 to measure the position of the object to be detected by detecting the reflected wave reflected by the object to be detected. The circuit comprises a transmitting circuit 110 for providing the ultrasonic sensor 3 with a drive signal for emitting ultrasonic waves and a receiving circuit 120 for detecting the reflected wave signal, corresponding to the reflected wave out of reception signals received by the ultrasonic sensor 3. The receiving circuit 120 has an adjustment means 124 for changing the signal level of the reception signal or the decision level of the received signal for a period shorter than the period between the emission of the drive signal and the reception of the reflected wave. COPYRIGHT: (C)2006,JPO&NCIPI |
