| 摘要 |
PURPOSE:To make it possible to perform the optimum measurement meeting the requirement by measuring the propagating time of two ultrasonic waves in liquid. CONSTITUTION:In a measuring apparatus 10, a piezoelectric transducer 18 is provided between the bottom surface 14 of a container 12 for storing liquid and a liquid surface 16. The transducer 18 receives an ultrasonic wave 28 which is reflected from the bottom surface 14 and reaches the transducer 18 and an ultrasonic wave 30 which is reflected from the liquid surface 16 and reaches the transducer 18. The transducer 18 generates the first received signal in response to the ultrasonic wave 28 and generates the second received signal in response to the ultrasonic wave 30. The first and second propagating time of the ultrasonic waves 28 and 30 in the liquid are computed in correspondence with the first and second received signals. The ratio between the second propagating time and the first propagating time is obtained. Thus the height of the liquid surface can be obtained by a specified expression. |
