The Study of a High Precision Ultrasoni Sound Veloity Measurement System
碩士 === 義守大學 === 電機工程研究所 === 85 === The sound velocity is a very important parameter for many ultrasonic based measurements. Most of the airborne type ultrasonic measurement systems are assume the sound velocity to be a constant (348∼360m/s) when operate. Some of them can measure the room temp...
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| Format: | Others |
| Language: | zh-TW |
| Published: |
1997
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| Online Access: | http://ndltd.ncl.edu.tw/handle/04795528238587288711 |
| Summary: | 碩士 === 義守大學 === 電機工程研究所 === 85 ===
The sound velocity is a very important parameter for many ultrasonic based measurements. Most of the airborne type ultrasonic measurement systems are assume the sound velocity to be a constant (348∼360m/s) when operate. Some of them can measure the room temperature and use a look up table to estimate the sound velocity. However the real velocity value at the measurement environment is still unknown. This will influence the measurement result of the ultrasonic system. In this article an ingenious method to measure sound velocity in air has been developed. A pair of low cost 40-KHz ultrasonic transducers is used to transmit and receive ultrasonic signals face by face. A single-chip microcomputer-based phase detector was designed to record the phase difference between transmitting and received ultrasonic signals. After a calculation procedure, the sound velocity can be given from the phase difference value. The main advantages of this system are: high precision, low cost, and easy to install.
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