壓電元件的應用研究主要是為了解決壓電轉能器在超音波量測技術上，因為壓電特性所造成起振延遲誤差。本研究提出一種新型的超音波轉能器驅動波形，以自我干擾式波形來克服起振延遲影響並準確量測超音波的飛行時間(TOF, time-of-flight)，並可用來做為準確的超音波溫度及距離量測。
第一個研究主要提出以超音波飛越時間技術取得聲音速度量測精確的溫度。此系統以新型的驅動波形結合了振幅調變和相位調變技術(APESW, AM and PM envelope square waveform)，並以此讓接收波形產生自我干擾和相位反轉現象。此自我干擾和相位反轉現象在超音波接收波形產生的明顯的標記，可用來準確判斷超音波飛行時間及量測空氣溫度。以本研究所建立的超音波溫度量測系統，結合濕度補償演算法，準確度的不確定性可低於0.39 ℃；此外解析度可達所採用40 kHz頻率波的0.1 %波長。
第二個研究主要以超音波傳感器自我溫度補償來量測精確的距離。此系統可隨空氣中環境的平均溫度做自我溫度補償(STC, self-temperature-compensation)，而不僅僅依據單一點的溫度。此系統採用了兩種完全相同的量測硬體配置，並使用APESW超音波驅動波形。第一個硬體配置量測了聲速（也包含了環境平均溫度的資訊）作為第二個距離量測配置的溫度補償資料。在沒有使用溫度感測器之下，以本研究所建立的超音波STC距離量測系統可以精確地量測到距離，在50到500毫米的距離量測，實驗標準差是0.21毫米;此外，此系統的溫度不確定性產生的影響標準偏差是0.093毫米， 而溫度傳感器系統的不確定性的影響產生了標準偏差0.68毫米。因此，以本研究所產生的新型特殊超音波驅動法可用來解決因壓電特性所造成的延遲誤差，並具備了高準確度及高解析度的特性。此外本研究所提出的演算法可輕易在其他微處理器上實現。其他的優點還有低成本、抗雜訊及容易實現等。

This dissertation proposes a time-of-flight (TOF) measurement by employing a piezoelectric and converse piezoelectric produced self-interference ultrasonic wave. When using TOF techniques for ultrasonic temperature and distance measurement, the system error is primarily due to the inertia delay phenomenon of machine vibration. This dissertation proposes a novel driving algorithm for an ultrasonic transmitter.
The first study proposes an accurate temperature measurement is derived from the measurement of sound velocity by using an ultrasonic time-of-flight (TOF) technique. The study proposes a novel algorithm which combines both amplitude modulation (AM) and phase modulation (PM) for the TOF measurement. The proposed system can reduce error caused by inertia delay when using the AM and PM envelope square waveform (APESW). The APESW ultrasonic driving waveform causes an envelope zero and phase inversion phenomenon in the relative waveform of the receiver. To accurately achieve a TOF measurement, a phase inversion phenomenon was used to sufficiently identify the measurement pulse in the received waveforms. Additionally, a counter clock technique was combined to compute the phase shifts of the last incomplete cycle for TOF. The presented system can obtain 0.1 % TOF resolution for the period corresponding to the 40 kHz frequency ultrasonic wave. Consequently, with the integration of a humidity compensation algorithm, a highly accurate and high resolution temperature measurement can be achieved using the accurate TOF measurement. Experimental results indicate that the combined standard uncertainty of the temperature measurement is approximately 0.39 ℃.
The second study proposes an accurate distance measurement system which has self-temperature-compensation (STC) with the environmental average temperature in space, rather than a single point temperature. The proposed system adopts two identical measurement hardware sets using the APESW ultrasonic driving waveform. The first set measures the sound velocity (the environmental average temperature information is also involved) as the result of the temperature compensation data for the second distance measuring set. Without using a temperature sensor, experimental results indicate that the proposed STC distance measurement system can accurately measure the distance. The experimental standard deviation of the linearity with respect to the distance is found to be 0.21 mm at a range of 50 to 500 mm. Moreover, the proposed system’s temperature uncertainty effect produced a standard deviation of 0.093 mm, while the temperature sensor system’s uncertainty effect produced a standard deviation of 0.68 mm. In addition, the proposed driving algorithm benefits from noise resistance and ease of implementation. The algorithm is simple and can be easily adapted for other micro-processors. The main advantages of this AM and PM envelope square waveform (APESW) system are high resolution measurement, low cost, narrow bandwidth requirement, and ease of implementation.

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