傳統物質感測系統需要使用昂貴且笨重的儀器設備，無法整合運用於一般之消費性電子產品中，並且需要較長之檢測時間，而不便於日常生活中之使用。由於近年來積體電路之迅速發展，設計並實現可攜式、即時性、與低功耗之物質感測系統成為可能。本論文發展非侵入式物質感測系統之介面積體電路。利用待測物質組成一振盪器，透過檢測振盪訊號之頻率及振幅大小來分辨不同物質之介電係數。
本研究所提出的介面電路架構不使用鎖相迴路及獨立的類比數位轉換器來檢測頻率，而是將之振盪器產生的振盪訊號經適當的除頻後，所產生的頻率訊號來控制一個參考電流源對一個積分器充電，利用計數器來檢測振盪器頻率。讀取頻率的解析度將可隨積分時間的增加而改善。另外使用負迴授控制，利用控制偏壓電流的大小來使振盪器的振盪訊號振幅固定，利用所提供之電流大小做為物質損耗的檢出讀值。
本論文所提之感測介面電路使用台積電0.18um製程完成一測試雛形晶片以進行可攜式感測系統驗証。本研究除完成基本電路區塊之定性與定量測試、並驗証感測系統訊號雜訊比隨積分時間增加而增加之理論推導，實驗結果並顯示此系統可輕易地分辨出不同濃度之甲醇、乙醇與水。因此本論文之研究成果為未來發展可應用於可攜式智慧型裝置之低功耗非侵入式物質感測系統奠定重要基石。

Traditional material sensing systems require expensive and bulky equipment with long detection time and can not be integrated in consumer electronics, limiting their use in our daily lives. Thanks to the rapid developments in integrated circuits, it has become possible to realize a portable real-time material sensing system with low power consumption. In this thesis, a non-invasive material system is proposed and developed. The material under test forms a resonantor and its dielectric constant can be detected from the oscllation frequency and amplitude.
Instead of using a phase-locked loop with an analog-to-digital converter, the interface circuit proposed in this research employs a switched constant current source, an integrator, and counters for resonant frequency detection. Frequency resolution will be improved with increased integration time. In addition, by using negative feedback, the material loss can be detected by reading out the amount of bias current that is supplied to the resonantor to keep the oscillation amplitude constant.
The proposed integrated sensing interface circuits have been designed and fabricated in a TSMC 0.18um process. This prototype chip has been tested to verify the feasibility of a portable non-invasive sensing system. All the basic circuit blocks in this system have been tested. The testing results also verify that the signal to noise ratio improves proportionally to the integration time as derived theoretically. Experimental results show that water, methanol, and ethanol with different concentrations can be distinguished in this system. Therefore, the achievements of this thesis have laid down fundamental milestones for future development of portable non-invasive material sensing system.

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