本論文以2.4 GHz ISM頻帶作為操作頻率，運用鎖頻迴路機制(Frequency-locked loop, FLL)並結合主動式濾波器之生理感測器，提出相位正交追蹤技術以避免偵測零點(null point)的產生。雷達所偵測到之生理訊號為胸腔和心跳的微小擺幅所組成的相位變化，隨著量測距離的增加，其被雷達所偵測到之訊號強度亦會有所減少，此時若雷達無法提供穩定的本地振盪訊號(local oscillator, LO)，或是能將所偵測的相位變化訊號放大，則生理訊號將有可能在接收訊號時被本地振盪源自身的相位雜訊所覆蓋而無法被偵測。鎖頻迴路能有效地在迴路頻寬內，將壓控振盪器(voltage-controlled oscillator, VCO)之相位雜訊抑制，使得振盪源本身輸出的頻率更加穩定，減少自身的相位雜訊。本論文將此特性運用在生理雷達系統上，不但可以降低系統雜訊還可以放大所偵測之生理訊號。這可提升雷達輸出訊號的訊號雜訊比(signal-to-noise ratio, SNR)，因而增加生理訊號感測的靈敏度。實驗結果顯示，隨著目標物與生理感測器之間的距離從1 m增加至2 m，雷達系統之相位雜訊也在頻率偏移10 kHz下改善了約10 dB。而訊號雜訊比也有顯著改善。在待測物距雷達4 m之條件下，鎖頻迴路生理雷達之訊號雜訊比較傳統連續波(continuous wave, CW)雷達之訊號雜訊比多約18.3 dB。本論文利用鎖頻迴路生理雷達之相位正交追蹤技術，分別針對人體在隨機擺動、快速走動等狀況下量測生理訊號，量測結果顯示鎖頻迴路生理雷達皆能夠正確量測出待測人體之生理訊號，且與生理偵測綁帶之偵測結果相近。

This thesis presents a 2.4 GHz ISM band vital-sign radar and exploits the frequency-locked loop (FLL) architecture with an active loop filter. To overcome the issue of null point, this work uses a novel quadrature-tracking technique. The vital sign detected by the radar is the phase variation due to tiny vibration of chest and heartbeat. As the range of detection increases, the strength of the signal that is received by the radar decreases. If the radar is not able to support more stable LO signal or enhance the strength of the received signal, the vital sign will be overwhelmed by the phase noise of the oscillator and can not be detected. The FLL can reduce the phase noise of voltage-controlled oscillator (VCO) in the loop bandwidth, it will make the VCO output frequency more stable with less phase noise.
This work takes advantage of the above features in the proposed radar system to amplify the detected vital sign and suppress the phase noise of the system. The output SNR will also be improved to increase the sensitivity and efficiency of the vital sign detection. The experimental results show that the phase noise of the radar system improves by about 10 dB at 10 kHz offset frequency when the distance between the target and radar increases to 2 m. Experimental results also demonstrate that the SNR of the wireless-FLL-based sensor is around 18.3 dB more than that of the conventional CW radar at a detection range of 4 m. This work also performs the vital sign detection when the human body is in random motion and running at the treadmill. The experimental results show that the detected vital sign is accurate when compared to the data of reference device.

論文審定書 i
論文公開授權書 ii
誌謝 iii
摘要 iv
Abstract v
目錄 vi
圖次 viii
表次 xi
第1章 緒論 1
1-1研究背景與動機 1
1-2 生理感測器的發展沿革 3
1-3章節規劃 8
第2章 運用鎖頻迴路之生理感測雷達原理 9
2-1 鎖頻迴路 9
2-2 運用鎖頻迴路之生理感測雷達 11
2-2-1 時域模型分析 12
2-2-2 頻域模型分析 14
2-2-3 訊號雜訊比分析 17
2-3 運用鎖頻迴路之生理感測雷達模擬 20
第3章 運用鎖頻迴路之生理雷達實驗 23
3-1 運用鎖頻迴路之生理感測雷達 23
3-2 相位雜訊及暫態響應實驗 26
3-3 相位追蹤實驗 28
3-4運用鎖頻迴路之生理雷達性能量測 29
3-4-1 運用致動器之量測實驗 29
3-4-2 人體生理訊號量測實驗 31
第4章 結論與未來展望 46
參考文獻 47

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