許多神經疾病是由於腦中神經細胞產生障礙或退化，導致神經功能運作不正常而影響病患行動或言語。疾病無法有效地以藥物治療，取而代之的是以電訊號來刺激疾病相關腦區。
由於要精準地給予相關腦區進行適量的電訊號刺激，神經電極的阻抗頻譜圖是必須要知道的，本論文因應本實驗室所做之DBS神經電極大小進而估算出預計量測之阻抗範圍，進而進行後續的電路設計。
在傳統的生物電極阻抗量測中，電流驅動量測法是主要的方式，原因為一般的待測物以電阻性居多，而且電流驅動量測法的方式是以電阻取代電容可以相對地減少其面積上的消耗。
本論文使用一個以電壓輸入量測阻抗的方式，原因為所需量測電極之等效電阻過大的關係，無法輕易的以電流打入待測物，。
本論文之電路包括了以下幾個部分:由數位類比轉換器組成之訊號產生器、低聲噪放大器、數位回授控制器、連續近似類比數位轉換器以及輸入漏電補償電路，設計上可量測範圍為25f法拉至1.5n法拉，利用數位類比轉換器組成之訊號產生器製作一正弦波打入待測物後觀察低聲噪放大器之輸出端放大倍率來得出待測物之阻抗，若超出一定量值後可利用數位回授控制器來更改低聲噪放大器之回授電容，若在可量測範圍內，則會透過數位類比轉換器轉成數位訊號輸出。

Many neurological diseases are caused by malfunction or degeneration of Neuro cells in the brain, resulting in abnormal functioning of Neuro function and affecting patients' actions or speech. Diseases cannot be effectively treated with drugs. Instead, electrical signals are used to stimulate disease-related brain regions.
Due to the precise amount of electrical signal stimulation to the relevant brain area, the impedance spectrum of the Neuro electrode must be known. This paper estimates the estimated impedance range according to the size of the DBS Neuro electrode made by this laboratory. Then proceed to follow-up circuit design.
In the traditional bioelectrode impedance measurement, the current-driven measurement method is the main method, because the general test object is mostly resistive, and the method of the current-driven measurement method is that the resistance is replaced by the capacitor to relatively reduce its Area consumption.
This paper uses a voltage-driven method to measure impedance. The reason is that the required measurement electrodes are mainly capacitive, which cannot easily be driven into the object under test with traditional current. It will decrease as the frequency increases, so a voltage measurement method is needed to provide a more accurate value.
The circuit of this paper includes the following parts: a signal generator composed of a digital analog converter, a low-noise amplifier, a digital feedback controller, a SAR analog digital converter, and an input leakage compensation circuit, which can be measured in design The range is 25f farad to 1.5n farad. Use a signal generator composed of a digital analog converter to make a sine wave into the object to be measured. Observe the magnification of the output of the low-noise amplifier to obtain the impedance of the object to be tested. After the measurement, the digital feedback controller can be used to change the feedback capacitance of the low-noise amplifier. If it is within the measurable range, it will be converted into a digital signal output through a digital analog converter.

目錄
致謝 III
摘要 V
Abstract VI
圖目錄 X
表目錄 XIV
第1章 緒論 1
1-1 研究動機 2
1-2 章節介紹 2
第2章 電極特性與阻抗量測機制 3
2-1 電解質-電極介面的阻抗模型 3
2-2 電流模式輸入量測法 7
2-3 電壓模式輸入量測法 10
2-4系統架構評估與選擇 11
第3章 前端架構與設計 14
3-1 待測電極考量 14
3-2 低聲噪放大器設計 14
3-2-1 電路分析與計算 14
3-2-2 調變頻率之選取 23
3-3 模型介紹與模擬結果 24
第4章 ADC與DAC設計 47
4-1 類比數位轉換器設計 47
4-1-1 類比數位轉換器架構選擇 48
4-1-2 取樣電路設計 49
4-1-3 比較器設計 50
4-1-4 電容式數位類比器考量 51
4-1-5 模擬及模型驗證 53
4-2 數位類比轉換器設計 57
第5章 量測結果與分析 61
5-1 晶片佈局圖 61
5-2 量測平台 65
5-3 量測結果與問題 67
5-3-1 OPAMP量測結果 67
5-3-2 量測問題與模擬驗證 74
第6章 結論與未來工作 84
參考文獻 85

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