已有研究指出，帕金森氏患者的腦波在其特定頻帶上(LFP、spikes)會有異於常人的訊號，藉由偵測此一異樣訊號並告訴內部刺激器做適當的電流刺激，將可抑制不正常腦波發生，對患者做進一步的診療。本論文研究的宗旨及為發展出一套高效能的前端架構，期待能整合於生醫訊號擷取系統。
在前端感測器中，為了擷取極低頻(~0.1Hz)的神經訊號，電路前端所加的DC block電容往往需要達到nano-farad等級，造成植入面積過大的難題，本論文採用了漏電流互補式的pseudo resistor架構，形成極高阻值的偽電阻，以60pF的輸入電容，達到0.1Hz的高通轉角頻率，克服大面積電容的問題。
在活體生物量測中，往往會有運動雜訊的干擾以及刺激器高壓破壞的問題，前者會造成感測訊號飽和，後者則會使輸入閘極被打穿，為了克服此問題，我們發展出了新型的感測器與消除器，能在200μs的時間把運動雜訊消除掉，重新讀出微小神經訊號，此外，運動雜訊消除器搭配PMOS diode的運作，提供了刺激器雙重的放電路徑，能有效阻絕刺激器的高壓破壞。
於前級放大器，低雜訊設計的部份，採用了電路設計技巧以及負載電流分流的方式，把0.1Hz到5kHz的輸入等效雜訊壓到4.04μV，NEF達到3.8。在訊號線性度上，巧妙安排可變增益放大器中的開關位置以及使用rail-to-rail的運算放大器，使得差動輸出訊號在1V的擺幅下，THD可達到0.086%，並大幅縮減了可變電阻的面積。最後，在輸出端加上了一組高頻寬與高slew rate的類比緩衝器，提供系統可做不同頻段訊號偵測的選擇。

Recently there are evidences to show that the over-active neural behavior in specific brain area may cause the syndrome of Parkinson’s disease. Continuous neural signal recording and proper electric stimulation has been clinical proven to be a
possible tool to alleviate the oscillation then calm down the tremble.
In order to capture extremely low frequency neural signals, the DC block capacitor added in front of the sensor would often be with nano-farad scale. This work uses the complementary leakage-balanced structure to form an ultra-high-resistance pseudo resistor for 0.1Hz highpass corner frequency with 60pF input capacitance. For in vivo measurement, recording system always suffer from motion artifact interference and high voltage damage caused by stimulator. The former will be large to saturate amplifier output ; the latter may break the thin gate oxide of input MOS. To overcome this problem, we develop a motion artifact fast recovery loop with the recovery time of 200μs. The PMOS diodes associated with input stage provide dual discharge paths, which can effectively reduce the high voltage damage caused by
stimulator.
By using low noise circuit design skills, input equivalent noise from 0.1Hz to 5kHz down to 4.04μV, and the NEF is 3.8. Thanks for rail-to-rail opamps insertion and smart arrangement for the position of switches in VGA, the THD is 0.086% even if the differential output swing reaching 1V. At output, a high bandwidth and slew rate analog buffer is added to program the LFP or spike mode for neural signal recording.

致謝 I
摘要 III
ABSTRACT V
目錄 VII
圖目錄 IX
表目錄 XIII
第一章 緒論 1
1.1 研究背景 1
1.2 系統簡介 2
1.2.1 系統架構 2
1.2.2 探針模組 3
1.2.3 運動雜訊(motion artifact) 4
1.2.4 低雜訊考量 5
1.3 研究動機 9
1.4 章節簡介 10
第二章 文獻回顧 11
2.1 低功耗低雜訊神經訊號放大器 11
2.2 應用於EEG感測端的8通道主動式微電極系統 14
2.3 具抵抗運動雜訊干擾的生醫訊號感測器 18
2.4 極低面積與功耗之神經訊號感測系統 20
第三章 電路實現 24
3.1 低雜訊放大器(Low Noise Amplifier) 25
3.2 可調變式低通濾波器(Tunable Lowpass Filter) 39
3.3 可變增益放大器(Variable Gain Amplifier) 43
3.4 運動雜訊偵測器(Motion Artifact Detector) 48
3.5 類比緩衝器(Buffer) 54
第四章 量測結果 57
4.1 晶片量測結果 57
4.1.1 低通/高通轉角頻率 57
4.1.2 可調變增益 62
4.1.3 低雜訊性能 65
4.1.4 系統線性度 66
4.1.5 高速感測通道切換 67
4.1.6 運動雜訊消除器 69
4.2 晶片規格與比較表 73
第五章 結論與未來工作 75
5.1 結論 75
5.2 未來工作 75
參考文獻 78

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