- 學位論文
心電圖儀中的Butterworth帶拒濾波電路之設計
Design of Butterworth Band-Reject Filter in ECG
摘要
本論文旨在提出一個在心電圖儀當中去除在60赫茲附近雜訊的四階Butterworth帶拒濾波電路。這個Butterworth濾波電路的設計特色是採用將一個二階Butterworth低通濾波電路的轉移函數經由頻率轉換，s→1/Q(s+1/s) ，得到一個四階Butterworth帶拒濾波電路的轉移函數。所設計的電路為電壓式的電路，電路的設計使用了六個單端接地的運算轉導放大器(OTA)及四個接地電容器。TSMC 0.35μm level-49 H-spice模擬結果得到所設計的Butterworth帶拒濾波信號的頻帶寬相當窄，只從59.309赫茲到61.615赫茲 (即2.306赫茲的頻帶寬)，中心頻率的最小值也相當低，只有0.2637。
並列摘要
In this paper, a Butterworth fourth-order band-reject filter used for eliminating the noise near around 60Hz in ECG is proposed. The design scheme is obtained applying the frequency transformation, s→1/Q(s+1/s), from a second-order low-pass to a fourth-order band-reject filter transfer function. Only employing 6 single-ended-input OTAs and 4 grounded capacitors, a Butterworth voltage-mode fourth-order band-reject filter is innovated. TSMC 0.35μm level-49 H-spice simulation results exhibit that the bandwidth of the band-reject output signal is located from 59.309Hz to 61.615Hz (only 2.306Hz width) and the lowest value at center frequency is only 0.2637.