心電圖儀中60赫芝帶拒橢圓濾波電路之設計

心電圖儀監測設備，是擷取人體非常微弱的生理訊號，輸出的訊號準確度經常受到測試環境與設備因素而影響。設計類比濾波電路，主要重視輸出訊號的準確度，使輸出訊號準確的操作在預定的頻率範圍之內，為設計主要考量。運算轉導放大器(Operational Transconductance Amplifier，簡稱OTA)是目前類比電路設計是近年來學者公認最佳的主動元件，其特性為，為輸出電流，為正端輸入電壓，為負端輸入電壓，為轉導增益值，輸入電流I+=I-=0。其除為一主動元件外，轉導增益的Gm值為電子可調外，設計完成的電路不需使用電阻器的優點，讓我們決定選擇它當作本論文設計電路時的主動元件。在電路設計部分，我們將電壓信號轉為電流以方便信號直接加減可節省使用的零件數，根據導納矩陣分析法，將複雜的轉移函數，轉換為導納矩陣方程式，每一個方程式都是簡單的式子，很容易用運算轉導放大器與電容來實現，最後再將全部簡單的電路再重疊起來，就完成符合轉移函數完整電路。設計出來的60赫芝帶拒濾波器電路，並應用在濾除市電，以Hspice 模擬，再探討使用LM13700實現電路，在實現過程中發現LM13700 的Gm值最大與最小只有相差1.94倍，將要使用大量的IC才能實現。因OTA內部電路有一理想電流源，若在未來做成chip，需將內部理想電流源取代成電流鏡，也將由電流控制g值改變成由電壓控制g值，主要是使電路較容易實現。最後，本論文所設計的60赫芝橢圓帶拒濾波電路，期待下線實際做成積體線路，以便實現在心電圖儀中使用。

關鍵字

運算轉導放大器； 60Hz橢圓帶拒濾波器

並列摘要

ECG monitoring equipment that picks up feeble body physical signals and the other hand this usually had a great effect upon the accuracy of the output signals by the test environment and equipment.It designs analog filter circuit that points on the accuracy of the output signal. It can be the output signal makes sure to operation at a predetermined frequency range. OTA (Operational Transconductaance Amplifier) is best candidate for analog filter circuit design identified by savants recently. The main character of OTA is Io=Gm(V+-V-), where Io stands for output current, V+ stands for positive input voltage, V- stands for negative input voltage, Gm stands for trans-conductance value, and the input current I+=I-=0. In addition to an external active components,transduction gain Gm is electrically adjustable outside,the circuit design is complete without the use of the advantages of resistor,so we decided to choose it as the thesis of the active components when designing circuits. Part of the circuit design are the voltage signals into current signals directly to facilitate the addition and subtraction number of parts can be saved,design of the course according to the admittance matrix analysis,complex transfer function, the conversion formula for the admittance matrix,each equation is a simple formula it is easy to use operational amplifiers with capacitive transduction to achieve the final circuit and then again all the simple overlap, to complete a full circuit in line with the transfer function. Design of the 60 Hz band reject filter circuit, it apply to filter in the mains,with Hspice simulation to achieve, we will keep researching in LM13700 to achieve,Found during the LM13700 in the realization of Gm only difference between the maximum and minimum value of 1.94 times,will be used to achieve a large number of IC.OTA circuit has an internal ideal current source, if the future is becomes on chip, inside OTA has a perfect Current source that replace Current mirror, The original value g is controlled by circuit and that change by voltage because the circuit can be easy to achieve. Finally, the paper design of the 60 Hz elliptic filter band reject filter circuit , looking forward to make on chip, in order to achieve the use of ECG.

並列關鍵字

OTA ； 60Hz band reject elliptic filter

參考文獻

[2]M. Bialko and R. W. Newcomb, „Generation of All Finite Linear Circuits Using Integrate DVCCS‟, IEEE Trans. on Circuit Theory,vol. 18, No. 6, Nov. 1971, pp.733–736.

[4]A. S. Sedra, and G. W. Roberts, “Current Conveyor Theory and Practice,” in C. Toumazou, F. J. Lidgey and D. G. Haigh Analogue IC design the current-mode approach (Peter Peregrinus Ltd., London), Chap.3, pp.93-126, 1990.

[5] A. Fabre, “Third-generation current conveyor：a new helpful active element,” Electron. Letters, vol. 31, no. 5, 1995.

[6] C. Toumazou and F. J. Lidgey, „„ Universal active filter using current conveyors,‟‟ Electronics Letters, vol. 22, pp. 662-664, 1986.

[7] Wilson, B., “Recent developments in current conveyors and current-mode circuits,” Circuits, Devices and Systems, IEE Pro.

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心電圖儀中60赫芝帶拒橢圓濾波電路之設計

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