一個以電流傳輸器合成之二階濾波器

Synthesis of a Biquadratic Filter Using Current Conveyor

周文介(Wen-Chieh Chou)

指導教授 ： 侯俊禮

中原大學/工學院/電子工程研究所/碩士(2004年)

https://doi.org/10.6840/cycu200400242

摘要

本論文提出使用電流式元件:差動差分電流傳輸器(DDCC)及多輸出第二代電流傳輸器(MOCCII)合成一修改過的直接形式(direct-form)的二階濾波器。其優點是可以由被動元件與信號流程圖的直接對應關係來調整電路架構中的被動元件而得到想要實現的二階濾波器架構。並利用連接於多輸出第二代電流傳輸器(MOCCII)的電阻器來控制回授及前授比例。所提出的二階濾波器架構擁有高輸入阻抗，因此適合串接(cascadable)。本電路使用了兩個接地電容器，適合於積體電路上實現。電路架構以Hspice搭配UMC 0.5微米的製程參數模擬，得到的結果與理論相符。本論文另外提出了以二階濾波器為基礎架構的多相振盪器合成方法。僅需將濾波器的帶通輸出端接回到濾波器的輸入端，就可以實現此振盪器。另外可在原本濾波器的低通與高通輸出端分別得到一個相位領先九十度與相位落後九十度的振盪波形，若於高通輸出端串接一積分器，則可得到一個四相振盪器(biquadratic oscillator)。在適當的Q值與振盪頻率的調整下，此方法可以應用於多種不同架構的濾波器來實現多相振盪器。我們使用了一個由電流回授放大器(CFA)所合成的二階濾波器，以電子電路實驗方式來驗證此方法。

關鍵字

二階濾波器 ； 電流傳輸器

並列摘要

This thesis uses two kinds of current-mode elements, the differential difference current conveyors (DDCC’s) and the multi-output second-generation current conveyors (MOCCII’s), to synthesize a modified direct-form biquadratic filter. The resistors in connection with the MOCCII’s are exploited to control the feedback and feedforward ratios. The proposed circuit has high input impedance and thus is cascadeable. It employs two grounded capacitors and is suitable for integrated circuits. Hspice simulations applying UMC 0.5um technology process parameters which coincides these analyses in this paper are also given. A method to obtain multi-phase oscillation response from a biquadratic filter structure is also proposed. Simply by connecting the bandpass output of the biquadratic filter to the input of it, the multi-phase oscillation response can be derived. And for the original lowpass and highpass outputs, oscillation waveforms which leads and legs 90° the waveform at the bandpass output are exhibited, respectively. If an integrator is connected to the highpass output, a biquadratic oscillation response can be derived. Under proper Q value and oscillation frequency adjustments, this method can be applied to various biquad structures. An experiment applying a biquadratic filter synthesized with the Current Feedback Amplifiers (CFA’s) is presented to verify this method.

並列關鍵字

biquadratic filter ； current conveyor

參考文獻

3. M. Sagbas, K. Fidanboylu, “Electronically tunable current-mode second-order universal filter using minimum elements,” Electronics Letters, vol.40, pp.2-4, 2004.

4. C. M. Chang, B. M. Al-Hashimi, C. L. Wang, and C. W. Hung, “Single fully differential current conveyor biquad filters,” IEE Proc. Circuits, Devices, and Systems, vol.150, no.5, pp.394-398, 2003.

5. A. Jiraseree-amornkun, N. Fujii, and W. Surakampontorn, “Realization of electronically tunable ladder filters using multi-output current controlled conveyors,” ISCAS '03, vol.1, no.19, pp.I-541-I-544, 2003.

7. C. M. Chang, C. S. Hwang, and S. H. Tu, “Voltage-mode notch, lowpass, and bandpass filter using current-feedback amplifiers,” Electronics Letters, vol.30, no.24, pp.2022-2023, 1994.

9. H. A. Alzaher, H. Elwan, and M. Ismail, “A CMOS fully balanced second-generation current conveyor,” IEEE Trans. Circuits and Systems II, vol.50, no.12, pp.278-287, 2003.