Synthesis of a Biquadratic Filter Using Current Conveyor

• Main Authors: Wen-Chieh Chou, 周文介
• Other Authors: Chun-Li Hou
• Format: Others
• Language: zh-TW
• Published: 2004
• Online Access: http://ndltd.ncl.edu.tw/handle/26983820169328502515

碩士 === 中原大學 === 電子工程研究所 === 92 === 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.