Universal biquadratic filters using current conveyors

• Published in: Electronics & communications in Japan. Part 3, Fundamental electronic science Vol. 80; no. 1; pp. 1 - 16
• Main Authors: Nakai, Kazuhiro, Yamamoto, Gaishi
• Format: Journal Article
• Language: English
• Published: New York Wiley Subscription Services, Inc., A Wiley Company 01.01.1997
• Subjects: biquadratic filter; CCII; current conveyor; state variable
• ISSN: 1042-0967; 1520-6440
• DOI: 10.1002/(SICI)1520-6440(199701)80:1<1::AID-ECJC1>3.0.CO;2-V

As an application to active RC circuits in second‐generation current conveyors (CCII), the simultaneous configuration of the lowpass, high‐pass, bandpass, all‐pass, and band‐elimination filters (LPF, HPF, BPF, APF, BEF) is accomplished by changing the state variables in an arbitrary biquadratic transfer function. For BEF, a lowpass notch (LPN) filter (as a lowpass‐type BEF) and a high‐pass notch (HPN) filter (as a high‐pass‐type BEF) were obtained. The constructed circuits are made of five plus‐type CCIIs and can be cascaded. The sensitivity of the passive components and the sensitivity to the voltage‐transfer coefficient and current‐transfer coefficient of the CCII are relatively small. Two types of filter circuits possible for simultaneous configuration are actually fabricated. For one of them, experimental results near 10 kHz, which is a relatively low frequency, are obtained and for the other, results near 100 kHz, a relatively high frequency, are obtained. In each case, the characteristics of the LPF, HPF, BPF, APF, BEF, as well as LPN and HPN, were obtained with Q of 0.7, 1.0, 5.0, and 10.0. In the APF, somewhat nonflat responses are observed near the pole frequency ωo depending on the setting of Q. This case was analyzed. Element sensitivity also was investigated. © 1997 Scripta Technica, Inc. Electron Comm Jpn Pt 3, 80(1): 1–16, 1997