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In this study, we proposed a second-order multifunction filter topology based on a current differencing buffered amplifier. With the proposed topology, five filter functions can be realized. Sensitivity and non-ideal state analyses of the proposed circuit have been performed. In addition to the proposed second-order multifunction filter topology, the third-order quadrature oscillator circuit was operated as the application circuit. In both circuits, the theoretical work and simulation results are in compliance. The proposed design has potential in the medical device design field.

In this work, a novel first order voltage-mode all-pass filter employing single active element named current operational amplifier (COA), two resistors, one capacitor and it’s application as sinusoidal oscillator is presented. The resistors are implemented by using MOSFETs, so the resulting MOS-C circuit is suitable for integration and the central frequency of the filter is electronically tunable. Workability of the proposed filter and it’s application is validated by PSPICE simulation software using TSMC 0.18 micron CMOS model parameters. Simulation results are in good consistency with theoretical analysis. The proposed circuit features precise frequency tuning, operability at low voltage, low distortion and low phase error.

Bu çalışmada,son zamanlarda oldukça fazla dikkat çeken bir aktif eleman olan Terslenmiş Akım Geri Beslemeli İşlemsel Yükselteç (ICFOA) kullanılarak üçüncü dereceden quadrature osilatör devresi sunulmuştur. Topoloji iki adet ICFOA, üç adet kapasitör ve üç adet direnç olmak üzere gerilim modlu ikinci dereceden alçak geçiren filtre ve gerilim modlu integratör yapısının kaskat bağlanıp kapalı çevrim oluşturması ile elde edilmiştir.Sunulan devrenin çalışabilirliği PSPICE benzetim programı ile denenmiş ve teorik sonuçlar ile örtüştüğü görülmüştür. Teorik kesim frekansı 3,979MHzve benzetim sonucu ölçülen kesim frekansı ise 3,933MHz’dir. Benzetimde 0,35 μm MOSIS parametre seti ve ICFOA CMOS yapısı kullanılmıştır. Önerilen devrenin güç tüketimi 4,83mW’dır., In this work, a third-order quadrature oscillator circuit is presented by using an inverting current feedback operational amplifier (ICFOA), an active element that has attracted considerable attention in recent years. The topology consists of two ICFOA, three capacitors and three resistors by connecting a voltage mode second-order low-pass filter and a voltage-mode integrator with a cascaded closed loop. The workability of the circuit is verified by PSPICE simulation program and it is seen that the simulation results verify the theory and the proposed circuit has good performance. The theoretical cut-off frequency is 3.979MHzand the cut-off frequency measured after the simulation is 3.933MHz. In the simulation, 0.35 μm MOSISparameter set and ICFOA CMOS structure are used. The proposedcircuit power consumption is 4.83mW.