Realization of some novel active circuits

Abstract

Filter is generic terms used to describe a signal processing block. These are widely used in various areas such as nstrumentation, control system, communication engineering, consumer electronics, industrial electronics and medical electronics. Every year millions of filters are made and used for various applications. It may be difficult to find a modern electronics system that does not use a filter. Mostly these circuits are realized by employing active elements along with passive components such resistors and capacitors. A variety of active elements such as Op- newlineAmp, Operational Transconductance Amplifier (OTA), Fully Differential Difference Amplifier (FDDA), Current Conveyor (CC), Differential Difference Current Conveyor (DDCC) and Dual X-Differential Difference Current Conveyor (DX-DDCC) are presently used for their realization. Most of these devices are current mode devices providing following advantages: higher frequency range of operation, lower power consumption, higher slew rate, improved linearity and better accuracy as compare to the voltage mode. In this thesis we discuss about some novel active devices used for filter realization. Several novel circuits including biquad, waveform generator and elliptical filter have been simulated using PSPICE and most of the them are realized in the laboratory by employing commercially available integrated circuits such as LM741 (Op-Amp), LM13700 (Operational Transconductance Amplifier) and AD844 (Operational Transimpedance Amplifier). There is good match between the theoretical results with the practical and simulation results of all circuits.