A new electronically tunable allpass filter (ETAF) realization using the composite Current Feedback Amplifier (CFA) and Multiplication Mode Current Conveyor (MMCC) building blocks is proposed. First order non-minimum phase function with electronically variable output phase is derived. Extension of the filter to a linear quadrature-VCO design is then implemented. Simulation test responses of all these functions are satisfactorily verified.
New realisation scheme of linear voltage-controlled quadrature oscillator (QO) is proposed. The active building block is electronically tunable (ET) differential voltage current conveyor transconductance (g m) amplifier configured with current feedback amplifier and multiplication mode current conveyor devices. The designs are essentially tuned-inductor-capacitor oscillator, wherein the electronically variable lossless grounded inductor (L) had been simulated at suitable nodes of the active building block. Subsequently, with slight modification of the block, an ET floating-lossless immittance function generation is presented. Effects of device port mismatch error and parasitic capacitances are analysed. Albeit sensitivity relative to port mismatch error is negligible, the parasitic components tend to limit the higher-usable frequency range; appropriate design equations are derived for a true bilinear admittance function realisation and their applications to filter and sinusoid oscillator design are included. Experimental results on the QO with linear f o-tuning law are satisfactorily verified up to 8.7 MHz at low total harmonic distortion.
A simple first order allpass filter (APF) realization scheme with single current feedback amplifier (CFA) is presented; the phase-select component Y (= sC) is grounded. Analysis indicates that effects of imperfect port mismatch ratio of the CFA are quite insignificant. However the device parasitic capacitors introduce certain phase error at relatively higher frequencies. This simple circuit may be extended to second order APF design, if desired with Y as a shunt −LC resonator; L being a lossless inductor simulated by a DVCCTA element. Literature study on recent first order APF indicates that these are based on active elements that are based essentially on assorted conjoined versions of two types of devices.
A new voltage-variable inductor (VVI)-L realization scheme using composite Current Feedback Amplifier (CFA) and Multiplication Mode Current Conveyor (MMCC) active building block (ABB) is presented. Subsequently a LC-type voltage controlled quadrature oscillator (VCQO) with linear tuning law is derived by replacing the CFA by another MMCC. Experimental results based on PSPICE simulation and hardware circuitry for a linear tuning range of oscillation frequency (f o) ∼9.3 MHz with satisfactory phase-noise figure on the wave generation, had been verified. Effects of the ABB nonidealities are shown to be insignificant.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.