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FPGA realization of ALU for mobile GPU

Arithmetic Logic Unit (ALU) is the most important component of processors. All arithmetic and logical computations are performed inside the ALU. This paper presents the design and the implementation of the ALU. The design is based on Approximated Precision Shader and Look-Up Table (LUT) multiplier. The lookup table, Wallace tree, and Carry Look-ahead Adder (CLA) are used in combination to speed up

Circuit Theory and Applications
Software and Communications

Emulation of current excited fractional-order capacitors and inductors using OTA topologies

A novel topology suitable for emulating fractional-order capacitors and inductors using current excitation is achieved using a fractional-order differentiator/integrator block and appropriately configured Operational Transconductance Amplifiers. The scheme is capable of emulating both fractional-order capacitors and fractional-order inductors without any modifications to its structure. This

Circuit Theory and Applications

Power and energy analysis of fractional-order electrical energy storage devices

Characterizing and modeling electrical energy storage devices is essential for their proper integration in larger systems. However, basic circuit elements, i.e. resistors, inductors, and capacitors, are not well-suited to explain their complex frequency-dependent behaviors. Instead, fractional-order models, which are based on non-integer-order differential equations in the time-domain and include

Circuit Theory and Applications

On inverse problem of generalized synchronization between different dimensional integer-order and fractional-order chaotic systems

Chaos is described as a unstable dynamic behavior with dependence on initial conditions. The control and synchronization of chaotic systems requires the knowledge of parameters in advance. Recently researcher's has been shifted from integer order chaotic system to fraction order chaotic system. In this work, based on the stability theory of integer-order linear systems and Lyapunov stability

Circuit Theory and Applications

A low frequency oscillator using a super-capacitor

A low frequency relaxation oscillator is designed using a super-capacitor. An accurate analytical expression for the oscillation frequency is derived based on a fractional-order super-capacitor model composed of a resistance in series with a Constant Phase Element (CPE) whose pseudo-capacitance and dispersion coefficient are determined using impedance spectroscopy measurements. Experimental

Circuit Theory and Applications

Spectral Capacitance of Series and Parallel Combinations of Supercapacitors

The porous nature of the electrode material in supercapacitors and the apparent conductivity of the electrolyte cause their impedance to show a complex frequency-dependent behavior, which in turn makes it incorrect to treat them as ideal capacitors, even at a frequency of a few millihertz. This is particularly crucial if the intended application requires a configuration that uses stacked

Circuit Theory and Applications

Fractional-order Fitzhugh-Nagumo and Izhikevich neuron models

This paper studies the famous Fitzhugh-Nagumo and Izhikevich neuron models in the fractional-order domain. Generalization of the integer models into the fractional-order domain providing a wider scope understanding of the neuron systems. The fractional Fitzhugh-Nagumo circuit model and the state space equations are introduced. Different fractional orders are studied as an example. Numerical

Circuit Theory and Applications

Two-port two impedances fractional order oscillators

This paper presents a study for general fractional order oscillator based on two port network where two topologies of oscillator structure with two impedances are discussed. The two impedances are chosen to be fractional elements which give four combinations for each topology. The general oscillation frequency, condition and the phase difference between the two oscillatory outputs are deduced in

Circuit Theory and Applications

A mathematical model of an ideally threshold compensated rectifier for RF energy harvesting

This paper introduces a mathematical model of an ideally threshold compensated rectifier for RF energy harvesting. The ideally compensation arrangement has been exploited to improve the rectifier's performance and overcome the limitation of rectifier's sensitivity which mainly depends on the threshold voltage of the rectifying devices (transistors). The model considers the conduction angle and the

Circuit Theory and Applications

Charging and discharging RCα circuit under Riemann-Liouville and Caputo fractional derivatives

In this paper, the effect of non-zero initial condition on the time domain responses of fractional-order systems using Caputo and Riemann-Liouville (RL) fractional definitions are discussed. Analytical formulas were derived for the step and square wave responses of fractional-order RCα circuit under RL and Caputo operators for non-zero initial condition. Moreover, a simulation scheme for

Circuit Theory and Applications