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Your search keyword '"Harb, Ahmad M."' showing total 3 results
Start Over Author "Harb, Ahmad M." Topic phase-locked loops
3 results on '"Harb, Ahmad M."'

1. Chaos Control of Third Order Phase Locked Loop Using Sliding Mode Nonlinear Controller.

Author

Harb, Bassam A., Harb, Ahmad M., and Al-Ajlouni, Ahmad F.

Subjects
SLIDING mode control, PHASE-locked loops, CONTROL theory (Engineering), BIFURCATION theory, MATHEMATICAL analysis
Abstract

The nonlinear dynamics of a third-order phase locked loop (PLL) reveals a chaotic behavior for range values of loop parameter. Using bifurcation theory, it has been verified through mathematical analysis and simulation that such behavior pulls the PLL to an undesirable and unstable out-of-lock state. This paper aims to control such chaotic behavior and drive the PLL to the in-lock state, by applying a nonlinear controller based on sliding mode control theory to the PLL under consideration. The design process involves two phases. In the first phase, a sliding surface is designed such that the sliding motion meets the design specifications. In the second phase, a high-speed switching control law is selected such that the system state trajectory reaches the sliding surface. The validity of the proposed controller is tested through simulations. Results show the effectiveness of the designed nonlinear controller in stabilizing the system and driving the PLL to the phase locked state. [ABSTRACT FROM AUTHOR]

Published
2019
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2. Chaos control of third-order phase-locked loops using backstepping nonlinear controller

Author

Harb, Ahmad M. and Harb, Bassam A.

Subjects
*PHASE-locked loops, *SINE function, *PHASE detectors, *HOPF algebras
Abstract

Previous study showed that a third-order phase-locked loop (PLL) with sinusoidal phase detector characteristics experienced a Hopf bifurcation point as well as chaotic behavior. As a result, this behavior drives the PLL to the out-of-lock (unstable) state. The analysis was based on a modern nonlinear theory such as bifurcation and chaos. The main goal of this paper is to control this chaotic behavior. A nonlinear controller based on the theory of backstepping is designed. The study showed the effectiveness of the designed nonlinear controller in controlling the undesirable unstable behavior and pulling the PLL back to the in-lock state. [Copyright &y& Elsevier]

Published
2004
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3. Chaos and bifurcation in a third-order phase locked loop

Author

Harb, Bassam A. and Harb, Ahmad. M.

Subjects
*CHAOS theory, *PHASE-locked loops, *NONLINEAR theories
Abstract

The chaos induced in a new type of phase locked loop (PLL) having a second-order loop filter is investigated. The system under consideration is modeled as a third-order autonomous system with sinusoidal phase detector characteristics. The modern of nonlinear theory such as bifurcation and chaos is applied to a third-order of PLL. A method is developed to quantitatively study the type of bifurcations that occur in this type of PLL’s. The study showed that PLL experiencing a Hopf bifurcation point as well as chaotic behaviour. The method of multiple scales is used to find the normal form near the Hopf bifurcation point. The point is found to be supercritical one. [Copyright &y& Elsevier]

Published
2004
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