The paper presents an improved equivalent circuit parameters extraction method for the dumbbell-shaped defected ground structure (DGS). The new extraction parameters equations are obtained in closed-form expressions, ...
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The paper presents an improved equivalent circuit parameters extraction method for the dumbbell-shaped defected ground structure (DGS). The new extraction parameters equations are obtained in closed-form expressions, which contain S11 and S21. The DGS unit with center frequency of 5 GHz is designed and fabricated on a TLX substrate with thickness of 1 mm and dielectric constant of 2.55. The circuit simulated results are in good agreement with the measured results. This parameters extraction method can be widely used for the design and analysis of DGS .
The constant modulus algorithm (CMA) has been widely used in the blind equalization of quadrature amplitude modulation (QAM) signals, but it has slow convergence rate and large steady state mean square error and the p...
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The constant modulus algorithm (CMA) is one widely used algorithm for blind equalization of quadrature amplitude modulation (QAM) signals. The algorithm exhibits slow convergence rate and large steady state mean squar...
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The carrier recovery is one key technique in the demodulation of high order quadrature amplitude modulation (QAM) signals. A carrier recovery algorithm which switches between multi-threshold polarity decision mode and...
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There many researches about modulation mode classification of the MPSK signals, but these studies pay few attentions to some especial MPSK signals such as OQPSK or pi/4QPSK. However, the signals are very important in ...
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ISBN:
(纸本)9781424437092
There many researches about modulation mode classification of the MPSK signals, but these studies pay few attentions to some especial MPSK signals such as OQPSK or pi/4QPSK. However, the signals are very important in the digital communications. The method of classification of the QPSK, OQPSK, pi/4QPSK and 8PSK has discussed in this paper, because these MPSK signals have similar constellations or spectrum. The method of the classification and parameter estimation based on the statistical and spectral characters of the instantaneous phase difference (IPD) is proposed. The simulation results of the digital signals indicate that this method is availability when the SNR is higher than 5dB.
It is unfeasible to analyze the security events by the manual way for the security manager, because the number of the events is huge and the information contained in the events is meaningless. After analyzing the exis...
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The empirical mode decomposition (EMD) method for analysing nonlinear and non-stationary data has attracted great research interests. Because, the PAM-DS UWB signal which has the property of transient and low probabil...
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The constant modulus algorithm (CMA) is one widely used algorithm for blind equalization of QAM signals. The algorithm exhibits slow convergence rate and large steady state mean square error and the phase-blind nature...
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ISBN:
(纸本)9781934142141
The constant modulus algorithm (CMA) is one widely used algorithm for blind equalization of QAM signals. The algorithm exhibits slow convergence rate and large steady state mean square error and the phase-blind nature in comparison with the algorithms used in conventional data-aided equalization schemes. In this paper, a variable step size modified constant modulus algorithm is proposed. The proposed algorithm can speed up convergence rate and decrease steady state mean square error and correct phase error and frequency offset at the same time. The simulation results demonstrate the effectiveness of the proposed algorithm in improving convergence rate and reducing steady state mean square error.
GPS signal is very weak and easily influenced by interference or jamming. An antenna array with adaptive algorithm combing with temporal anti-jamming processing can be used to mitigate interference and improve GPS sig...
GPS signal is very weak and easily influenced by interference or jamming. An antenna array with adaptive algorithm combing with temporal anti-jamming processing can be used to mitigate interference and improve GPS signal acquisition and tracking performance. This paper addresses an all digital temporal and spatial anti-jamming implementation scheme based on adaptive antenna array. Temporal adaptive Altering techniques can effectively suppress narrowband interference, which is less ability to code with broadband interference. However, the presence of an antenna array allows the receiver to operate in spatial domain in addition to time or frequency domain, which can improve the performance of GPS receiver with broadband interference. Simulation results show the scheme can greatly enhance the robustness of GPS receiver in a large number of interference signals.
In this paper, passive localization from a single satellite is addressed. Passive localization is a typical nonlinear filtering and optimal estimation problem, and usually suffers large initial estimation error and lo...
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ISBN:
(纸本)9781424465392;9781424465422
In this paper, passive localization from a single satellite is addressed. Passive localization is a typical nonlinear filtering and optimal estimation problem, and usually suffers large initial estimation error and low observability. When localizing an emitter located at the surface of the earth, the localization problem needs to satisfy the constraint condition of the earth surface. Particle swarm optimization(PSO) provides an evolutionary computation method to solve the constrained nonlinear optimal problem. However, it is not applicable straightforwardly to constrained optimal problem. Considering the constraint in single satellite passive localization, a new algorithm based on PSO is proposed. This algorithm can reduce the PSO searching dimension using the nonlinear constraint condition. Computer simulation experiments are performed to show the effectiveness of the proposed algorithm.
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