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Parameter Estimation of Multi-component chirp signal Based on Differential Evolution

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Instrumentation 2017年第2期4卷 34-43页

作者： ZHAO Haoran MENG Fankuo QIAO Liyan Department of Automatic Test and Control Harbin Institute of Technology

chirp signals show energy aggregation in the fractional Fourier domain(FrFD) w hich can be used to estimate the parameter of the signals. In this paper,a parameter estimation method for multi-component chirp signal w hich corrupted by w hite Gaussian noise is proposed based on the discrete fractional Fourier transform(DFrFT) and the differential evolution( DE) algorithm. The proposed algorithm uses the DE algorithm instead of the conventional fine search algorithm to detect the peak of the signals in the FrFD. The paper simulated the influence of the noise and the resolution of the proposed algorithm. The results of the simulation show the proposed method does not only improve the estimation accuracy of the peak coordinate,but also reduces time consuming.

关键词： chirp signal Fractional Fourier Transform Parameter Estimation Differential Evolution

The Sidelobe Suppressing Methods for chirp signal Pulse Compression

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The Sidelobe Suppressing Methods for Chirp Signal Pulse Comp...

A reduced order model for coupled mode cascade flutter analysis

第三届国际仪器科学技术学术研讨会

作者： HU Hang Dept. of Electronics & Communication Engineering Harbin Institute of Technology Harbin 150001 China

Pulse compression technique is widely used in modern radar system and the sidelobe suppression is an important topic for the pulse compression technique. For the sidelobe suppression of the pulse comp

关键词： Pulse compression chirp signal sidelobe suppression weighting

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Chinese Journal of Aeronautics 2022年第10期35卷 176-182页

作者： Huang HUANG Xinkai JIA Jia REN Bochao CAO Dingxi WANG Xiuquan HUANG School of Power and Energy Northwestern Polytechnical UniversityXi'an 710072China Yangtze River Delta Research Institute of Northwestern Polytechnical University Taicang 215400China Department of Aeronautics and Astronautics Fudan UniversityShanghai 200433China

A Reduced Order Model(ROM)based analysis method for turbomachinery cascade coupled mode flutter is presented in this *** unsteady aerodynamic model is established by a system identification technique combined with a set of Aerodynamic Influence Coefficients(AIC).Subsequently,the aerodynamic model is encoded into the state space and then coupled with the structural dynamic equations,resulting in a ROM of the cascade *** cascade flutter can be determined by solving the eigenvalues of the ***-torsional coupled mode flutter analysis for the Standard Configuration Eleven(SC11)cascade is used to validate the proposed method.

关键词： Aerodynamic influence coefficients chirp signal Coupled mode flutter Eigenvalue problem Reduced order model

Fractional Fourier domain hopped communication method based on chirp modulation for underwater acoustic channels

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Journal of Systems Engineering and Electronics 2017年第3期28卷 449-456页

作者： Xingbin Tu Xiaomei Xu Zheguang Zou Liangliang Yang Jianming Wu College of Ocean and Earth Science Xiamen UniversityXiamen 361102China Key Laboratory of Underwater Acoustic Communication and Marine Information Technology Ministry of EducationXiamen 361005China

To improve the data rate of underwater acoustic frequency-hopped communications, frequency hopping is applied to different orders of fractional Fourier domain (FrFD), to enable non-intrusive, bandwidth-limited acoustic communications. An FrFD frequency-hopped communication method based on chirp modulation, namely multiple chirp shift keying-FrFD hopping (MCSK-FrFDH), is proposed for underwater acoustic channels. Validated by both simulations and experimental results, this method can reach a bandwidth efficiency twice more than conventional frequency-hopped methods with the same data rate and anti-multipath capability, suggesting that the proposed method achieves a better performance than the traditional frequency hopped communication in underwater acoustic communication channels. Results also show that in practical scenarios, the MCSK-FrFDH system with longer symbol length performs better at the low signal-to-noise ratio (SNR), while the system with larger frequency sweeping range performs better at a high SNR.

关键词： underwater acoustic communication fractional Fourier domain (FrFD) frequency hopping chirp signal

Cyclic beamforming using fractional Fourier transform domain cyclostationarity

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High Technology Letters 2011年第1期17卷 57-63页

作者： Muhammad Ishtiaq Ahmad Liu Zhiwen Xu Yougen School of Information ＆ Electronics Beijing Institute of Technology Beijing 100081 P. R. China

A minimum mean-squared error （MSE） beamforming algorithm employing the optimum fractional Fourier transform （Opt-FrFT） domain second-order cyclostationarity is proposed. This method can efficiently filter out the compact desired chirp signal, with a consequence that the cyclically uncorrelated interferences and stationary （colored） Gaussian noise are greatly suppressed in the Opt- FrFT domain. This improves the MSE minimization cyclic beamformer by reducing effectively the Opt-FrFY domain signal-noise cross terms in the presence of finite data length de-correlation operation. Simulation results show that the new method works well under a wide range of signal-to-noise ratio （SNR） and signal-to-interference ratio （SIR）.

关键词： beamforming fractional Fourier transform chirp signal cyclostationarity

Oversampling analysis in fractional Fourier domain

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Science in China(Series F) 2009年第8期52卷 1446-1455页

作者： ZHANG Feng TAO Ran WANG Yue Department of Electronic Engineering Beijing Institute of Technology Beijing 100081 China

Oversampling is widely used in practical applications of digital signal processing. As the fractional Fourier transform has been developed and applied in signal processing fields, it is necessary to consider the oversampling theorem in the fractional Fourier domain. In this paper, the oversampling theorem in the fractional Fourier domain is analyzed. The fractional Fourier spectral relation between the original oversampled sequence and its subsequences is derived first, and then the expression for exact reconstruction of the missing samples in terms of the subsequences is obtained. Moreover, by taking a chirp signal as an example, it is shown that, reconstruction of the missing samples in the oversampled signal is suitable in the fractional Fourier domain for the signal whose time-frequency distribution has the minimum support in the fractional Fourier domain.

关键词： fractional Fourier transform oversampling chirp signal

Joint Timing and Frequency Synchronization for OFDM based on Fractional Fourier Transform

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China Communications 2010年第5期7卷 93-102页

作者： Tang Xun Sha Xuejun School of Electronic and Information Engineering Harbin Institute of Technology Harbin 150001 P. R. China

In this paper a joint timing and frequency synchronization method based on Fractional Fourier Transform （FIFT） is proposed for Orthogonal Frequency-Division Multiplexing （OFDM） system. The combination of two chirp signals with opposite chirp rates are used as the training signal, the received training signal with timing and frequency offset is transformed by FrFT and the two peaks representing two chirps in FrFT domain are detected, then the position coordinates of the two peaks are precisely corrected and substituted into an equation group to calculate timing and frequency offset simultaneously. This method only needs one FrFT calculation to implement synchronization, the computational complexity is equal to that of FFT and less than that of correlation or maximum likelihood calculation of existing methods, and estimation range of frequency offset is Large, greater than half the signal bandwidth, while the simulation results show that even at low SNR it can accurately estimate timing and frequency offset and the estimation error is less than that of existing methods.

关键词： synchronization Fractional Fourier transform chirp signal OFDM

Enhancement Channel Estimation Using Outer-Product Decomposition Algorithm Based on Frequency Transformation

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Journal of Marine Science and Application 2020年第2期19卷 283-292页

作者： Xiukun Li Ji Wang Dexin Zhao Acoustic Science and Technology Laboratory Harbin Engineering UniversityHarbin 150001China Key Laboratory of Marine Information Acquisition and Security(Harbin Engineering University) Ministry of Industry and Information TechnologyHarbin 150001China College of Underwater Acoustic Engineering Harbin Engineering UniversityHarbin 150001China Advanced Interdisciplinary Technology Research Center National Innovation Institute of Defense TechnologyBeijing 100010China

The outer-product decomposition algorithm(OPDA)performs well at blindly identifying system ***,the direct use of the OPDA in systems using bandpass source will lead to *** study proposes an approach to enhance the channel estimation quality of a bandpass source that uses *** approach performs frequency domain transformation on the received signal and obtains the optimal transformation parameter by minimizing the p-norm of an error ***,the proposed approach extends the application of OPDA from a white source to a bandpass white source or chirp *** formulas and simulation results show that the proposed approach not only reduces the estimation error but also accelerates the algorithm in a bandpass system,thus being highly feasible in practical blind system identification applications.

关键词： Blind identification Outer-product decomposition algorithm Bandpass white signal chirp signal Second-order statistics

To Generate UWB Impulses Suppressing Co-channel Interference with Narrow Band Systems

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To Generate UWB Impulses Suppressing Co-channel Interference...