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Hu W.,Nanjing University of Aeronautics and Astronautics | Hu W.,Nanjing Changjiang Electronics Group Co. | Li J.-P.,Nanjing University of Aeronautics and Astronautics | Zhang G.,Nanjing University of Aeronautics and Astronautics | And 2 more authors.
Wuli Xuebao/Acta Physica Sinica | Year: 2012

We proposed a new chaotic system using the closed loop self-feedback frequency modulation (FM) technique where the current sample of the output signal of voltage-controlled oscillator (VCO) is transformed and used as the next input of VCO. The dynamical behavior of the system is investigated by Bifurcation diagram and Lyapunov exponents. The performance of the system is analyzed in terms of peak to average power ratio (PAPR), frequency spectrum and the correlation function of the output signal. The results show that the developed system has complicated dynamical behaviors, including bifurcation, multi-stability and chaos, and the generated chaotic signals have low PAPR and wide bandwidth. We also discussed the synchronization of the system by FM code. In circuit experiments, VCO is implemented by digital frequency synthesis. The experimental results are consistent with our theoretical analysis. © 2012 Chinese Physical Society. Source

Jianguo M.,Nanjing University of Aeronautics and Astronautics | huiyu Z.,Nanjing University of Aeronautics and Astronautics | Guangmin L.,Nanjing University of Aeronautics and Astronautics | Jiankang X.,Nanjing Changjiang Electronics Group Co.
Applied Mechanics and Materials | Year: 2013

This template explains a design of a fuzzy temperature control system for the pressuresensitive paint. According to the relationship between temperature difference and the current of semiconductor chip, the fuzzy system control theory, control the volume of the domain, control rules design, and design a constant current source circuit to control the current through the chip, and finally make experimental verification of the system. The system hardware uses C8051F040 MCU, temperature chip DS18B20, keyboard chip CH451. © (2013) Trans Tech Publications, Switzerland. Source

Hu W.,Nanjing University of Aeronautics and Astronautics | Hu W.,Nanjing Changjiang Electronics Group Co. | Bao B.,Jiangsu Teachers University of Technology | Zhang G.,Nanjing University of Aeronautics and Astronautics | And 3 more authors.
Dongnan Daxue Xuebao (Ziran Kexue Ban)/Journal of Southeast University (Natural Science Edition) | Year: 2010

The blind identification of linear convolution systems driven by a piecewise linear continuous chaotic signal was researched, and a chaos synchronization based identification approach for linear convolution systems is proposed. By utilizing linear matrix inequality (LMI) and chaos synchronization systems, a least square based observer was constructed and minimized by an adaptive algorithm to estimate the parameter of linear convolution systems. A simple piecewise linear chaotic system was used in simulation analysis. The numerical simulation results are consistent with theoretical analysis results, which demonstrate that the proposed approach can identify the convolution systems. And the proposed approach converges only after about ten iterations. The proposed approach is more robust than the traditional Bussgang algorithm. When input SNR is 15 dB, the output SNR (signal to noise ratio) of the proposed approach is 10 dB higher than that of the Bussgang algorithm. And even when imput SNR in 0 dB the proposed approach has output SNR of 5 dB. Source

Sun W.,Nanjing University of Information Science and Technology | Sun W.,Nanjing Southeast University | Zhang X.,Nanjing University of Information Science and Technology | Sun Y.,Nanjing Changjiang Electronics Group Co. | And 2 more authors.
High Technology Letters | Year: 2012

According to the chroma distribution diversity (CDD) between lip color and skin color, the lip color area is segmented by the back propagation neural network (BPNN) with three typical color features. Isolated noisy points of the lip color area in binary image are eliminated by a proposed region connecting algorithm. An improved integral projection algorithm is presented to locate the lip boundary. Whether a driver is fatigued is recognized by the ratio of the frame number of the images with mouth opening continuously to the total image frame number in every 20 s. The experiments show that the proposed algorithm provides higher correct rate and reliability for fatigue driving detection, and is superior to the single color feature-based method in the lip color segmention. Besides, it improves obviously the accuracy and speed of the lip boundary location compared with the traditional integral projection algorithm. Copyright © by HIGH TECHNOLOGY LETTERS PRESS. Source

Wang X.-D.,Nanjing University of Aeronautics and Astronautics | Wang X.-D.,Nanjing Changjiang Electronics Group Co. | Fan T.,Nanjing University of Aeronautics and Astronautics | Huang Q.-H.,Nanjing Changjiang Electronics Group Co. | Zheng B.-S.,Nanjing University of Aeronautics and Astronautics
Tien Tzu Hsueh Pao/Acta Electronica Sinica | Year: 2016

SOQPSK signal has constant envelope and continuous phase, and has high power and spectral efficiency. It will have broad application prospects in satellite communications, deep space communications and aeronautical telemetry systems. To ensure SOQPSK carrier signal can be applied to larger Doppler offset system, this paper presents a SOQPSK signal carrier tracking technology which uses FFT guide COSTAS loop. First, a rough estimate by FFT of the Doppler frequency makes carrier frequency offset be limited to a small range, and then uses the improved COSTAS loop to track carrier residuals and phase error, thus achieving a steady carrier track for SOQPSK signal with large carrier frequency offset. Simulation results show that the proposed algorithm not only is able to track large carrier frequency offset, but also is better to track small frequency offsets than traditional methods. © 2016, Chinese Institute of Electronics. All right reserved. Source

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