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Doppler radar by using single multicarrier pulse based on optical fibre delay lines

Journal of Systems Engineering and Electronics 2010年第3期21卷 404-407页

作者： Junqi Duan Zishu He National Information Control Laboratory Chengdu 610036 P. R. China Department of Electronic Engineering University of Electronic Science and Technology of China Chengdu 610054 P. R. China

The proposed Doppler measurement technique shows that the Doppler measurements can be accomplished by a single pulse with multiple frequency components through optical fibre delay *** and velocity ambiguity can be removed,and the velocity resolution can be improved dramatically by using long optical fibre delay ***,the velocity resolution can be modified by adjusting the length of optical fibre delay *** addition,the proposed radar can achieve high range resolution by using a single wideband *** a result,the new approach can improve radar performance significantly.

关键词： Doppler radar matched filters optical delay lines radar signal processing radar system velocity measurement.

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Signal processing technique for randomly discontinuous spectra HF radar waveforms

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Journal of Systems Engineering and Electronics 2004年第4期15卷 511-515,524页

作者： ZhangDongpo LiuXingzhao DepartmentofElectronicEngineering ShanghaiJiaotongUniversityShanghai200030P.R.China

A major problem with all high frequency (HF) radars is a relatively poor range resolution available due to many interference soturces. To avoid the interferences in frequency domain and operate with widehand, the randomly discontinuous spectra (RDS) signal is employed. However, it results in high range sidelobes when matching the reflected echo, which is much more difficult for target detection. A new signal processing technique that is radically different from the conventional technique to lower range sidelobes is introduced. This method is based on suppressing the selfclutter of the radar range ambiguity {unction (AF) by mismatched filtering. An effective algorithm is adopted to solve the filter coefficients. Simulation results show that the peak sidelobe level can be reduced to -30dB and the achievable system bandwidth is about 400KHz. The technique is adaptable to practical radar systems and applicable for other realtime signal processing.

关键词： Radar Radar signal processing Signal processing algorithms Simulation Signal to noise ratio matched filters

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Windowed overlapped frequency domain block filtering approach for direct sequence signal acquisition

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Digital Communications and Networks 2018年第3期4卷 209-216页

作者： Ebrahim Karami Harri Saarnisaari Department of Engineerng and Applied Sciences Memorial University Canada Centre for Wireless Communications University of Oulu Finland

This study applies a windowed frequency domain overlapped block filtering approach to acquire direct sequence signals. As a novel viewpoint, the windows not only allow pulse shaping without front-end pulse-shaping filter, but also increase the performance of the spectrum sensing unit, which can efficiently be implemented into this frequency domain receiver and may further be used for spectrum sensing in cognitive radios or narrowband interference cancellation in military radios. The proposed receiver is applicable for the initial time synchroni- zation of different signals containing a preamble. These signals include single carrier, constant envelope single carder, multicarrier, and even generalized multicarrier signals, making the proposed receiver structure a universal unit. Furthermore, the receiver can be used to perform filtering with long codes and compute the sliding correlation of an unknown periodic preamble. The receiver can further be modified to handle large Doppler shifts. We will also demonstrate herein the computational complexity and analysis of the acquisition performance in Rayleigh and Rician fading channels.

关键词： Synchronization Pseudonoise coded communication matched filters

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MAGNITUDE RESPONSE OPTIMIZATION OF DELTA OPERATOR filters

MAGNITUDE RESPONSE OPTIMIZATION OF DELTA OPERATOR FILTERS

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1996 3rd International Conference on Signal Processing(ICSP’96)

作者： P.Taneli Harju Juha Kauraniemi Seppo J.Ovaska Laboratory of Telecommunications Technology Helsinki University of Technology Laboratory of Signal Processing and Computer Technology Helsinki University of Technology

＜正＞Digital filters that use the delta operator have been shown to be less sensitive to filter coefficient quantization than filters using the shift operator when the poles and zeroes lie near the point z=±*** is customary to simply round the prototype filter coefficients to the nearest fixed-point numbers for the *** this paper,we show that when very few bits are allocated for each coefficient in a delta filter,some other quantized point than the directly rounded point is likely to offer magnitude response that more closely matches the required characteristics. Furthermore,a neighborhood search may even find a solution that fulfills the given specifications with fewer bits than by using direct *** is of particular importance in Application-Specific Integrated Circuit implementations where expensive die area can be saved by using fewer bits to represent a *** experiments also confirm the result that delta parameterization regularly requires at least two or three bits less than shift parameterization to fulfill the same narrowband filter specifications.

关键词： Digital filters Quantization IIR filters Application specific integrated circuits Prototypes Narrowband Laboratories Signal processing Telecommunication computing matched filters

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Resolution enhancement with improved range Doppler algorithm in high numerical aperture OCT

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Chinese Optics Letters 2011年第12期9卷 55-58页

作者：陈晓冬雷湧汪毅郁道银 College of Precision Instrument and Opto-Electronic Engineering Tianjin University Opto-Electronic Information Science and Technical Lab Ministry of EducationTianjin University

The improved range Doppler algorithm is proposed to abate the trade-off between resolutions and depth of focus in spectral domain optical coherence tomography. By considering the finite beam width and the shape of the wavefronts produced by the Gaussian beam, a physical diffraction model is presented to simulate the light propagation process in the sample. The two-dimensional processing of the spectrum data is decomposed into two one-dimensional processings of Stolt transform and matched filter. Experimental results show that image reconstruction can be achieved. The transverse and axial resolutions are both improved significantly, especially in the out-of-focus range, and the resolutions are almost equivalent throughout the entire region of interest.

关键词： Algorithms Image reconstruction matched filters Optical tomography Processing

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Voltage-controlled optical filter based on electrowetting

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Chinese Optics Letters 2014年第12期12卷 48-51页

作者：王迪刘超王琼华周昕 School of Electronics and Information Engineering Sichuan University State Key Laboratory of Fundamental Science on Synthetic Vision Sichuan University

In this letter, we propose a voltage-controlled optical filter based on electrowetting. The device is made of a transparent cubic cell filled with two immiscible liquids having three indium tin oxide electrodes fabricated on the bottom substrate of the cell. A conductive droplet carrying a color filter is placed on the ITO electrode and the surrounding liquid is density-matched silicone oil. Under zero bias, the droplet is placed in the middle of tile substrate and white light passes through the filter and we can see red light on the screen. When a voltage is applied to the device, the filter moves with the liquid based on electrowetting effect, we can see the white light on the screen. Due to the movement of the liqnid, our device functions as an optical switcher. The switch trine of the device is -70 ms. The proposed device has a wide application in optical communication. electronic display, and optical switch.

关键词： Display devices Drops Electric switches Electrodes Liquids matched filters Optical filters Silicones Tin oxides Wetting

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