Abstract: Designs and implements an embedded multimedia player on Samsung S3C6410 platform; this player can support both hardware and software decoding using its built-in decoding interfaces and FFmpeg, which can decode multiple content formats including MPEG4, H.263, H.264 and VC1. Also, a novel model is proposed to gain better synchronization effect. The system architecture and results of preliminary performance experiments are presented.
Abstract: The alignment behaviors of polyatomic molecules under femtosecond laser pulses are experimentally and theoretically investigated. We observe the field-free alignment in C2H2 and CO2 molecules with High-Order Harmonic Generation (HHG) and discuss the evolution of the molecular rotational wave-packet with different laser parameters and ionization potentials. The results show that the molecular alignment degree depends not only on the laser parameters, but also on the molecular ionization potential. Finally we suggest the optimal aligning laser intensity to maximize the alignment degree for practical application.
Abstract: This article in view of the firing range and speed of ballistic test parameters, follow the "virtual instrument" thought to design a multi-function weapon test system, establishing a uniform platform development and complete Doppler radar speed module, meet a variety of ballistic speed needs. In the system, we realize intelligent control, real time collection of signal in time and frequency domain, result display at the same time and data analyze, Based on hardware realize, system realize testing of chamber volume.
Abstract: Online testing system based on frequency response analysis is proposed for the deformation of transformer winding. The structure of testing system, the selection of sweep sequence and computer diagram of data acquisition system are developed in the course of design. In the process of analysis, the concept of correlation coefficient is introduced to judge the relationship between the deformation extent and correlation coefficient. With the proposed method, the location of deformation can be determined. The testing curves demonstrate the effectiveness of the presented system.
Abstract: Structures of liquid-fuel injection in supersonic crossflow is studied experimentally. Schemes of flush-wall injector and aviation kerosene are selected. The conditions of the supersonic freestream are kept constant (total pressure is 0.5MPa, total temperature is 500K and Mach number is 2) and the diameter of the injector is fixed as 0.5mm, while seven scenarios of injection angle and three scenarios of injection driven pressure are discussed. Both methods of schlieren and planar laser induced fluorescence (PLIF) techniques are implemented to obtain the visual images of the liquid-fuel injection. The penetration height of fuel is analyzed quantitatively with the aid of Photoshop and Origin. The results serve not only the future computational simulation but also combined scheme of flush-wall injector and other combustor configurations.
Abstract: The received echo signals from different targets are considered as coherent in the MIMO radar. In order to improve the performance of direction estimation of multiple targets in lower SNR for MIMO radar, a new algorithm termed Transmission and Receiver Double Smoothing (TRDS) is proposed. Compared with the Transmission Diversity Smoothing algorithm, TRDS can deal with more targets in lower SNR with higher resolution. The theoretical analysis and simulation results show the proposed method is effective.
Abstract: A novel method employing Multi-Stage Wiener Filter (MSWF) and polynomial rooting is proposed for the one-dimensional angle estimation of MIMO radar. In this algorithm, the signal subspace is obtained using MSWF, which avoids the known expected signal, the estimation of the virtual data autocorrelation matrix and eigen-decomposition. Then, a polynomial rooting is adopted to realize angle estimation. The effectiveness of the proposed method is verified by numerical examples.
Abstract: In the temperature measurement system of distributed optical fiber based on Raman back-scattering, the temperature measurement depends on a series of laser pulses in the optical fiber, which produces anti-stokes and stokes lights of Raman back-scattering at various points. By using the ratio of them, the measurement of temperature field space can be realized. But the signals that can be gained are quite weak in practice, and there are interferences of noises and external signals, therefore APD is selected (Avalance Photodiode) to amplify the weak signals. Because the gain characteristics of APD are vulnerable to the influences of temperature and bias voltage, so in this paper the experiments were carried on about the effects of temperature, bias voltage, incident power etc. on APD, and a substantive discussion was discussed.
Abstract: A miniature ultra-wideband (UWB) bandpass filter using three-quarters wavelength resonators is presented in this paper. Direct-connected feed method is employed between the input/output ports and the resonators in order to overcome the shortcomings due to the gap-coupled feed method and produce two transmission zeros in the lower and upper stopbands. On the other hand, two quarter-wavelength matching transmission lines are introduced to the input/output ports to improve the reflection loss characteristic in the passband of the filter. In addition, the resonators are folded to be open ring structures, which are more miniaturized than the conventional linear structure. As a consequence, the filter is compact in size and exhibits good performance. The filter is successfully realized in theory and verified by full wave EM simulation, and simulated frequency response results show that the fabricated filter has an insertion loss of better than 1dB in the passband and two rejections of greater than 25dB in most of the stopbands.
Abstract: In this paper, an optimal design method for a CCD driving signal is proposed. Strict phase alignment of CCD driving signals is achieved. Through the analysis of FLEX 10K internal resources, the CCD driving pin voltage overshoots are eliminated on the basis of meeting the phase relationship. The experimental results show that the requirements for the phase of the CCD driving signals are satisfied, and the voltages on CCD pins become stabile. Therefore, CCD can be protected from damage.