构造嵌入式Linux系统

文中首先介绍了嵌入式Linux系统的优点及其广泛应用.然后针对构造一个Linux嵌入式操作系统所面临的问题作了具体深入的分析.这些问题具体包括如何精简内核以及系统启动过程的细致分析,如何为硬件编写驱动程序.     

AlGaN-GaN double-channel HEMTs

We present the design, fabrication, and characterization of AlGaN-GaN double-channel HEMTs. Two carrier channels are formed in an AlGaN-GaN-AlGaN-GaN multilayer structure grown on a sapphire substrate. Polarization field in the lower AlGaN layer fosters formation of a second carrier channel at the lower AlGaN-GaN interface, without creating any parasitic conduction path in the AlGaN barrier layer. Unambiguous double-channel behaviors are observed at both dc and RF. Bias dependent RF small-signal characterization and parameter extraction were performed. Gain compression at a high current level was attributed to electron velocity degradation induced by interface scattering. Dynamic IV measurement was carried out to analyze large-signal behaviors of the double-channel high-electron mobility transistors. It was found that current collapse mainly occurs in the channel closer to device surface, while the lower channel suffers minimal current collapse, suggesting that trapping/detrapping of surface states is mainly responsible for current collapse. This argument is supported by RF large-signal measurement results.     

Efficient Hardware Implementation Architectures for Long Integer Modular Multiplication over General Solinas Prime

Journal of Signal Processing Systems - Modular multiplication of long integers is a key component of elliptic curve cryptography and homomorphic encryption. The multiplication complexity can be...     

Method of multi-target tracking in wide area surveillance airborne radar system basing on clustering analysis

This paper proposed a robust method based on the definition of Mahalanobis distance to track ground moving target. The feature and the geometry of airborne ground moving target tracking systems are studied at first. Based on this feature, the assignment relation of time-nearby target is calculated via Mahalanobis distance, and then the corresponding transformation formula is deduced. The simulation results show the correctness and effectiveness of the proposed method.     

FPGA器件的开发平台与MATLAB接口仿真

针对FPGA设计软件Quartusll的仿真功能在可视性方面的局限性给程序早期仿真来的不便,本文提出一种将FPGA开发平台与MATLAB接口仿真的方法。该方法利用Matlab软件的计算功能与可视化仿真功能,大大地方便设计人员对设计项目进行早期修正。[编者按]     

最小均方误差检测器对扩频系统中窄带干扰的抑制性能分析

本文首先说明当码元间隔内的码片数目与扩频序列周期相等时,直接序列扩频(DSSS)系统中最小均方误差(MMSE)意义下的最优滤波器也是最小误码率意义下的最优滤波器,因而能很好地抑制大多数干扰样式。本文具体分析了最小均方误差检测器对音频干扰以及自回归干扰的抑制性能,给出了详细的推导过程以及结论。     

SMS4密码算法高速引擎实现

SMS4是国内公布的无线局域网分组密码算法,文章在分析该算法特点的基础上,介绍了一种单轮内流水的高速引擎实现结构.通过配置多个引擎进行二次流水或并行处理,可以灵活调整输出性能和硬件开销,以适应不同应用的需求.在FPGA的对比测试中,相同输出性能下,具有比32轮流水线结构更小的硬件开销.而且在单引擎应用时,SMS4加/解密系统可以非常容易的在低端的Spartan Ⅱ XC2S50 FPGA上实现.     

输油气管道非开挖弱磁检测

针对长输油气管道随着服役时间增长出现腐蚀泄露甚至安全问题,提出埋地管道非开挖弱磁检测技术,能实现埋地管道在役非开挖检测。简述了弱磁检测技术和磁梯度法的基本原理以及基于统计学原理的缺陷判定方法,并对埋地管道作了失效分析。利用弱磁检测仪器对有缺陷的埋地管道作了试验,验证了该检测技术的可行性。结果表明,该检测方法对埋地管道腐蚀检测有很好的检测效果和检出率,能实现埋地管道在役时的非开挖检测以及腐蚀缺陷的二维成像。     

短波智能天线阵信号提取的一种实用方法

介绍一种提取噪声中信号的方法。首先从理论上分析同相叠加从噪声中提取信号的可行性,并给出一种具体的设计方案,最后给出计算机模拟仿真结果,来说明所介绍方法的可行性。