本地OTN承载业务探讨与应用浅析

在阐述OTN设备技术特点的基础上,与其他传送方式在经济性及便利性等方面进行了比较,给出了本地OTN承载业务的建议,并以案例论述了本地OTN在工程中的具体应用。     

影响地面雷达测高精度的因素

针对某型三坐标地面雷达,对影响地面雷达测高精度的主要因素进行了分析。基于阵地地形、电磁环境、杂波环境、大气环境和人为导致的系统异常等因素,分析了地面雷达测高误差产生的原因,评估了多种因素对测高精度的影响程度,提出了在实际应用中规避影响因素以改善地面雷达测高精度的建议。     

基于双目视觉的光束法平差新算法

针对双目视觉中两摄像机的固定约束关系,提出了基于双目视觉的光束法平差新算法.对传统光束法平差法方程构造过程进行了改进,使每次迭代过程中只需对拍摄的两幅图像中一个摄像机的外参数进行优化,更好地将两个摄像机绑定为一个摄像机,使优化精度更高;新算法中,法化矩阵的维数比传统算法降低了1/2,所以每次迭代计算所需要的时间也会减少...     

Information theoretic learning with adaptive kernels

This paper presents an online algorithm for adapting the kernel width that is a free parameter in information theoretic cost functions using Renyi's entropy. This kernel computes the interactions between the error samples and essentially controls the nature of the performance surface over which the parameters of the system adapt. Since the error in an adaptive system is non-stationary during training, a fixed value of the kernel width may affect the adaptation dynamics and even compromise the location of the global optimum in parameter space. The proposed online algorithm for adapting the kernel width is derived from first principles and minimizes the Kullback-Leibler divergence between the estimated error density and the true density. We characterize the performance of this novel approach with simulations of linear and nonlinear systems training, using the minimum error entropy criterion with the proposed adaptive kernel algorithm. We conclude that adapting the kernel width improves the rate of convergence of the parameters, and decouples the convergence rate and misadjustment of the filter weights.     

可自适应调节带宽的新型非线性二阶锁相环

大捕获带宽的同步给传统二阶锁相环带来了巨大挑战。文中针对传统锁相环捕获带宽与抑制噪声能力两者之间的矛盾,提出一种耦合非线性环节的新型二阶锁相环,利用非线性模块自适应调整环路噪声带宽。输入输出相位误差较大时利用较大的带宽迅速减小频偏;当相位误差由于环路控制作用而减小时,利用较小的带宽抑制噪声以提高跟踪精度。仿真结果表明,非线性二阶锁相环跟踪速度显著提高,且相比传统二阶锁相环,捕获带宽从4 kHz最大提高到18.8 kHz。     

VLSI Implementation of Forward Error Control Technique for ATM Networks

In asynchronous transfer mode (ATM) networks, fixed length cells of 53 bytes are transmitted. A cell may be discarded during transmission due to buffer overflow or a detection of errors. Cell discarding seriously degrades transmission quality. The quality degradation can be reduced by employing efficient forward error control (FEC) to recover discarded cells. In this paper, we present the design and implementation of decoding equipment for FEC in ATM networks based on a single parity check (SPC) product code using very‐large‐scale integration (VLSI) technology. FEC allows the destination to reconstruct missing data cells by using redundant parity cells that the source adds to each block of data cells. The functionality of the design has been tested using the Model Sim 5.7cXE Simulation Package. The design has been implemented for a 5 ° 5 matrix of data cells in a Virtex‐E XCV 3200E FG1156 device. The simulation and synthesis results show that the decoding function can be completed in 81 clock cycles with an optimum clock of 56.8 MHz. A test bench was written to study the performance of the decoder, and the results are presented.     

偏振正交误差对偏振光导航定位系统测量精度的影响

偏振正交误差是影响四通道时分复用大气偏振检测系统精度的主要因素。通过建立检偏器阵列偏振正交误差对偏振光导航系统定位精度的影响模型,分析了该误差对大气偏振测量精度与导航定位精度的影响,并进行了实验验证。理论与实验结果表明,降低检偏器阵列偏振正交误差,可以显著提高系统大气偏振测量精度与导航定位精度。当检偏器阵列偏振正交误差无法消除时,调整定位初始角可以明显提高系统测量精度与导航定位精度。     

基于针孔阵列的多光束共焦三维测量系统

提出了一种基于 5 0 0× 5 0 0的针孔阵列的多光束共焦三维测量系统 ,该系统具有测量视场大 ,测量速度快 ,系统结构简单等特点     

基于TL494的直流变换器

文章介绍了开关电源的基本原理,DC/DC变换主电路分类,对开关电源的控制方式进行了比较,给出了专用集成控制器的优点。给出了专用集成控制器TL494的内部结构、管脚功能,详细分析了其工作原理、应用和优点,列举了TL494的应用实例。设计了一款由TL494控制的Buck型开关电源,给出了所用元器件,对整个电路工作原理进行了分析,分析了其产生PWM信号的原理,接收反馈实现稳压的原理及实现过流保护原理,测试其关键点的工作波形,并对此电路做了些改进,基于此对TL494进行了测试,该电路是TL494的典型应用,可以体现出TL494的大部分功能,电路具有采用元件少、性能稳定、效率高的优点。     

基于误差控制的SAR投影失真快速校正算法

随着合成孔径雷达(SAR)技术的发展和广泛应用,为了更准确反映场景信息,几何校正成为SAR图像处理过程中的重要内容.文中根据机载SAR成像机理,分析了引起机载SAR图像几何投影失真的原因,并估算出其失真量,针对传统的非线性校正方法,提出了一种快速高效的基于误差控制的动态分段线性校正算法.该算法在保证SAR图像校正质量的前提下,通过控制SAR图像校正误差,用线性处理取代了非线性逐点运算,使得校正算法的计算复杂度大大降低.文中还从理论上推导出最佳的分段校正长度计算方法,可校正过程中动态调整分段长度,保证校正质量和运算效率.最后通过仿真试验验证了该文法的有效性和实用性.