一种声纳信号模拟器算法及工程实现

本文首先给出了一种声纳信号模拟器的信号与噪声产生的算法。目标回波信号的产生采用复包络-调制法。噪声的产生利用白噪声激励AR滤波器来实现,分别讨论了复数AR滤波法和实数AR滤波法两种可能的实现途径,并分析了各自优缺点。在此基础上,给出了信号与噪声产生的硬件框图,并分析了其中的关键技术问题(均匀分布白噪声的获取、多路互不相关的噪声获取等)。最后给出了该声纳信号模拟器总体硬件框图和软件框图,并对该模拟器的运行结果进行了分析和检验。     

单端输出的机顶盒开关电源设计

在介绍了TOP Switch芯片的原理及特点的基础上．使用该芯片并通过对开关电源关键部件高频开关变压器中相关参数的计算设汁出了一种单端输出的机顶盒开关电源．给出了该电源在使用时的相关技术指标．为TOP Switch芯片在开关电源中的应用提供了理论和实验依据．     

Emotional modulation of cognitive control: Approach–withdrawal states double-dissociate spatial from verbal two-back task performance.

Emotional states might selectively modulate components of cognitive control. To test this hypothesis, the author randomly assigned 152 undergraduates (equal numbers of men and women) to watch short videos intended to induce emotional states (approach, neutral, or withdrawal). Each video was followed by a computerized 2-back working memory task (spatial or verbal, equated for difficulty and appearance). Spatial 2-back performance was enhanced by a withdrawal state and impaired by an approach state; the opposite pattern held for verbal performance. The double dissociation held more strongly for participants who made more errors than average across conditions. The results suggest that approach–withdrawal states can have selective influences on components of cognitive control, possibly on a hemispheric basis. They support and extend several frameworks for conceptualizing emotion–cognition interactions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

外调制器光调制指数的设计

利用信号与噪声自相关函数，研究了M－Z和MQW－EA两类调制器的非线性失真，分析了影响模拟光有线电视CATV系统中光调制指数的因素，在保证载噪比CNR指标的前提下，设计了光调制指数。     

Operation Mode on Pulse Modulation in Atmospheric Radio Frequency Glow Discharges

The discharge operation regime of pulse modulated atmospheric radio frequency(RF) glow discharge in helium is investigated on the duty cycle and frequency of modulation pulses.The characteristics of radio frequency discharge burst in terms of breakdown voltage, alpha(α)-gamma(γ) mode transition voltage and current are demonstrated by the discharge current voltage characteristics. The minimum breakdown voltage of RF discharge burst was obtained at the duty cycle of 20% and frequency of 400 k Hz, respectively. The α-γ mode transition of RF discharge burst occurs at higher voltage and current by reducing the duty cycle and elevating the modulation frequency before the RF discharge burst evolving into the ignition phase, in which the RF discharge burst can operate stably in the γ mode. It proposes that the intensity and stability of RF discharge burst can be improved by manipulating the duty cycle and modulation frequency in pulse modulated atmospheric RF glow discharge.     

具有抗杂散光干扰功能的光电光泽度计

本文介绍了一种具有抗杂散光干扰功能的光电光泽度计电路设计和工作原理.本设计采用了1kHz激光调制光源、二阶高通滤波电路等抗干扰措施.实测显示,在测试光泽度为100的样品时,用40W白炽灯、手电筒模拟干扰光对测光传感器近距离直接照射,输出示值变化小于1.5%,达到了理想的抗杂散光干扰效果.     

超高压大功率直流输电系统的先进控制技术应用及发展

在总结直流输电系统常规控制策略的基础上,综合评述了近年来先进控制技术在高压直流输电HVDC(High-Voltage Direct-Current power transmission)控制及调制技术中的应用研究现状．介绍了当前各种控制研究所采用的技术路线和实现方式．重点分析了各种控制方法和控制策略的优点和不足．指出了HVDC控制研究中亟待解决的问题,如控制策略的综合评估,系统化多馈入交直流系统直流调制信号选取原则．具有自适应阻尼能力的HVDC小信号调制技术．具有鲁棒性的大信号调制技术．全局协调控制等。对可能的研究手段进行了探讨。     

基于空间矢量的电流型整流器的功率因数校正技术研究

在分析空间矢量调制技术(SVM)的基础上,实现了电流型整流器的电流空间矢量调制技术,并利用三相电压型整流器的二逻辑电压空间矢量调制实现了电流型整流器的三逻辑空间矢量调制,且获得了电流型整流器的单位功率因数.两种方法进行了仿真对比,得出一些有益的结论.     

基于DSP的光伏水泵变频调速系统

介绍一种基于DSP的光伏水泵变频控制系统.利用空间矢量PWM算法实现对光伏阵列母线电压动态补偿的功能,保证在光伏阵列工作电压大范围变化条件下,变频驱动电机满足恒磁通调速控制.同时结合光伏水泵系统的工作特点,提出了一种简单实用的光伏阵列最大功率点跟踪控制方式,稳定可靠地实现了系统的最大功率点跟踪控制.     

一种基于模糊逻辑的直接转矩控制算法

介绍了一种新颖的基于模糊逻辑的直接转矩控制算法,该算法利用电机转矩偏差和定子磁链偏差,运用模糊逻辑控制器动态地得到所期望的空间电压矢量,再结合空间矢量调制技术实现对异步电机的控制.该算法结构简单,可大大减小转矩脉动和磁链脉动.仿真结果证实了该算法的有效性.