数字信号处理课程虚拟实验室设计

本文设计了一个基于校园网的数字信号处理课程虚拟实验室,该实验室可以通过远程控制为各实验设备单独供电,并通过开关矩阵灵活组合连接实验设备。运行表明虚拟实验室构造简便,结果正确,可以为学生提供一个方便的开放实验室。     

节能技术在建筑设备工程中的应用与探讨

伴随着我国经济高速发展、产业结构调整及世界性能源紧缺的大背景下,建筑节能已经成为建筑行业必须面对、考虑和解决的问题。本文从建筑设备工程所涉及的给排水管网系统的减压节流、水泵的变频控制,空气调节系统节能技术,电气系统节能技术等几方面进行阐述。节能技术在建筑设备工程中的应用与开展,有着重大的社会效益、经济效益和业主效益,同时也是社会和建筑行业发展的必然。     

关于制约电视数字化发展的几点思考

数字电视是指节目从摄制、编辑、播出、发射到接收的整个过程都是采用数字化技术实现的。数字电视与现在的模拟电视相比具有很多优势,发展数字电视已是信息时代的必然发展方向和趋势。     

Causality effects in return volatility measures with random times

We provide a structural approach to identify instantaneous causality effects between durations and stock price volatility. So far, in the literature, instantaneous causality effects have either been excluded or cannot be identified separately from Granger type causality effects. By giving explicit moment conditions for observed returns over (random) duration intervals, we are able to identify an instantaneous causality effect. The documented causality effect has significant impact on inference for tick-by-tick data. We find that instantaneous volatility forecasts for, e.g., IBM stock returns must be decreased by as much as 40% when not having seen the next quote change before its (conditionally) median time. Also, instantaneous volatilities are found to be much higher than indicated by standard volatility assessment procedures using tick-by-tick data. For IBM, a naive assessment of spot volatility based on observed returns between quote changes would only account for 60% of the actual volatility. For less liquidly traded stocks at NYSE this effect is even stronger.     

高炮随动系统自动测试中正弦机发送频率的确定

在某型高炮随动系统测试中,正弦机的发送频率直接影响着输出信号的平滑度,从而会影响测试的精度。为了避免在正弦机运行过程中,计算耗用过多机时,在正弦机发送之前,先计算出每个位置信号、前馈信号的数值,存放于内存中。本文根据该正弦机信号的特点,分析了几种正弦机角位置信号发送频率方式的优缺点,确定了正弦机发送频率的方式。     

高等师范院校古代汉语教学语料库字频研究

对基于高等师范学校古代汉语教学的语料库相关数据结果做了定量分析,阐述了语料库的用字概况,提出了字区划分的标准,研制了分区字频表。     

《高频电子线路》课程教学中的几个重要环节

《高频电子线路》课程是工程电子、通信类专业的一门重要专业基础课程,该课程主要学习通信系统中构成发射机、接收机的单元电路。文章针对学生学习高频电路困难的现状进行分析,从而探讨了在教学中如何从五个方面使学生对该课程产生兴趣并以清晰地思路学好本课程。     

Re-examining online customer experience to include purchase frequency and perceived risk

This research examines the important emerging area of online customer experience (OCE) using data collected from an online survey of frequent and infrequent online shoppers. The study examines a model of antecedents for cognitive and affective experiential states and their influence on outcomes, such as online shopping satisfaction and repurchase intentions. The model also examines the relationships between perceived risk, trust, satisfaction and repurchase intentions. Theoretically, the study provides a broader understanding of OCE, through insights into two shopper segments identified as being important in e-retailing. For managers, the study highlights areas of OCE and their implications for ongoing management of the online channel.     

航天测控通信系统综合基带中频接收单元数字化方案

本文论述了利用DSP处理器和FPGA完成70MHz卫星下行信号的载波捕获与跟踪、多普勒提取、遥测和测距信号的解调，从而实现了中频接收的数字化、软件化、提高了系统的精度，大大缩小了系统的体积。     

基于TMS320VC5402的语音检测器

本文介绍的语音检测器以DSP芯片TMS320VC5402为核心，对短波电台接收到的信号进行分析和处理。数字语音信号采用串行输入／输出方式，语音检测算法则采用对语音信号进行降噪处理后，再进行短时平均幅度差和短时能量计算的方法。该语音检测器的电路简洁小巧，语音检测准确度高。