电力电子系统若干数字控制技术的探讨（上）

与通常的采样系统相比,基于实时数字控制的电力电子装置或系统具有自身的一些特点。据此,在控制系统建模、控制方法设计等问题上已有一些有效的方法,也有一些新的技术动向。文中试图总结这些成果及其特点,以期对相关技术的研发有所帮助。     

数字电视用户接收系统中常见故障及处理方法

本文简要介绍有线数字电视用户室内接收系统中机顶盒及智能卡常见的故障、故障原因及排除方法。     

DSP技术在软件无线电系统中的应用研究

介绍了软件无线电的基本概念，讨论了软件无线电系统实现的关键技术，提出了一种基于DSP处理的软件无线电系统模型及实验平台实现方法。     

Robust image hash function using local color features

Conventional image hash functions only exploit luminance components of color images to generate robust hashes and then lead to limited discriminative capacities. In this paper, we propose a robust image hash function for color images, which takes all components of color images into account and achieves good discrimination. Firstly, the proposed hash function re-scales the input image to a fixed size. Secondly, it extracts local color features by converting the RGB color image into HSI and YCbCr color spaces and calculating the block mean and variance from each component of the HSI and YCbCr representations. Finally, it takes the Euclidian distances between the block features and a reference feature as hash values. Experiments are conducted to validate the efficiency of our hash function. Receiver operating characteristics (ROC) curve comparisons with two existing algorithms demonstrate that our hash function outperforms the assessed algorithms in classification performances between perceptual robustness and discriminative capability.     

基于VHDL语言的数字电路测试码自动生成

本文提出了一种新的基于VHDL语言的组合数字电路测试码自动生成方法。在VHDL语言描述组合数字电路的基础上,建一VHDL语言的编译器,并输入为描述被测电路的VHDL语言,输出结果为描述被测电路功能的一系列逻辑表达式。针对这些逻辑表达式,本文详细地介绍了一种能直接产生电路测试码的算法。     

基于数字锁相的雷达频率合成器的研究

在分析常规移频反馈数字锁相频率合成器相位噪声的基础上,提出了高频标置于环外、双反馈及倍相反馈等低相噪数字锁相频率合成技术,进行了比较详细的理论分析和讨论,给出了研究结果。     

一种按钮式数字电位器在视频数据混合器中的应用

介绍了按钮式非易失性数字电位器X9511的结构原理及特点,设计了它在收费站视频数据混合器（VDM）中应用的电路。该电路充分利用了X9511精度高、调节方便、性能稳定等优点,能够准确方便地调节视频图像上叠加字符的亮度及阴影的深度。     

日本对市话电缆承载数字传输能力的调查

介绍了模拟和数字通信回路兼收的市话电缆内线对间的串音特性,日本NTT公司对市话电缆承载数字传输能力的调查测试情况,并作了分析。     

The development of an open-network digital circuit multiplication equipment system

This paper discusses the systematization effort undertaken to generate an equipment specification of an extremely detailed and new nature for DCMEs in accordance with the INTELSAT specification IESS-501. The main areas of importance addressed are additional to what has already been defined within the IESS-501. A discussion of important aspects when introducing DCME into actual network conditions is also contained and results based on simulations of performance under simulated network environments are included.     

Increasing inequalities in what we do online: A longitudinal cross sectional analysis of Internet activities among the Dutch population (2010 to 2013) over gender,age, education,and income

We investigate types of Internet activities among a representative sample of the Dutch population from 2010 to 2013. We examined usage patterns of seven types of Internet activities (i.e., information, news, personal development, commercial transaction, social interaction, leisure, and gaming) and related these patterns with gender, age, education, and income. Activities related to news, personal development, commercial transaction, and social interaction increased in popularity. For most capital enhancing activities, men, younger people, higher educated people, and people with higher than average incomes were prominent. These observations, however, are subject to change. The Internet seems to provide increasingly more capital-enhancing opportunities for those with higher education and income, which would accordingly reinforce their already strong positions in society.