数字电视进程中的机顶盒

随着数字音视频压缩技术的迅速发展与实用化,发生了一场消费电子产品从模拟技术转向数字技术的革命。1995年,美国高级电视制式委员会(ATSC)以ADTV大联盟开发的制式为基础,向联邦通信委员会(FCC)提出了美国数字电视标准的建议。1996年12     

数字电视机顶盒中前端

数字电视机顶盒中的前端对于信源解码板能否正常解码起到了至关重要的作用.在简要讨论DVB-C标准的信道传输的基本原理的基础上,从硬件结构、软件设计等方面介绍数字电视机顶盒中接收有线射频信号的前端的设计与实现.     

数字电视浪潮推动机顶盒产业快速发展

近年来,数字电视服务在全球范围内得到大力推广,各国都制定了基于本国发展现状的数字化转换时间表,广播电视数字化的浪潮不可逆转。伴随着整个电视产业的升级,从制播、传输到接收的多数设备都将更新换代。从终端的接收方式来看,由于数字电视一体机标准不统一,市场推广受阻,而机顶盒加电视机的组合方案则形式灵活,成为目前数字电视接收的主要方式。     

IPTV与IP机顶盒技术

一、IPTV技术简介 IPTV是一种利用宽带网或有线HFC网络集互联网、多媒体、通讯等多种技术于一体，以家用电视机／计算机作为主要显示终端向家庭用户提供包括数字电视在内的多种交互式视颁节目服务的崭新技术。IPTV技术中非常鲜明的特点是可以实现媒体服务者和消费者互动，能根据用户的选择提供内容广泛的多媒体服务，使用户在得到高质量数字多媒体服务的同时，能够自由地选择视频节目。简单地说，IPTV技术的主要特点有：     

数字(高清晰度)电视机顶盒音频系统研制

适用于地面、电缆传输系统的数字高清晰度电视接收机顶盒，正在由研制阶段走向规模化生产。本文介绍了所研制的机顶盒中音频系统结构、关键芯片及配套软件。实验证明本系统性能良好。     

中国机顶盒市场持续增长

2008年,中国数字电视产业特别是有线数字电视产业保持了快速发展的势头,数字电视机顶盒市场与数字电视整体转换同步发展,市场规模不断增长。2008年前三季度中国机顶盒市场销量迎来井喷,赛迪顾问的调研数据显示,前三季度中国市场共销售机顶盒1666．7万台,同比增长了83．4％。     

兼容性机顶盒系统

文中介绍基于单片VLSI芯片、可以同时接收卫星和有线电视节目信号的机顶盒实现方案.既提供机顶盒核心硬件部分的总体框图和功能模块的实现方法,又阐明软件设计的重点.所研制的机顶盒操作简单,工作性能稳定,成本较低,有很好的市场前景.     

中国机顶盒市场持续增长

2008年,中国数字电视产业特别是有线数字电视产业保持了快速发展的势头,数字电视机顶盒市场与数字电视整体转换同步发展,市场规模不断增长。2008年前三季度中国机顶盒市场销量迎来井喷,赛迪顾问的调研数据显示,前三季度中国市场共销售机顶     

数字电视机顶盒PSI/SI信息接收和存储方案设计

设计了一种改进型PSI/SI信息接收和存储方案。在接收过程中,通过改进section拼接技术实现section随机且无丢失的快速接收和拼接;在存储过程中,通过三级结构实现PSI/SI同级别信息的联合存储,方便了PSI/SI信息的查询。     

Microwave bytes- Squaring Up

This assumption seems to underpin not just microstrip design, but really the whole of transmission line theory as we know it, certainly as we were always taught it. The author assumes that the cross-sectional dimensions of any transmission line are negligible, not just in comparison to its length, but essentially to a wavelength as well. Transmission line theory only applies when the line is "long and thin." In conventional practice, this means it is actually quite restricted in the range of characteristic impedances that is used. The restriction applies as well, of course, to the height or substrate thickness, but in this case our basic electromagnetic (EM) theory is at least able to stipulate and even quantify the hazards of allowing higher-order waveguide modes to propagate     

Annoyances in Growing Up

Annoyances in growing up seem to be unavoidable. Many problems still face the Chinese power industry just climbing onto a new level of 600-GW installed capacity, It has to search practicable solutions for problems with the significant themes including structure optimization, efficiency improvement and environment protection.     

变电站综自改造中合闸保持回路浅析

变电站综自改造后,由于新旧设备之间的配合不当,时常发生故障,通过对问题的分析,解决了变电站综合自动化设备与传统电磁操动机构在电气方面的配合问题,提高了系统稳定性。     

变压器合闸时的励磁涌流

主要讨论了励磁涌流的产生和其对变压器的影响。     

Power Systems in Close Proximity to Pipelines

In recent years, a trend has developed toward building energy corridors which better utilize land resources. Due to the adverse environmental impacts of building electrical power lines by utility companies and the installation of pipelines by the petrochemical industry, many governmental entities are requiring that electric power lines and underground pipelines use the same transmission (energy) corridor. The energy corridor, by design, is used to minimize the land requirements for transmitting energy?whether by electrical transmission lines or through pipelines. The energy corridor does not necessarily minimize the lengths of transmission lines but, conversely, may require longer lines to utilize the land resources better by paralleling transmission systems. The electric power companies have utilized this practice in the past with electrical corridors and are being pressured to make every effort to parallel electric lines in the future on these same corridors. The effect of paralleling electric circuits has been long understood by the electrical engineer. Induced currents and voltages occur between the electrical circuits and may cause relaying, communications, and safety problems. Proper engineering has led to solutions to most of these problems. A problem has developed with the addition of pipelines to the electrical corridors or, conversely, electrical lines to the pipeline corridors. The problem is that the pipeline has become part of the electrical circuit due to electrostatic and electromagnetic coupling. This coupling may cause induced currents and voltages to exist on the pipeline. The pipeline is addressed as an electrical circuit.     

市场化的配电自动化

由于经济的加速发展,近期我国电力市场出现了供不应求的情况,成了制约国民经济持续快速发展的一大阻碍。配电在电力系统中处于重要的地位,由于历史的原因我国电力系统长期以来形成了“重发、轻供、不管用”的局面。随着经济建设的发展和人们生活水平的提高,对供电质量和供电可靠性提出了更高的要求,要进一步提高配电网的可靠性,必须全面实现高水平的配电网自动化。: 请谈谈目前我国配电自动化的现状与存在的问题。王明俊:电力系统发电、输电、配电同步完成的特点,要求各个环节的发展应有一个合理的比例关系,一些发达国家这个比例是1∶0.34～…     

中国LED照明降温还是升温

环保、节能、耐用几乎成了LED的代名词,然而LED并非十全十美,它也存在自身的弱点。也存在着技术瓶颈。当下,我们应该怎样看待LED及LED产业,是迅速进入。还是观望等待？