数字信道

Alternatively,one could allocate each channel a recurring segment of time over which to broadcast---this is know as time division multiplexing and is sometimes used in digital communication.

另一种方法是给每个信道分配重复的时间段，在这种时间段中进行广播，称为时分多路技术，有时用于数字通信中。

This paper mainly focuses on the research and realization of the channel receiving chip according with the DTV transmission draft in cable which we proposed.

本文主要针对我们提出的数字电视传输方案电缆模式下的信道接收芯片的设计和实现进行了研究。

By time-varying filtering, we realize the signal selectivity and interference suppression, especially for the signals with time-varying power spectrum. It is shown herein that conventional eigenstructure based methods are lower dimensional special case of the time-frequency subspace fitting method. The closed-form array response estimation algorithms for blind source separation in wireless communication is also developed in the dissertation by exploiting the data structure of second-order statistics of the array output in the presence of multipath. The proposed method achieves array response estimation with little constraint on signal property and propagation environment such as scatters or angular spread. Moreover, the array utilized here can be of arbitrary geometry and even uncalibrated. Since the closed-form solution is obtained, no misconvergency may occur and large amount of computation can be saved. The equivalent feed model and corresponding optimization designation are proposed to realize the downlink multi-user selective transmission. By coherent and non-coherent superposition of the electromagnetical field, multiple beams can be formed using a single array, so that each co-channel user signal is transmitted in each beam and will not interfered with each other. The proposed system scheme implements the digital beamforming and the channel allocation in the base band, therefore is suitable for the utilization of the radio software technology. The feasibility and effectiveness of the proposed model are proved by the RF experiment.

在窄带条件下，GSC－SSF方法还可以提高阵列的虚拟孔径，从而提高估计的性能；可以证明，Cyclic DOA 和SC-SSF方法可看作该方法的特例或近似； 3、提出了二维GSC－SSF方法和宽带谱相关DOA矩阵方法，利用信号的循环平稳特性解决了宽带条件下二维 DOA 估计问题，并具有阵元数少、计算量较小的特点； 4、提出了时频子空间拟合和宽带时频DOA估计算法，将联合时频分析的理论和方法引入到阵列信号的空间谱估计研究中，利用时变滤波实现信号选择性测向和干扰抑制，特别适合于谱时变信号；可以证明传统特征结构法可看作是时频子空间拟合方法的特例； 5、提出了多用户环境下阵列响应的估计方法——CARE方法，该方法对信号结构和传播参数（主要是散射源分布与角度散布）的约束较少，适用于各种几何结构的阵列甚至未校准的阵列，能够直接得到阵列响应的闭式解，因此计算量小、稳健性好，不存在收敛问题； 6、提出了针对多用户下行选择性发送的阵列等效激励模型、优化设计方法及其系统实现方案，通过空间场的相干叠加与非相干叠加使得单一阵列能够形成多个波束，并保证各波束内的用户信号各不相同且相互干扰最小；其系统方案具有在基带实现数字波束成形、信道分配并便于软件无线电实现的特点，其有效性已得到外场实测数据的证实。

In digital signal transmission systems, parallel transmission is the most efficient transmission technique at present for non-ideal channel. In which, orthogonally multiplexed QAM system and discrete multitone system are two typical systems.

在数字信号传输系统中，并行传输是目前最有效的一种抗信道失真传输技术，而正交复用QAM和离散多载波是两种并行传输系统典型的实现方式。

Focusing on three key issues of the efficiency of video transmission, reliability and friendship on nets, the paper conducts a deep analysis of the enhancement of the compression of video-coding layer based on H.264, the optimized assembly of the net matching layer and the ability to correct errors of the decoder and encoder. Take the package switch of IP Video information package as an example, the thesis focuses on the reflection process of the Internet RPT/UDP/IP acted on by H.264, illustrates the typica...

围绕视频传输要求高效、可靠和网络友好的三个焦点问题，深入研究H 。2 6 4标准编码层压缩性能的提升、网络适配层的无缝集成和编/解码器的容错性能；以基于包交换的IP视频信息包为例，重点分析H 。2 6 4对因特网RTP/UDP/IP协议的映射过程；阐述H 。2 6 4在视频移动通信、视频流服务、数字电视广播与存储领域的典型应用特点；指出H 。2 6 4对视频源压缩、信道有效利用、缓解视频传输瓶颈的影响和发展前景。

For high performance,concatenated coding is often used in the data communication system.

在数字通信系统中，为了保证通信的高质量，在信道中采用了各种编码来降低误码率。

The phone companies are obsoleting the 56 Kbps service in favor of the more modern ISDN BRI, which has two 64 Kbps circuits and one 16 Kbps packet service, part of which is used for signaling on the 64 Kbps channels.

电话公司们已经废弃56 Kbps这一称呼，改用现在的ISDN BRI，其中有两根64 Kbps数字电路和1根16 Kbps分组服务。16 Kbps电路中部分用于64 Kbps信道中的信令传输。

Because it getting higher compression than, gooder of IP and the network adaptability of channel not wirelesses, communicate and store the field to get more and more extensive application in the digital video .

因其更高的压缩比、更好的 IP 和无线网络信道的适应性，在数字视频通信和存储领域得到越来越广泛的应用。

Digital fountain is a packet oriented forward error correction technology for channels with erasures, which has obvious efficiency advantage in broadcast.

摘要数字喷泉是近年发展起来的一类基于删除信道、面向数据分组的前向纠错编码技术，在广播类传输中具有明显的效率优势。

This article is introduces the information hideaway technology the development present situation, therefore this article mainly aims at the information hideaway technology at present in each domain development present situation, mainly introduced in the application domain in the copyright protection and the privacy communication several kind of information hideaways technology, as well as the information hideaway technology the function which displays in information security each domain, but also has carried on the forecast to the information hideaway technology future prospect.

本文是介绍信息隐藏技术的发展现状，因此本文主要针对信息隐藏技术目前在各个领域中的发展现状，并且主要介绍应用领域中版权保护和保密通信中的几种信息隐藏技术，以及信息隐藏技术在信息安全的各个领域中所发挥的作用，还对信息隐藏技术的未来的前景进行了预测。关键词：信息隐藏，数据锁定，隐匿标记，数字水印，阈下信道，匿名连接

This brought fixed cost, but it also is meant at the same time use a source to won't make you singlehanded assume a problem.

这带来了一定的成本，但它同时也意味着使用开源不会让你独力承担问题。

He gained a small fortune in real estate.

他在房地产上发了一笔小财。