浅谈有线电视网的Cable Modem宽带接入技术

本文介绍了Cable Modem的主要技术及优势。     

宽带IP骨干网的DPT环网技术

自上个世纪90年代以来，Internet的发展汹涌澎湃，目前北美Internet骨干网上的IP业务量每6～9个月左右就翻一番，比名的CPU性能进展的摩尔定律(约18个月左右就翻一番)还要快2～3倍。同样，中国Internet的发展也是每6个月左右增长一倍，据中国互联网络信息中心统计，到上世纪末，我国Internet用户数为400万左右。因此，人们认识到随着IP业务量持续的呈指数形式的增长，宽带IP网络的建设会在未来的网络建设中起到决定性的作用。     

宽带网络建设的关键技术研究

在宽带网络建设中,存在着三个关键技术——宽带网络接入技术、宽带网络传输技术和宽带网络节点的存储处理技术。 1 宽带网络接入技术1.1 基于PSTN的接入技术 传统铜线接入技术,即借助于电话线路,采用各种先进的调制技术和编码技术来提高铜线的传输速率,主要包括如下几类: (1)DSL(Digital Subscriber Line)技术     

A Practical Tantalum Thin-Film Single-Sideband Demodulator Using RC Time-Varying and Active Networks

The thin-film circuit described in this paper is equivalent to a demodulator circuit containing an extremely selective filter ("sideband" filter). Such a filter would, in conventional form, require very high Q inductors or, as the Q requirement increases, the use of crystal or mechanical filters. At the frequency of operation of this circuit (1 MHz), demodulation with conventional filters would have to be accomplished in two or more stages so that the selectivity requirement can be decreased for each filter. Thin-film techniques restrict us to circuits using only resistors (R), capacitors (C), and added semiconductor devices (thin-film inductors are not considered here since their inductance values are too small). The current trend is to realize frequency selective networks (conventionally in LC form) as active RC networks. However, although the circuit described here incorporates such a network, the main selectivity requirement cannot be met by present-day active network techniques. The solution is found in the use of time-varying RC networks, i.e., by combining passive RC thin-film phase-shift networks with miniature transistors, used as electronic switches, in the form of so-called quadrature modulation circuits. The phase-shift networks, which in principle can be passive thin-film RC circuits, are in practice more easily realized as combinations of much simpler RC circuits with buffer amplifiers.     

True Broadband Technique for On-Chip-Series Connection of TWAs Using Differential Distributed Amplifiers

A new technique for series connection of monolithic broadband travelling wave amplifiers (TWAs) is presented, using differential distributed architectures. This technique is intrinsically broadband because no series capacitor is used, it starts operating at dc up to cut-off frequency. With a GaAs heterojunction bipolar transistor monolithic microwave integrated circuit process, two on-chip-series coupled 18 dB gain and 23 GHz cut-off frequency TWAs are realized. Our approach avoids packaging steps and hybrid components. This is a very promising result for monolithic high-gain broadband amplifiers.     

A Broadband CPW-to-Microstrip Modes Coupling Technique

A broadband vertical transition from coplanar waveguide (CPW)-to-microstrip modes is presented. The transition has a double resonance and can be tuned for very wide-band operation. The CPW-to-microstrip modes coupling technique is useful for the vertical integration of multi-layer millimeter-wave circuits, packaging and antenna feeding networks. A vertical transition has been fabricated on 100 μm silicon substrate for operation at W-band frequencies and shows less than 0.3 dB of insertion loss and better than 12 dB of return loss from 75 to 110 GHz. A 94 GHz CPW-fed microstrip antenna showing a 10-dB bandwidth of about 30 % has been built using the same transition technique.     

Lazy Flooding: A New Technique for Information Dissemination in Distributed Network Systems

Flooding is a commonly used technique for network resource and topology information dissemination in the data communication networks. However, due to the well-known N-squared problem it causes network delay in response or even congestion. We propose a new flooding technique, called Lazy Flooding; it floods only when links reach a certain status. It significantly cuts down the number of floods and thus improves the data communication network response time. On the other hand, it has negligible effect on the network performance due to the selected flooding     

宽带有线电视网络设计

广播电视正向网络化、数字化和多功能化发展,其网络正处于一个大发展时期。本文探讨宽带多媒体通信网的解决方案,介绍一种宽带多媒体通信网技术及其应用。     

GPON--下一代宽带光接入网

PON是一种新兴的覆盖最后一公里的宽带接入光纤技术。随着PON的发展,应用于PON上的技术也层出不穷,APON、BPON、EPON以及最近出现的GPON技术都进一步推动了宽带光接入网的发展。主要介绍了GPON的设计目标以及GPON系统的关键组成部分。     

漳州广电宽带城域网骨干传输技术的选择

本介绍了DPT、MSTP、“一机双平面”骨干网传输技术。着重说明了选择华为公司“一机双平面”技术的依据。     

UAS在宽带网络中的应用

依次介绍了在网络建设中引入UAS的必要性,ZXE10-UAS的功能,以及ZXE10-UAS的组网方案。     

A Multirate Switching Network for Broadband Channels

A broadband ISDN switching network model is presented, switching the channel types H2, H3, and H4 envisaged by the CCITT. The synchronous time division multiplex technique is applied. The switching network operates at the basic bit rate of the H2-channel; H3and H4-connections are established via multichannel connections of up to four basic channels. H2-connections which are part of one H3- or H4-connection always have to use common interconnection links. This is a favorable solution to keep digit sequence integrity for multichannel connections, but influences blocking characteristics of the switching network. The implementation of an optimal path selection method plays a fundamental role. In such a multichannel switching network, blocking probabilities for H2-, H3-, and H4-connections must be distinguished. They do not only depend on the total offered load, but also on the proportions of H2-, H3-, and H4-connections (traffic mix). The simulation results presented in this paper prove that multirate switching via multichannel connections is feasible for the broadband channel types H2, H3, and H4, and that the proposed switching network has a sufficiently high traffic capacity whatever the traffic mix may be.     

宽带高速网络电台灵敏度测试方法研究

提出了一种宽带高速网络电台灵敏度测试的方法。首先分析了现有测试方法的缺陷,然后分析了采用复杂数字调制的宽带高速网络电台的基本原理,提出了利用仿真中产生的波形文件和信道模型,利用矢量信号源提供的IQ调制、衰落,进行灵敏度测试。实验表明该测试方法可行,并具有一定的通用性。     

宽带广电网的异步转移模式

异步转移模式(ATM)是继时分交换和分组交换之后的将统计复用与时分交换融为一体的新一代信息转换方式.ATM技术通过采用53字节定长信元和不同的虚通道∕虚通路进行负载的传送,具有包括语音、视频和数据在内的综合业务传输能力,市场驱动力强大.     

Distributed RC problem in the buried collector CID

The distributed resistance-capacitance (RC) problem arising in the buried collector of the three-terminal charge injection device is treated analytically. The results are applied to several signal detection methods. It is found that the minimum time required to detect 99 percent of the signal is approximately 2τ wheretau = rho_{s}CW^{2}with ρsthe collector sheet resistance,Cthe junction capacitance per unit area andWthe collector length. The calculated results are applicable to signal transients that occur in long polysilicon and other transparent electrodes.     

A New Technique for Measuring FM & TV Antenna Systems

Described here is a measuring system using a computer controlled network analyzer that allows observation of FM and TV broadcast antenna systems. Impedance measurement may be made at any point in a broadcast antenna system where access is possible. Most notably, the VSWR characteristics of an antenna on a tower may be measured from the ground without the effects of the transmission line. Measurement accuracy is 0.1 DB and 0.5 degree return loss with excellent repeatability. The system is suitable for field use allowing evaluation of the antenna and other parts of the RF system.     

A Broadband Balanced Distributed Frequency Doubler With a Sharing Collector Line

A broadband balanced distributed frequency doubler fabricated by 0.35 $mu$m SiGe BiCMOS technology is developed to operate from 4 to 18 GHz output frequency. This balanced doubler consists of an active balun and a distributed doubler. A sharing collector line is used in the balanced distributed doubler to reduce the chip size. This circuit exhibits a measured conversion loss of less than 8 dB and a fundamental rejection of better than 23 dB for the output frequency between 4 and 18 GHz. The chip size is 1.1$, times ,$0.7 mm $^{2}$.      

马鞍山有线电视宽带数据网方案

介绍了马鞍山有线宽带数据网的设计与组网方案。     

分布式非线性编辑网络

介绍了一种新的分布式编辑网络环境 ,提出利用IP网对海量节目进行存储、传输和编辑的解决方案。基于编辑工作流的分析 ,根据分布式网络的设计原则 ,充分考虑系统的可扩展性 ,该系统具有较高的实用价值     

故障网络的分布式恢复策略

网络的生存能及抗毁能力是网络规划和运营维护的关注点。本文着重介绍光纤网络在出现故障时的分布式恢复策略,其中包括故障网络恢复的控制方式,单、双向恢复方法,以及它们不同的分布式动态恢复算法。提出了今后有待解决的多层面结构的通信网络中各种恢复策略的协调机制问题。