论监管措施在中波同步广播（电视精密偏置）中的特殊作用

同步广播（电视精密偏置）由二个或若干台组成开路网的形式工作，且是实时的，良好同步要求达到的精度又比较高，离开了监控网就不能正常运行，因此有效监管措施实施中保证网正常运行的重要手段之一。本文展示了实际运行网中的一些问题，论述了监控措施在同步广播中的特殊作用、难点、网管经验及同步网中一些问题的解决方法，提出实施良好同步的一些建议。     

同步激励器鉴相电路的改造

同步激励器鉴相电路的改造宋占国（吉林省广播电视厅６６１台）同步激励器是保证中波广播同步网高质量运行的关键设备。目前，大多数中小型发射台使用的同步激励器为早期产品ＴＢＪＬ－１型。因其故障率高、维护不方便，我台对其进行了改造，采用集成电路，故障率相应降低...     

调频同步广播发射台站远程监控系统设计——基于GPRS的APN网络技术

调频发射台站伴随着广播的快速发展而迅速增加,许多台站都处在无人值守的状态下运行。为了实现对这些台站及时有效地管理,建立科学可靠的远程监控系统非常重要。结合贵州综合广播、交通广播同步覆盖台站的实际情况,采用了GPRS的APN网络技术,根据安全播出和管理工作的需要,对综合广播同步网、交通广播同步网分别建立了远程监控管理系统。实现了对同步发射台站工作数据地实时采集,对台站工作状态地实时控制和故障报警状态地及时处理,大大提高了同步覆盖工作的效率和智能化管理水平。     

数字网同步技术与设备维护

本文主要就数字内步网结构、同步网内的时钟、通信楼内名种通信设备四步运行的实施以及同步设备维护管理等方面的技术进行了较为详细的介绍，并结合本人在安装调测中及日常所遇到的问题，探讨了故障现象、原因分析及其解决的方法。     

调频同步广播的最新技术用其应用

本文介绍了调频同步网广播的最新技术进展,同时对新的动态自动同步系统与传统的同步方式进行了比较,最后介绍了调频同步网的全套解决方案及成功案例。     

利用调频精密同步广播技术进行单频组网

应用调频精密同步广播技术,实施模拟调频同步广播网同频保护率趋于OdB,突破了小功率多布点的模式,实现了大功率覆盖。本文就同步网的建设、收测、收听效果进行介绍。     

数字网同步技术与我省数字同步网现状

首先介绍了数字同步的几个概念,然后结合全国数字同步网的建设和管理,叙述了我省同步网的现状,并针对同步网管的发展趋势提出了自己的看法。     

SDH通信网的同步技术及应用

SDH（同步数字系列）是一种通信新技术，具有很多优点，各国新建的通信网络或点对点通信均采用SDH技术。在通信网从PDH向SDH过渡过程中，为使通信网的信息能灵活可靠地交换和传输，必须实现网同步，也就是要形成相对独立的数字同步网。SDH同步网能准确地将同步信息（基准时钟）向同步同的各同步节点传递，从而建立、调节并保持同中的同步时钟。SDH网元应综合进同步网中，构成同步网的一部分。一、同步网结构我国同步同的时钟等级分为4级，与交换网的等级对应。为了保证有更好的同步性能，也允许越级连接，即低等级时钟可直接从同一…     

专用通信网的网络同步方式研究

在数字同步网络的概念、方法、必要性和数字同步系列的基础上，探讨了有关专用通信网的同步方式选择和规划问题，给出了建设数字同步网的一些研究结果。     

浅谈GSM移动通信网的同步

同步网是通信网的重要辅助网。本文对GSM移动通信网络从基准时钟源到每一个基站的从上而下的同步网作出综述，说明了同步网各层次的原理及其在移动电话网中的应用，分析各环节的建网方案，指出需要避免的同步障碍。     

南京电视台高标清同播平台技术应用策略

在综合现阶段高标清同播系统搭建平台模式及特点的同时,结合南京电视台既有播出系统技术平台基础,开展高标清同播系统技术平台设计与搭建的具体思考与实践,较为详细地介绍了高标清同播系统建设的基本思路,以及同播技术中所涉及的2个频道播出一致性策略,高标清频道幅型变换流程控制策略,素材质量技审策略和视频素材编码等应用策略,并对建成的共享模式下源分离的高清同播系统结构进行描述和应用总结。     

The simulcasting technique: An approach to total-area radio coverage

The simulcasting technique described provides total-area radio coverage on an automatic basis where the use of multiple transmitter and receiver sites is required to achieve acceptable communications coverage over rugged terrain or wide areas. In this technique the same audio information is simultaneously broadcast over several transmitters operating on a single nominal-carrier frequency. Special attention must be given to transmitter-frequency stability and audio envelope characteristics. A master tone-distribution system is essential when incorporating a continuous tone-controlled squelch system (CTCSS). Use of the simulcasting technique reduces effects of fading in a mobile environment through transmitter space diversity. An application of the simulcasting technique to a coordinated FM-UHF law-enforcement communications system in Orange County, CA, is described.     

Performance Analysis of a Sectorized Distributed Antenna System with Reduced Co-Channel Interference

1IntroductionThe next generation mobile communication systemissupposedto provide high data rate services such as Inter-net access and multi media applications whichare morelikelyto be affected by Inter-Symbol-Interference(ISI)inwireless multi-path fading …     

Simulcast packet transmission in ad hoc networks

In previous work, unequal error-protection techniques have been applied to improve the throughput of a wireless communication system in which a transmission is received by several radios with different capabilities. For instance, these capabilities may correspond to differences in path loss, fading, or interference. By taking advantage of the broadcast nature of the channel, additional messages for the more-capable receivers can be included on transmissions to the less-capable receivers at very little cost (in terms of required energy at the transmitter or error probabilities at the receivers). This technique has been termed simulcasting or multicast signaling. In this paper, we consider the use of these techniques in an ad hoc network. These techniques impact the link throughput, end-to-end throughput, and network connectivity. We investigate how the choice of parameters for the simulcasting technique affects these network performance metrics. The results indicate that a properly chosen simulcasting technique can improve the link and end-to-end throughput in wireless ad hoc networks with only a slight degradation in other metrics, such as network connectivity.     

Effective paging procedure for the optical feeder microcellular system

The paper considers a paging problem in the optical feeder microcellular system where group simulcasting and dynamic channel allocation technologies are incorporated. The objective is to propose an effective paging procedure whose performance is measured in terms of paging load, average paging delay, and paging success probability. In the paging procedure, paging signals are transmitted via group simulcasting, for which the control channel is allocated dynamically. The performance of the procedure is analyzed in an approximate queueing network model. The proposed procedure is then compared in performance with a simulation approach, from which the procedure is found to outperform any previous methods in the literature.     

一种基于参差QAM的全数字HDTV传输调制技术的研究

数字HDTV地面传输技术中的一个基本要求是能与现有模拟电视同播。本文提出一类新的数字HDTV调制方式。计算机模拟和分析表明，此方式较适于与现有电视同播，且其抗干扰性能优于QAM和VSB方式。硬件实现也较简单。     

Delay detection method using cross-spectrum for multitransmitter simulcasting

The authors propose a precise delay detection method using cross-spectrum which can be adopted for phase synchronisation of high speed multitransmitter simulcasting mobile radio communication systems. It is also shown that the detection error of this method is improved by pseudorandom noise (PN) signals and the minimum square error estimation.<>     

Forward Link Performance Analysis in CDMA Distributed Antenna Systems with Imperfect Channel Estimation

1　Introduction　The Distributed Antenna (DA) system has been proposedas a promising antenna architecture for the future wirelesscommunication systems[1~10].　In the DA systems, with remote antennas, the presentcellular structure is removed and cells are not divided geo graphically, but according to the user needs. That is, ac cording to the channel estimates computed via pilot signals,the Processing Node (PN) continuously measures the chan nels between the mobiles and the remote ante…     

Capacity analysis in CDMA distributed antenna systems

In this letter, the effect of maximal ratio combining (MRC)-based macrodiversity on the reverse-link and forward-link capacity in code division multiple access (CDMA)-distributed antenna systems is analyzed. The concept of virtual cell is illustrated, and the analytical outage probability expressions are derived. The present investigation shows that on the reverse link, the interference can be suppressed greatly with macrodiversity, which leads to a significant increase in capacity. However, on the forward-link, it is proven that if simulcasting is used in CDMA-distributed antenna systems, the forward-link capacity cannot increase with macrodiversity whatever power allocation scheme is adopted. Based on the analysis of the cause of capacity loss, a new transmission scheme is further presented and the optimal power allocation scheme is derived. It is shown that, in this case, the forward-link capacity increases rapidly with the number of involved distributed antennas.