直放站集中监控管理系统

本文阐述GSM／CDMA直放站集中监控系统的网络结构，系统中心软件和直放站嵌入式软件及硬件的设计，并介绍了系统能实现的主要功能。     

现代通信直放站监控技术的分析与研究

对目前国内通信直放站的现状做了具体的分析,阐述了直放站监控技术的必要性.从结构、功能的角度对当前直放站监控系统做了具体的介绍,从硬件的角度分析了基于单片机监控系统发展过程及其工作原理,通过软件流程的研究,提出了软件设计方法.根据当前趋势简要说明了直放站监控系统的建设现状,并对今后的发展趋势做出展望.     

基于MC35的GSM直放站远程监控系统

在对GSM移动通信系统和直放站系统理论分析基础之上,重点介绍了基于MC35的直放站监控系统主控板软硬件的设计、实现。主控板作为监控系统的核心部分有着重要的作用,他要对直放站各功能模块进行监控管理,包括对直放站状态的查询、功放开关及ATT的设置并及时地将直放站的工作状态通过MC35模块主动上报给远端的监控中心。     

直放站集中监控管理系统

本文阐述GSM/CDMA直放站集中监控管理系统的网络结构,系统中心软件和直放站嵌入式软件及硬件的设计,并介绍了系统能实现的主要功能。     

直放站集中监控管理系统

本文阐述GSM/CDMA直放站集中监控管理系统的网络结构,系统中心软件和直放站嵌入式软件及硬件的设计,并介绍了系统能实现的主要功能.     

CDMA直放站的监控系统

直放站是CDMA网络设备的重要组成部分 ,文章介绍了实现CDMA直放站主机监控系统的硬件框图和主要的软件流程图     

基于ARM和GPRS的光纤直放站监控系统的设计与实现

为了改善当前直放站监控系统处理数据速度慢以及传输数据量小等缺点,基于ARM控制平台和GPRS数据传输技术,设计并实现了光纤直放站监控系统;论证了监控系统的设计方案,详细分析了其硬件系统构成和外围接口电路,阐释了其软件整体架构和工作流程,本设备实验结果运行良好,提高了光纤直放站的稳定性和可靠性,为光纤直放站系统的监控提供了一种新的方法。     

直放站通信协议之比较

直放站通信协议是移动通信运营商所有直放站与分布系统实现监控的前提条件,但目前并无国际标准组的规范可循。本文通过对目前直放站系统因通信协议带来的监控问题,对当前主流直放站通信协议进行比较,以探讨通信协议的合理性、规范性。     

基于短消息网关和在线升级的直放站智能监控系统

介绍了直放站监控系统结构体系、软硬件设计和通信协议.在阐述短消息通信格式的基础上,提出了一种基于短消息网关和在线升级的直放站智能监控系统的技术方案和实现方法.为了提高通信数据的可靠性和安全性,设计时合理地采用重发和鉴权机制,提高了整个系统的稳定性.该系统充分利用互联网与无线接入的优势,使用短消息业务,工程人员远程就能够统一规范管理直放站监控系统,从而减少了设备开发商开发、维护和升级直放站的费用.     

如何实现移动通信直放站统一网管

随着直放站在陆地移动公众网中的广泛应用,直放站监控系统的作用越来越重要。本文简述了直放站监控系统的组成及原理,提出了几种建立直放站统一网管的方式,并探讨了建立直放站网管系统标准通信协议的可能性。     

An anti‐repeater‐jamming approach based on blind source separation for the downlink of satellite communication systems

In this paper, an anti‐jamming approach is proposed for the downlink of satellite communication systems when encountering a hostile repeater‐jamming. Based on blind source separation, this approach can eliminate repeater‐jamming by separating the mixtures of the communication signals and the repeater‐jamming. Meanwhile, oversampling method is employed to transform the underdetermined mixing of signals into a determined mixing for facilitating the separation. In the simulations, the symbol error ratio (SER) of the separated communication signals can approximate the theory SER, and the anti‐repeater‐jamming capacity can arrive to nearly 28 dB.     

Repeater Fault Location for a Submarine Optical Fiber Cable Transmission System

This paper introduces a repeater fault location system for a repeated submarine optical fiber transmission system of 400 Mbits/ s at 1.3μm. The repeater fault location system is used in an out-of-service test. The fault locator transmits a test signal via a main optical fiber line, in order to make a loop-back path in one of the repeaters for returning the test signals via another main optical fiber line and to measure the bit error rate (BER) of the interrogated repeater. The test signal is a kind of pseudorandom signal that includes a low frequency component, which is assigned to the repeater as a supervisory frequency tone (SVT) signal. The BER is measured by counting the number of low frequency signal phase inversions in a time. This paper first describes the test signal generating method, SVT frequency allocation, and the filter design installed in a repeater. Next, there is a discussion of how the capability of the repeater fault locator has been experimentally verified by using two submarine repeaters, including four regenerative repeater units and three submarine optical fiber cables. As a result, a BER of less than5 times 10^{-6}is accurately measured.     

An Experimental 800 Mbit/s Four-Level Repeater Compatible with the 60 MHz Analog System

The design and performance of an experimental 800 Mbit/s repeater for four-level digital transmission over a coaxial cable is described in this paper. The 800 Mbit/s digital system exceeds the 60 MHz analog system, both in capacity and in economy. The repeater is designed to operate in repeater housings located at 1.6 km maximum spacing to be compatible with the 60 MHz analog sytsem. A nonredundant four-level line code has been employed, using a newly developed quantized feedback dc restoration technique. The most important item in realizing the high-speed multilevel repeater is the reduction of intersymbol interference. A simple quantized feedback scheme and an adjustable three-tap transversal equalizer have been used to compensate for intersymbol interference. The experimental repeater has been tested for 1.1-1.7 km repeater spacings using 2.6/9.5 mm coaxial cable. The results show that an 800 Mbit/s repeater with 1.6 km maximum repeater spacing is feasible.     

Low‐Cost High‐Performance TDD Synchronizer for WiBro RF Repeater

WiBro radio frequency (RF) repeater is used for solving the problem of partial shadow areas in the wireless communication field that uses time‐division duplexing (TDD) mode. In this paper, a method to efficiently generate TDD signals for WiBro RF repeater is proposed and its digital circuit is implemented. A TDD signal is detected from RF signals transmitted/received to/from RF repeater and then inputted again into the RF repeater, so that it can operate normally. First, the envelope of downlink signals is detected and then clamped to extract the basic form of a TDD signal using an operational amplifier circuit. Next, the TDD signal is generated by restoring and filtering the shape which has been distorted by the wireless channel. The algorithm and system to acquire TDD signal are developed with a goal to have simple but powerful functions with as little cost as possible. The proposed method is implemented as an RF‐digital integrated system and verified through the experiments under the same condition as actual WiBro service environment.     

分布式雷达主瓣间歇采样转发干扰抑制方法

主瓣间歇采样转发干扰是一种相干干扰,且该干扰从天线主瓣注入雷达,会严重影响雷达的性能。本文首先建立一发多收分布式雷达系统;并建立目标、间歇采样转发干扰数学模型;随后提出一种通过干扰辨识来估计纯干扰协方差矩阵的最小方差无失真(MVDR)抗干扰方法。通过对雷达回波脉压后的一维距离像作时频分析,并根据目标、干扰信号的时频特性差异来辨识目标与干扰,在此基础上,估计纯干扰信息,作为MVDR波束形成器的训练样本,实现对主瓣间歇采样转发干扰的抑制。最后,通过仿真验证了该方法的有效性。      

脉冲频率调制光纤传输系统原理及改进

介绍了脉冲频率调制(ＰＦＭ)光纤视、音频传输系统的原理并对关键功能电路模块作简要分析。该系统硬件集成度高,无中继传输距离长,性能价格比高,具有广阔的市场前景。     

太阳能直放站锁相环系统设计与应用

由于移动通信技术的发展,通信频率的变化范围越来越宽,为了解决太阳能直放站锁相环系统在满足输出频率和相位稳定的同时,兼顾直放站太阳能电源对整个系统实现低功耗供电的问题,文中研究了锁相环原理,分析了GSM太阳能直放站锁相环系统,采用高度集成的锁相环频率合成器和高转换效率的电源,并进行了其具体的电路设计与应用,同时进行了锁相环系统测试,满足直放站频率合成输出的性能要求。