ISO/IEC TR 13233在实验室认可中的应用

介绍了我国目前实验室认可工作的情况以及ISO/IEC TR 13233标准的内容,重点阐述了ISO/IEC TR 13233在实验室认可工作中的应用。     

DVB/OTT终端管理系统的高并发处理方案

介绍了一种基于TR069协议(CPE广域网管理协议)的DVB/OTT终端管理系统的高并发处理方案.通过设置缓存区、使用线程池、设置终端开机延迟3个方面优化系统,可以有效地解决大规模的机顶盒终端同一时刻向终端管理系统发送请求而引起的高并发问题,从而保证终端管理系统能够在高并发环境下稳定运行.     

Peak‐to‐average power ratio reduction of orthogonal frequency division multiplexing systems using modified tone reservation techniques

This paper proposed a modified tone reservation (TR) technique that can reduce the peak‐to‐average power ratio (PAPR) of the orthogonal frequency division multiplexing (OFDM) system and is able to correct errors to avoid channel interference. The TR technique is a widely used PAPR reduction technique, which divides subcarriers of the OFDM system into two sets to generate peak‐canceling signals and transmit modulated data. The subcarriers used to reduce the PAPR are called the peak reduction tone sets. The mechanism of peak‐canceling signal generation is a primary factor in determining the quality of the PAPR reduction performance of the TR technique. Currently, two signal generation mechanisms exist: TR‐gradient‐based and TR‐clipping‐based techniques. Although TR techniques can effectively reduce the high PAPR in the OFDM system, TR techniques lack the ability to correct errors. Therefore, this paper combined block coded modulation codes and TR techniques to provide the modified TR techniques with error correction abilities. From the simulation results, the modified TR techniques had a superior effect on PAPR reduction performance compared with the conventional TR technique. The modified TR technique also possessed the ability to correct errors during signal transmission. Copyright © 2015 John Wiley & Sons, Ltd.     

Novel Peak‐to‐Average Power Ratio Reduction Methods for OFDM/OQAM Systems

The tone reservation method is one of the most effective pre‐distortion methods for peak‐to‐average power ratio reduction in orthogonal frequency division multiplexing (OFDM) systems. Its direct application to OFDM systems with offset quadrature amplitude modulation (OQAM) is, however, not effective. In this paper, two novel TR‐based methods are proposed, specifically designed for OFDM/OQAM systems by taking into consideration the overlapping nature of OQAM signals. These two methods have different approaches to the generation of the peak‐cancelling signal. The first one (overlapped scaling tone reservation) generates the peak‐cancelling signal using a least squares approximation algorithm with possible adjacent symbol overlap; the second one (multi‐kernel tone reservation) generates the peak‐cancelling signal by using multiple impulse‐like time domain kernels. It is shown by simulation that, when used in OFDM/OQAM systems, the proposed methods can provide better performance than the direct application of the existing controlled clipping tone reservation method, and even outperform the multi‐block tone reservation method.     

宽带天线开关管频率特性的理论计算

本文从理论上计算了天线开关管(又称TR管)的频率特性,理论模型是谐振元件的集总参数的并联,逐级进行电纳的变换。数值计算是采取FORTRAN语言程序在向量计算机上进行的。计算曲线与实验结果比较符合。计算曲线对于宽带TR管的频带设计提供了有益的参考。     

固定式边界层风廓线雷达TR组件相关故障分析

固定式边界层风廓线雷达是一部上视、晴空探测脉冲多普勒雷达,能实时探测大气三维风场,能不间断地提供被探测高度范围内的大气水平风场、垂直气流、大气折射率结构常数等气象要素随高度的分布。对固定式边界层风廓线雷达的组成、原理进行了简单的阐述,并着重介绍了关于固定式边界层风廓线雷达TR组件相关故障的发现和排除方法。     

95122有线数字电视系统的参数及测量

介绍有线数字电视系统的关键技术参数,着重说明TS码流参数和系统传输网络参数的评价及其相关测量方法.     

TR069在家庭网络中的应用

家庭网络终漩设备的复杂性和业务的多样性对终漩管理提出了更高的要求，为此数字用户线（DSL）论坛专门制订了用于终端的网管协议——TR069。TR069协议在架构设计上使用超文本传输协议（HTTP）的客户机／服务器（C／S）模型，并充分借鉴了很多Web的成熟技术，使得协议的实现相对简单，并且具有很好的扩展性。在管理参数定义上，TR069协议完全针对终端业务特性而制订。通过部署基于TR069的网管系统，可以在很大程度上减少用户的配置／管理工作，提高设备的易用性和可管理性，便于家庭网络中设备的快速部署和业务的迅速开展。     

光进铜退下家庭网络管理体系架构研究

随着光进铜退的推进,家庭网络管理体系如何演进,为用户提供更优体验,是电信运营商急需解决的问题。本文探讨在光进铜退下,实现家庭网络管理体系对家庭终端及家庭网络的可管可控,进而实现家庭业务零配置开通和家庭终端的远程故障处理。