完全图的边带宽的另一证明

图G的边的一个标号f是指边集E（G）到自然数的子集的一个一一映射。图G的边带宽为B’（G）=minB＇f（G）,B＇f（G）是G的所有邻边的标号f的差的绝对值的最大者。本文确定完全图Kn的边带宽：当n=3,4时，B＇（Kn）=2n-4；当n≥5时，B＇（Kn）=n（n-5）/2＋7。     

视频技术的发展背景

通过模拟与数字之争及市场机遇与技术支持的阐述推出视频技术的发展背景.     

A novel algorithm for Ethernet-passive-optical-network dynamic bandwidth allocation based on threshold

The Ethernet passive optical network (EPON) is the next generation of broad-band network technique. A crucial issue in EPONs is the sharing of uplink bandwidth among optical network units (ONUs). This article provides a novel dynamic bandwidth allocation algorithm, i.e. threshold dynamic bandwidth allocation (TDBA), which is based on adaptive threshold, to increase resource utilization. The algorithm uses ONU data-transmitting rate to adjust optical line terminal (OLT) receiving data threshold from an ONU. Simulation results show that this algorithm can decrease average packet delay and increase network throughput in a 10G EPON system.     

Optimal sampling frequency in recording of resistance training exercises

The purpose of this study was to analyse the raw lifting speed collected during four different resistance training exercises to assess the optimal sampling frequency. Eight physically active participants performed sets of Squat Jumps, Countermovement Jumps, Squats and Bench Presses at a maximal lifting speed. A linear encoder was used to measure the instantaneous speed at a 200 Hz sampling rate. Subsequently, the power spectrum of the signal was computed by evaluating its Discrete Fourier Transform. The sampling frequency needed to reconstruct the signals with an error of less than 0.1% was f_99.9 = 11.615 ± 2.680 Hz for the exercise exhibiting the largest bandwidth, with the absolute highest individual value being 17.467 Hz. There was no difference between sets in any of the exercises. Using the closest integer sampling frequency value (25 Hz) yielded a reconstruction of the signal up to 99.975 ± 0.025% of its total in the worst case. In conclusion, a sampling rate of 25 Hz or above is more than adequate to record raw speed data and compute power during resistance training exercises, even under the most extreme circumstances during explosive exercises. Higher sampling frequencies provide no increase in the recording precision and may instead have adverse effects on the overall data quality.     

一种应用于卫星通信的间接时间同步方法

针对卫星扩频通信系统的时间同步需求,提出一种基于GNSS授时的卫星通信前向链路间接时间同步方法。通过由星地自发自收链路与锁相环构成的钟差间接修正环路,对发送端码时钟进行闭环修正。这将使前向链路信号起始扩频码相位在到达接收端的时刻与卫星导航授时模块输出的1 PPS保持精确稳定的同步。实现了不需要位同步的扩频信号定时接收。分析并得到间接时间同步误差表达式及其与环路带宽的变化关系,给出使同步误差最小的最优环路带宽值。星地链路试验结果表明时间同步误差随环路带宽的变化关系与理论分析一致,最佳环路带宽对应的钟差间接修正环路秒脉冲1σ同步误差约为20 ns,验证了本方法的有效性。在此同步误差条件下,接收端成功地进行扩频伪码的同步和电文解调,实现了卫星导航授时对通信的辅助。     

浅谈扩频通信在无线局域网中的应用

本文阐述扩频通信的工作原理及目前无线局域网的特点和主要传输方式,并就扩频通信的四种工作方式、扩频技术的特点和扩频技术在无线局域网中的应用前景等作了介绍     

基于HFSS的双层宽带微带贴片天线的研究

采用HFSS10电磁场仿真软件设计和仿真了一种新型宽频带双层微带贴片天线,本文中天线采用聚四氟乙烯和空气两层介质,通过增加空气介质层的厚度,同时利用圆形金属电容片补偿馈电探针引起的电感,对微带天线进行耦合馈电,仿真结果表明天线的阻抗带宽达到了23%（VSWR≤2）,从而实现了宽频带微带天线的设计.     

教育城域计算机网络的建设和管理

介绍了宁波市教育城域网正常运行两年来的建设和管理经验。其中统一网络平台低投入高带宽的设计思想，主干网络通道建设技术，网络信息的建设与运行管理经验，可供借鉴。     

彩色电视倍(变)频扫描技术方案探究

本文简要介绍了彩色电视机倍(变)频扫描技术,提出了各种倍(变)频扫描技术方案的比较和分析方法。通过分析计算得出,应用倍(变)频扫描技术能有效消除行间闪烁和图像大面积闪烁,但不可能改变摄像端的分解力或信号源的内容。     

一种展宽波导裂缝天线带宽的新方法

辐射缝隙导纳及波导导内波长的频率特性，是影响裂缝天线带宽的主要因素。本文以改善这两个参数的频率特性为出发点，提出了一种展宽波导裂缝天线带宽的新方法，即用脊波导代替矩形波导作为辐射波导。仿真分析表明脊波导裂缝阵列的带宽有较大的改善，这与理论分析的结果是一致的。本文的研究成果为展宽波导裂缝天线的带宽提供了一个新的思路。