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1.
基于VLAN技术的用户访问控制和计费研究 总被引：2，自引：0，他引：2
提出了一种基于VLAN技术的宽带ISP用户访问控制和计费的解决方案,并对其基于Linux操作系统的实现、效率、优越性、计费方案方法及其与现有电信OSS接合等若干关键问题做出了深入阐述. 相似文献
2.
曹庆钰 《河北能源职业技术学院学报》2007,7(2):63-65
本文简要介绍了宽带接入网技术的构成,以及目前国际上主流并且比较成熟的宽带接入技术,并对各种宽带接入技术的优缺点进行了比较. 相似文献
3.
A novel scheme of optical modulation in 40 GHz radio-over fiber (RoF) system is proposed. It generates optical QPSK/16QAM
signals in a serial-parallel structure of Mach-Zehnder modulators (MZMs). The millimeter-wave is obtained with optical frequency
multiplication (OFM). Furthermore, modulation on optical-wave is transferred onto millimeter-wave. It can be used to increase
transmission capacity of millimeter-wave RoF systems. 相似文献
4.
Perceived benefits and barriers to the use of high-speed broadband in Ireland's second-level schools
As part of Ireland's National Digital Strategy, high-speed broadband is being rolled out to all second-level schools to support greater use of information and communication technology (ICT) in education. This programme signals a move from slow and unreliable broadband connections for many schools to a guaranteed high-speed connection with technical support. Theoretically, this should allow for behaviours and pedagogies to adapt, incorporating ICT into education. Research shows that integrating ICT into teaching and learning is a gradual process for most teachers and is influenced by a complex mix of socio-technical factors. Our data set consists of survey data from teachers and principals from a sample of second-level schools. The survey collected factual and attitudinal variables including attitudes towards ICT integration, current availability of infrastructure and barriers to ICT use, before schools received high-speed broadband connectivity. We examine the factors influencing teachers’ attitudes to ICT and their perceived barriers in adopting new technologies in their day-to-day teaching. Analysis of this baseline period is essential in an iterative digital strategy, informing future strategies, targeting policy most effectively and achieving policy objectives. While attitudes towards the potential of high-speed broadband and use of ICT are consistently positive across sub groups of schools and teachers, perceived barriers to ICT usage differ. 相似文献
5.
篮球运动现场的球员运动姿态数据的感知系统设计,可以快速捕获运动技术特征,对分析运动员的技术动作,对预测篮球运动员的训练水平和比赛表现提供数据和技术支持。传统的篮球比赛现场运动姿态数据感知系统采用VICON动作捕捉系统进行姿态数据调整,采用傅立叶变换处理方法实现数据的实时调度和处理,不能实现对宽频带大功率数据的有效感知。本文提出一种基于宽频带大功率基阵的现场运动姿态数据感知算法,并进行系统设计。分别设计了传感器设备、数据传输设备、数据处理设备和信号感知设备。对篮球运动员的人体运动姿态进行传感器感知,采用3D SUIT操作,将各个传感器连接起来,构建基于宽频带大功率基阵的运动特征提取算法,进行信息感知。系统实验结果表明,该系统具有较好的数据感知性能,能实时实现数据转换和调度,进行技术分析,篮球运动现场的运动姿态数据感知性能稳定,实时性好,实现多通道多状态的信息感知和控制,对篮球训练和比赛具有提供数据支持。 相似文献
6.
成国庆 《南通职业大学学报》2015,(2)
分析了影响射频宽带功率放大器输出功率平坦度的主要原因,提出采用动态偏置改善功率平坦度的设计方案,并重点介绍了以C8051F021为控制器,由PE4302、AT24C512等组成的动态偏置控制电路原理。基于自动测试技术,设计了动态偏置参数自动生成系统,测试结果表明,系统运行稳定,应用自动生成的动态偏置参数,功放的测量数据满足指标要求。 相似文献
7.
设计并加工了一种平面结构的宽带水平极化全向天线,该天线由四个改进的弯曲偶极子加上各自的耦合单元构成。天线在水平面内能很好地实现全向辐射特性,在4.8～6.8GHz的频带范围内,回波损耗小于-10dB,水平极化不圆度小于±0.7dB,交叉极化优于-20dB。 相似文献
8.
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. 相似文献
9.
比较常见的网络接入方式有四种:电话线+调制解调器接入,ISDN方式接入,DDN专线接入和宽带方式接入。这四种接入方式有各自的优缺点。 相似文献
10.
The Twin-Loop Antenna(TLA)has been widely used because of itsbroadband property and simply feeding,and some modified structures have been devel-oped from its prototype by Chinese engineers.But the exact design theory for TLA accord-ing to the impedance calculation has not yet been published.In this paper,the impedanceof loop in a TLA is analysed and computed by using the method of moments,and the de-sign formulae and a two-step optimization program for extending the bandwidth of inputimpedance of TLA are detailed.An example of optimized design shows that the bandwidthcan be increased up to 36.4% for VSWR≤1.10,which is wider than the bandwidth of ra-diation pattern. 相似文献