一种数话兼容VSAT网络模型及其性能分析

本文提出了并讨论了一种新的数／话兼容ＶＳＡＴ网络实现方案：在不改变ＤＡＭＡ／ＳＣＰＣ这类ＶＳＡＴ系统的主要拓扑结构和通信单元的硬件的情况下只通过更改软件设计而使网络的数／话兼容能力得到较大提高。     

VSAT卫星通信网与ISDN互连的几个问题

本文主要介绍卫星广域网(SWAN)的组成与应用,TCP/IP协议,VSAT网与ISDN互连的几个问题。     

A Ka‐Band 6‐W High Power MMIC Amplifier with High Linearity for VSAT Applications

A Ka‐band 6‐W high power microwave monolithic integrated circuit amplifier for use in a very small aperture terminal system requiring high linearity is designed and fabricated using commercial 0.15‐μm GaAs pHEMT technology. This three‐stage amplifier, with a chip size of 22.1 mm² can achieve a saturated output power of 6 W with a 21% power‐added efficiency and 15‐dB small signal gain over a frequency range of 28.5 GHz to 30.5 GHz. To obtain high linearity, the amplifier employs a class‐A bias and demonstrates an output third‐order intercept point of greater than 43.5 dBm over the above‐mentioned frequency range.     

基于跳速MF-TDMA VSAT系统的实时BOD技术及应用

卫星系统资源高利用率和业务QoS（服务质量）保证是卫星系统设计的两个重要目标。但两者相互矛盾。导致该矛盾的根本原因是文件传输业务等的高突发性和流业务等的高实时性,通过更有效的带宽动态按需分配BOD（Bandwidth on Demand）机制可以解决上述矛盾。近来,针对用户业务量大,对实时性要求极高的情况,出现了一种基于MF-TDMA VSAT系统的跳速MF—TDMA VSAT系统。该系统所具有的实时BOD功能,能够有效保障实时性业务的带宽和服务质量,即便有较重业务突发时,对实时性要求极高的流业务也不会产生抖动、断续等问题,保证了传输数据的QoS要求。     

发展中的VSAT技术

介绍ＶＳＡＴ最新技术及发展趋势。帮助用户合理规划和选用ＶＳＡＴ系统。     

Comparison of the simulated performance of a vsat satellite link with measurements

This paper combines a number of features. First the simulation of the transmission performance of a K_a-band VSAT system (CODE) is presented. The results are used to verify the systems design that was performed for CODE and to demonstrate that the implementation margin due to intermodulation noise, adjacent channel interference, filter ISI, amplifier non-linearities and phase noise was sufficient. In the design of VSAT systems of this type phase noise was thought to be particularly important, and a new and detailed simulation of its effects is presented in the paper. For the first time, experimental measurements of system degradations have been taken on a VSAT system which have been used to verify simulation results. This was particularly important for the new phase noise simulation results and good agreement was obtained. An overall loop-back experiment using the Ka-band VSAT terminal with the Olympus satellite shows good agreement with the simulation results. Finally, the availability of experimental results has enabled us to compare the accuracy of TOPSIM III and BOSS simulations for the VSAT system. The paper indicates some shortcomings in the TOPSIM III simulation of phase noise and highlights the generally good agreement obtained with experimental results by the BOSS simulations.     

分组卫星话音／数据综合的混合多址协议性能研究

本文讨论了一种用于分组话音／数据综合的混合多址协议，该协议是固定分配与随机访问的混合，并且赋予话音分组优先传输权，从而保证了无重传话音分组有较小的丢失概率。本文进行了详细的理论分析，并得出了性能比较特性，所得结果认为这是一个兼顾话音／数据综合的较好协议，且具有一定的灵活性。     

VSAT及其迅速拓展的全球市场

本文简述了ＶＳＡＴ的概况及其终端的分类，指出交互型ＶＳＡＴ是今后发展的重点，着重介绍了国内外ＶＳＡＴ的市场和已建的ＶＳＡＴ网络。     

甚小口径终端卫星小站远程监控系统设计

为了减少VSAT(甚小口径终端)卫星小站设备"软故障"排除需要的资源投入,设计了一种基于专用电话网的VSAT卫星小站远程监控系统;利用VSAT小站设备自身的状态监视和故障诊断功能,通过标准的RS-232串口和电话网进行通信,辅以相应的硬件和软件支持,实现对VSAT小站设备的远程监控、故障诊断以及参数配置;经测试,在波特率为9600、2400、1200、300时,系统均能成功实现对小站设备进行远程状态监控、故障诊断和参数配置,极大提高VSAT卫星小站的技术保障力量,具有一定实用性和推广应用价值.     

铁路站场通信系统的研究与设计

对某铁路站场通信系统进行了系统性设计,该系统包括IP软交换系统、VSAT卫星通信系统、视频监控、周界报警系统、安防监控系统、通信电源系统和综合布线系统5个部分,并对6个系统的功能和技术指标进行了分析,为工程设计提供参考.