通信系统

Furthermore, M2M communication system is totally different from modern cellule systems, the exist channel model could not be used to describe the propagation properties of the M2M fading channels, meanwhile, there are not sufficient research results could be used to explain the space-time-frequency characteristics of M2M channels.

利用这些信息，通信系统才能设计得具有理想或接近理想的性能。M2M通信信道不同于经典的蜂窝网络信道，目前已有的许多信道模型不能运用于M2M通信系统，也没有已知的信道模型可以直接用来描述M2M信道的衰落和空-时-频域行为。

Cyclic Redundancy check code is recommended by International Telecommunications Organization , used in the digital communication system error control coding way (given several coding generator polynomial), they have been widely used by the people in the digital communication system.

循环冗余检错编码是国际通信组织推荐的用于数字通信系统的差错控制编码方式（给出了几种编码的生成多项式），已被人们在数字通信系统中广泛地使用。

Looks from the system communication effect, this system has a higher antijamming, the anti-signal weakens ability, the system can achieve a farther transmitting range, simultaneously because the communications system essential part SC1128 (Spread Spectrum / solution expand chip) is specially designed according to the domestic low power line characteristic, the performance price is high, these are all advantageous to the system's promotion.

从系统的通信效果来看，本系统有较高的抗干扰，抗信号衰减的能力，系统可达到较远的传输距离，同时由于通信系统的关键部件SC1128是根据国内低压电力线特性而专门设计的，性价比高，这些都有利于系统在做进一步的完善后在国内自动抄表行业内的推广。

The method has the ability to resist the gusty noise in the channel and improve the quality of the chaotic communication.

该方法能有效抵御突发噪声干扰对通信系统的影响，提高混沌调制通信系统的通信质量。

The simulation software is powerful which makes the process of design and analysis of communications system simulation more intuitional and convenient.

通信系统仿真贯穿着通信系统工程设计的全过程，对通信系统的发展起着举足轻重的作用。

Communications units used by the communications terminal are measured. An economic efficiency associated with the use of the terminal to communicate with the first and second mobile radiotelephone communications systems is determined from the measured communications units and the first and second stored critical values.

测量出通信终端所用的通信单位数后，根据测得的通信单位数和存储的第一和第二临界值就可以确定与使用终端与第一和第二移动无线电话通信系统的通信关联的经济效率。

The current second-generation and third-generation (3G) mobile communication systems operate with narrow audio bandwidth limited to 200-3400Hz.As wireless systems are evolving from voice-telephony dominated services to multimedia and high-speed data services, the introduction of a wider bandwidth of 50–7000 Hz speech codec which provides substantially improved speech quality and naturalness is quite necessary. The Adaptive Multi-rate Wideband speech codec which was selected by 3GPP/ETSI and ITU-T can provide natural, present and comfortable codec speech and have higher intelligence and robustness in wireless systems. A wide range of applications are envisioned for AMR-WB, including ISDN wideband telephony and audio/video teleconferencing,Voice over IP and Internet applications such as IP video conferencing, voice mail, voice chat, broadcast, and voice streaming.

随着现代无线通信特别是多媒体通信的发展，人们对语音通信的质量要求越来越高。3GPP/ETSI TS026和ITU-T 722.2标准确定的自适应宽带语音编解码器AMR-WB具有的低比特率、互操作性和高语音质量，使之不仅能够应用于无线通信领域，而且可广泛应用于其他各种通信系统和平台，包括：VoIP、因特网、PSTN高质量音频会议、音频流、ISDN宽带电话、ISDN可视电话和电视会议等。

In the article, it briefly analyzes the necessity of monitoring the hydric parameters and the development status of monitoring system about the electronic power, then a real-time monitoring system for generator hydric parameters is presented, which applies the configuration software MCGS, radio-communication SMS, Modbus protocol and RS-485 bus .in the design of the system, MCGS is used to configurate the interface of superordinate computer and the device component of the wireless communication is authorized by Visual Basic; the transmitting and receiving flow through GSM(Global System for Mobile communication)in the way of SMS. The design of the smart communication module, which based on the RS-485 bus and Modbus protocol and the wireless communication interface module, which is connected with the wireless terminal based on Siemens TC35, are also expounded.

该方案利用MCGS组态软件进行上位机监控界面的组态；利用Visual Basic语言进行上位机无线通信设备构件的编制；并利用SMS通过全球移动通信系统GSM(Global System for Mobile Communication)网络实现报警等数据的无线传输；以Flash型超低功耗16位单片机MSP430F149作为通用通信模块控制器核心，开发出了基于RS-485总线模式和Modbus通信协议的远程数据采集模块，以及基于Siemens TC35的无线终端相连的无线通信接口模块。

Because It has stronger ability of resisting narrow band,multipath and jamming interference than that of the conservational communication systems,and also has advantages of concealed information and multiple access secure communication,thus the spread spectrum communication technology draws the people's attention more and more.

由于扩频通信系统与常规的通信系统相比，具有很强的抗窄带干扰，抗多径干扰，抗人为干扰的能力，并具有信息隐蔽、多址保密通信等优点，因而越来越受人们的重视。

Communication;Communication systems;Communication technology;Construction;Data;Data exchange;Data processing;Data processing system;Definition;Definitions;Earth's surface;Encoding;Geodesy;Geographic information;Geographical;Geography;Geology;Geomatics;Geotechnics;Information;Information technology;Modelling;Reference materials;Reference model;Standardizations;Unified Modeling Language

中文标题地理信息。参考模型中文主题词通信；通信系统；通信技术；建筑；数据；数据交换；数据处理；数据处理系统；定义；地球表面；编码；大地测量学；地理信息；地理的；地理；地质学；地理信息学；土工学；信息；信息技术；建立模型；参考材料；参考模型；标准化；统一建模语言

The absorption and distribution of chromium were studied in ryeusing nutrient culture technique and pot experiment.

采用不同浓度K2CrO4(0，0.4，0.8和1.2 mmol/L)的Hoagland营养液处理黑麦幼苗，测定铬在黑麦体内的亚细胞分布、铬化学形态及不同部位的积累。

By analyzing theory foundation of mathematical morphology in the digital image processing, researching morphology arithmetic of the binary Image, discussing two basic forms for the least structure element: dilation and erosion.

通过分析数学形态学在图像中的理论基础，研究二值图像的形态分析算法，探讨最小结构元素的两种基本形态：膨胀和腐蚀；分析了数学形态学复杂算法的基本原理，把数学形态学的部分并行处理理念引入到家实际应用中。