However , in the course of the intercommunion , speech signal is disturbed and polluted inevitably by surroundings and transmission mediums . as a result , we are unable to catch on the meanings of speech signal 但是人们在语音通讯过程中不可避免的会受到来自周围环境、传输介质的干扰，引入了噪音，影响了我们的听辨。
In order to overcome in collision of transport media access , a network middleware based on rtcc protocol should be built up , through which real - time communication can be achieved 针对共享式以太网的介质访问方法以及该方法的弊病，设计了一层基于rtcc协议的网络通信中间件消除传输介质访问冲突，达到实时化改造的目的。
These standards differ in bit rate , frame rate and spatial resolution . as digital video application becomes more popular , there are increasing needs to dynamically convert the video between different formats 这些标准在语法格式、压缩效率、码率、分辨率等方面不尽相同,对应的传输介质以及要求终端处理能力也不同。
The objective of this paper is to utilize low - voltage power line as the transmission medium of pas and develop a pas based on transmission over low - voltage power distribution networks , in order to resolve the defects existing in conventional pas 本文要解决的问题是如何利用低压电力线作为pas的传输介质，研制基于低压配电网传输的pas ，克服传统pas在应用中存在的缺点。
As digital video application becomes more popular , there are increasing needs to dynamically convert the video between different formats . the transcoding of compressed video stream is to transcode a compressed video stream from one format or standard to another 这些标准在语法格式、压缩效率、码率、分辨率等方面不尽相同，对应的传输介质以及要求终端的处理能力也不同。
For some applications , a fast , industryspecific and user - friendly switch must simply have more to offer ? as in the case of medium and large fast - ethernet solutions or highly accessible networks with fast media redundancy function 对于某些应用，满足快速、工业特征以及交换机操作简单等方面的要求是不够的? ?例如在一些中型和大型的以太网络解决方案中，或是要求极高可访问性的网络，快速的传输介质冗余功能是必需的。
This thesis , based on the design methods of optical devices and requirements of communication system , mainly analyses the inter - device coupling process , and has designed some optical devices in theory , some of which are substantiated in experiment 本文结合光器件的设计方法和系统对光器件的要求，分析了光通信器件中器件与器件之间的光束耦合过程，以及光束在不同传输介质中的传输特点，从理论与实验两方面作了一些工作，主要概括为以下几方面：一
This paper introduces present application status of some media for image ( video ) transmission and puts forward the idea of the image ( video ) transmission system based on transmitting over low - voltage power distribution networks , which does n ' t require special transmitting networks 本文对目前的图像(视频)传输系统使用不同传输介质的情况进行了分析以后，提出了基于电力载波的图像(视频)传输系统的设计方案，该系统能够免除铺设传统的图像(视频)传输网络。
New standards are presented continuously , link media type is developing and the line speed is updating continuously . in 1998 , the ieee802 . 3z gigabit ethernet standard was ratified , it use fiber as it ' s link media , line speed was upgraded up to 1 , 250 mbps . it offers the users wide digital highway 到1998年， ieee正式提出了编号为802 . 3z的千兆位以太网标准1000base - x ，采用光纤作为传输介质，使用高达1250mbps的基带传输速率，为用户提供了宽阔的数字高速公路。
Many international video compression standards have been established for various applications and periods . these standards have many differences on syntax , resolution , bitrate and compression efficiency . the corresponding transmission media and the ability of terminal processing are different too 基于不同的应用时期和不同应用环境,一些国际组织建立了一系列的国际视频压缩编码标准,这些标准在语法格式、压缩效率、码率、分辨率等方面也不尽相同,对应的传输介质以及要求终端的处理能力也不相同。
