通信波道 的英文怎麼說
中文拼音 [tōngxìnbōdào]
通信波道
英文
communication channel-
Digital speech technology has been widely used in many fields of communications in recent years, but it is just at beginning to use acoustical wave to implement underwater digital speech communications, which mainly results from the bandwidth - limited underwater acoustic communications channel and its high temporal and spatial variability
目前，數字語音技術已廣泛應用於許多通信領域，但是在水下利用聲波進行數字語音通信卻是剛剛起步的新技術，這主要是由於水聲通道有限的通信帶寬及其時變、空變等特性所決定的。The ionosphere is a complex medium, which is aeolotropy, asymmetry, dispersive and changes randomly with time. in order to improve the communication quality of the shortwave that depends on the ionosphere, we should have aknowledge of the current condition of the ionosphere in real time. the backscatter sounding of high frequency can diagnose the real - time channel characters for shortwave communication or hf radar, which is great assistant to shortwave communication and hf radar
電離層是隨機時變，各向異性，非均勻、色散的復雜介質。為了保證依賴于電離層進行的短波通信質量，必須了解電離層的實時狀態信息。高頻返回散射探測可以實時監測與短波通信或高頻天波雷達相關的天波傳播通道的狀態，對短波通信和天波雷達工作起了重要的輔助作用。Capacity series and radio - frequency channel arrangement for analog microwave relay systems
模擬微波接立通信系統容量系列及波道配置Finally, with the optimized chaos sequences, the results of software simulation on vhf - rc indicates that ds - ss outbalances the bpsk system without spread spectrum due to ber and the ds - ss with kent sequence is better than the one with golden sequence in some extend
最後本文對數字混沌序列進行了優選，在超短波中繼通道模型上的模擬結果表明混沌直擴通信相比于非擴頻的bpsk通信在誤碼率方面明顯較低；相對于線性擴頻碼（ gold序列） ，同樣誤碼率較低。Shortwave channel is time varying transmission channel. it has dispersion in frequency and time domains. this characteristics hinds the data transmi - ssion at high speed and the correction of received data. in this dissertation i have analyzed the statistic characteristic of shortwa - ve channel, established the model of shortwave channel and simulated the rayl eigh fading distribution. the technology of spreading spetrum has been proved that it has the capability for anti - multipath and discerning multipath
在短波通信中，由於通道的時間色散和頻率色散，引起多徑展寬和多徑衰落，前者限制了數據的傳輸速率，後者造成短波數據通信中出現突發錯誤，為了解決多徑效應對短波通信的影響，本文所做工作如下：首先詳細分析了短波通道的統計特性，建立其數學模型；其次分析了擴頻通信的特點，從理論上證明擴頻技術不僅具有抗多徑干擾能力，而且具有分離多徑的能力；介紹了傳統的rake分集合併技術的特點。In this thesis, for the merits of high frequency spectrum utility factor and high - speed data communication, the ofdm is introduced into the underwater acoustic communication. combined with fec to combat the frequency - selective fades and isi in the underwater acoustic channel, high speed data transmission is realized by employing ofdm technology
本研究嘗試將ofdm技術引入水聲通信領域，利用該技術頻譜利用率高，多載波并行傳送的特點，結合通道編碼，以克服水聲通道多徑干擾引起的頻率選擇性衰落和碼間干擾，獲得高速率數據傳輸。Actively mode - locked erbium - doped fiber lasers ( edfls ) with a high repetition rate and multi - wavelength fiber lasers are attractive optical sources in future ultra - high speed and all - optical communication systems
多波長摻鉺光纖激光器（ mw - edfls ）可以同時為多個波長通道提供所需光源，被認為是未來長距離大容量的光纖通信系統的理想光源。Firstly, the airborne electromechanical system, the development of bus protocol, power line channel and power system are described in the dissertation ; secondly, the algorithm of qpsk and root raised cosin are discussed ; thirdly, the designation of the hardware and software of the modem board, based on qpsk, built up with dsp and cpld are given. the high - speed data transporting card of airborne electromechanical communication system, which is based on plc, are put forward in our country
本文介紹了飛機電力線載波數據通信系統的結構，並對低壓電力線的通道特性進行了分析；對qpsk調制演算法及均方根升餘弦低通濾波演算法進行了詳細論證；設計出基於qpsk的調制解調模塊，並在此基礎上，研製出以dsp和cpld為最小系統的調制解調硬體電路板，開發了調制解調模塊電路板的應用軟體程序。In wireless communication, the relative movement between the transmitter and the receiver may cause the change of the electromagnetic wave propagation path, thus makes the channel become a random time - variety channel
在無線通信中，發射機和接收機之間的相對移動會造成電波傳播路徑的改變，從而使通道變成隨機時變通道。In modern shortwave communication, the length of signal existence time in single channel is very short for reducing the probability of being intercepted, thus the difficulty of signal detection and extraction increased
摘要在現代短波通信中，作為低截獲率通信手段之一，單個通道內信號持續時間大大縮短，從而增加了信號檢測與提取的難度。This thesis presents the studies of the physical layer of power line communications, which is an ofdm - based transmission system. it gives feasible algorithms, and primary implementation of some key modules is discussed as well
本文主要的研究對象使基於ofdm的電力線載波通信傳輸系統的物理層，對電力線載波通道進行了著重的分析，給出響應的估計演算法以及硬體實現模塊。Considering the requirement of communication network, a local area computer communication system of plc based on usb interface was given after analyzing the application model of plc. then after theoretical analysis and digital simulation, the plc modem and the computer interface models were designed. the design of software about the two models was also finished
本文首先介紹了電力線通信技術在國內外的研究概況，分析了電力線載波通道的傳輸特性，討論了適合於電力線通信的擴頻載波通信方式，然後結合通信網路的要求，在分析電力線通信應用模式的基礎上，提出了一種基於usb介面的室內計算機電力線通信方案，進行了理論上的分析和數字模擬，設計了電力線modem模塊和計算機介面模塊，編制了相應的軟體程序，並對軟體進行了測試分析。This paper presented a general systematic view, application and current development of the power line carrier transmission technology, and clearly compared some existing power line carrier communication chip with each other. then the authors analyze the channel " s characters of low voltage power line, and formed an abstract carrier channel model. using this as its basis, a new kind of transmission technology is designed that adopted transmission technology combining the spread spectrum modulation with channel coding, which can solve the problems above mentioned to a certain degree, and need not pay for high cost
文章不僅全面地介紹了電力線載波通訊技術的特點、應用及其發展狀況，還對目前的電力線載波通訊晶元進行了比較；並通過對低壓電網通道特性的分析和研究，抽象出其載波通道模型，在此基礎上，提出了將擴頻調制和通道編碼相結合的傳輸技術用於低壓電力線載波通信，這可以在很大程度上解決電力線的干擾問題，且不必付出高昂的代價。In a tdma network, multiple users share the common medium ( or channel ) and bandwidth but different intervals of time. in case of the burst mode, the carrier of the modulated signal needs to be synchronized in a very short time. the common approaches such as a costas - loop and so on are no longer suitable any more
在一個時分多址（ tdma ）通信網路中，多個用戶通過不同的時間段共享一個傳輸線路（或者通道）的帶寬資源，每個用戶只能在分配給自己的時間段內進行通信，這種突發方式信號的解調要求載波恢復要在很短的時間內完成，我們以往在連續信號解調器中採用的costas環等方法很難適應這種要求。However, the paralleling communication can meet the requirements of high speed and fidelity in underwater signal transmissions. ofdm is a kind of novel paralleling transmission technology. the principle of ofdm is that the whole bandwidth can be divided into some subchannels, the high - speed serial signal stream is modulated by some orthogonal subcarriers
正交頻分復用（ ofdm ）是近年來數字通信中流行的一種并行傳輸新技術，其核心思想是將整個可用頻帶分割成多個正交子通道，將待傳輸的高速串列碼流并行的調制在這些子通道載波上。In this thesis, first, we present the theory of sess system, the generation of the sess spreading code and its characteristics and the acquisition theory of conventional spread spectrum communication system. an efficient acquisition scheme based on periodically transmitting the synchronization head, which is composed of binary chaotic codes, using the matched filter and automatic decision threshold - level control based on a so - called constant false alarm criterion for sess system is present. the acquisition model of sess system is built and simulated in the awgn channel, the raleigh fading channel and imulti - address interfere condition
本文首先概述了自編碼擴頻通信的原理、自編碼擴頻序列的產生方法及其特性和擴頻通信系統編碼同步的理論，然後針對自編碼擴頻通信系統提出了擴頻序列捕獲方案:周期性地加入混沌序列同步碼，並採用恆虛警率匹配濾波器捕獲法;在加性白高斯噪聲通道、瑞利衰落通道和多址干擾情況下進行了模擬，分析了各種捕獲性能:在選擇性能最優的混沌序列、適當的序列長度、虛警概率及門限值的情況下，可以獲得較短的捕獲時間和較大的捕獲概率。Domestic satellite communication earth stations - general technical requirements part 5 : intermediate data rate digital carriers
國內衛星通信地球站總技術要求第五部分:中速數據數字載波通道By theory and practice simulation, the several types of constant envelope modulation techniques are analyzed and compared, including theirs modulation principle, phase path, the modulated wave envelope, power spectrums, error bit rate and the influence of its power spectrums of the band - limited and non - linear, etc. especially we have researched the ijf - oqpsk modulation technique, and the performance of its inter - symbol interference and time jitter free, and its strongly resisting of spectral spreading
結合理論和實驗模擬結果，分析討論了衛星通信中的各種恆包絡調制技術，對它們的調制原理，相位路徑，已調波包絡，功率譜密度，誤碼性能，以及帶限非線性通道對其功率譜的影響等方面都作了研究和比較。特別研究了ijf ? oqpsk在消除碼間干擾和定時抖動方面的性能及其優良的旁瓣特性和抑制頻譜擴展特性。The advantages of using leo satellite are as following : on the one hand the satellite orbit is low, so the transmission delay is short, the power loss is small ; on the other hand the development of cell communication, multi - access, frequency multiplex and etc also provide a technique guarantee to the leo satellite - mobile - telecommunication. so the leo system is considered to be a satellite - mobile - communication system with a great future
低軌道衛星是一種運行於1000公里左右的高空中的人造衛星，利用leo衛星實現個人通信的優點在於：一方面衛星的軌道高度低，使得傳輸延時短、路徑損耗小，多個衛星組成的星座可實現真正的全球覆蓋，頻率復用更有效：另一方面蜂窩通信、多址、點波束、頻率復用等技術的發展也為低軌道衛星移動通信提供了技術保障。Wdm has promoted greatly the development of optical communications, optical net based on wdm technology will become the main transmitting flat roof in telecom net. in wdm, with increasing the channel density, a new kind of optical component, interleaver, emerges as the times require. in this paper, several main interleaving technologies are analyzed quite deeply, and mgti interleaver is investigated experimentally, one prototype device with better experiment results is achieved
波分復用技術（ wdm ）對于光通信技術的發展起到了巨大的推動作用，以dwdm技術為核心的光傳送網將成為電信網的主要傳送平臺。在密集波分復用技術中，隨著通道復用密度的提高，一種新型光器件? ?光學梳狀濾波器（ interleaver ）應運而生。分享友人