載波間通道 的英文怎麼說
中文拼音 [zǎibōjiāntōngdào]
載波間通道
英文
intercarrier channel- 載 : 載Ⅰ名詞(年) year : 一年半載 six to twelve months; six months to a year; 三年五載 three to five ...
- 波 : Ⅰ名詞1 (波浪) wave 2 [物理學] (振動傳播的過程) wave 3 (意外變化) an unexpected turn of even...
- 間 : 間Ⅰ名詞1 (中間) between; among 2 (一定的空間或時間里) with a definite time or space 3 (一間...
- 通 : 通量詞(用於動作)
- 道 : Ⅰ名詞(道路) road; way; route; path 2 (水流通過的途徑) channel; course 3 (方向; 方法; 道理) ...
- 載波 : signal carrier; carrier wave; carrier: 3路載波 three channel carrier載波傳輸 carrier transmission...
- 通道 : thoroughfare; passageway; pass; enterclose; gallery; drong; tunnel; avenue; alure; way; row; key ...
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This arithmetic divides the wavelet coefficients of carrier image into 27 - classes by the background luminance, the texture and the edge mask character of visual system ; then after encrypting watermark image with magic cube transformation, the ycbcr model is employed, it embeds the watermark sequences in the carrier image with different intensity according to the coefficients " classes of carrier image in y channel
首先,將載體rgb圖像轉換到ycbcr顏色空間,然後提取亮度通道y ,將其進行小波變換,然後利用人眼視覺模型對載體圖象分解后的小波系數進行分類。其次,對有意義的水印圖像分別進行3次不同的魔方置亂,得到3個隨機水印序列。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。For example, carrier frequency offsets, which are caused by the inherent instabilities of the transmitter and receiver carrier frequency oscillators, can lead to severe system degradation due to inter - carrier interference ( ici ). symbol timing synchronization must also be achieved in order to avoid inter - symbol interference ( isi )
其載波頻率誤差會引入子通道之間的干擾( ici ) ,而幀同步的誤差會引入符號間干擾( isi ) ,同時還會對通道估計帶來嚴重的影響。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。And pays emphasis on analyzing the system structure and system flow, the core techniques, the channel characteristic and parameters of dvb - t system. the system adopts some core techniques such as cofdm, a lot of tps ( transmission parameter signalling ) insert and guard interval, and so on. so it can withstand high - level ( up to odb ), long delay static and dynamic multipath distortion
論文首先描述了數字電視地面廣播的需求條件,技術難點和目前存在的問題,並重點分析了dvb - t系統結構流程,核心技術及系統通道特性和參數,該系統採用了cofdm (編碼正交頻分多路復用) ,大量導頻信號插入和保護間隔技術等核心技術,使之能抵抗高電平( 0db ) ,長延時的靜態和動態多徑失真,有利於數字和模擬電視的混合傳輸,它的多載波調制模式功能和性能在移動和便攜接收、同頻網等方面具有獨特的優勢。In the system, the low voltage power line is the first signal tunnel without any other relay equipments between customer terminal and substation collector, public telephone line serves as the second signal tunnel between substation and management center computer. as a breakthrough of conventional concept of electricity meter, this thesis initiate a new concept, namely, intelligent power customer terminal ( shortly, customer terminal ), which is developed with spread spectrum plc communication functional and possesses many advanced functions, such as, in addition to electric energy acquisition, guarding against electricity pilfering, preventing wrong connection, protecting malfunction, remote communication ( for example, remote power supply or halt, remote configuration of electricity meter, remote load control, etc ), and so on
本文首先系統地總結了目前國內外低壓電力網數據傳輸技術的研究現狀和存在的問題,在此基礎上,從理論上論證了在低壓電網上應用擴頻載波數據通信技術的可行性和優越性,並重點論述了擴頻載波技術抗電力線噪聲干擾的機埋;本文提出了一個新穎的基於低壓電力線擴頻載波通信技術的集中遠抄系統的總體方案,即由用戶終端、集中器和電能管理系統所組成的網路系統,其中,用戶終端到配變集中器用低壓電力線作為通道,中間無需其他硬體中繼設備,集中器到電能管理系統用公用電話網作為通道。The paper contains all kinds of knowledge related to the system, including maxwell electromagnetic theory, pattern of optical radiation in space, channel model of atmosphere communication, computer communication protocols, wireless lan communication protocols, medium access control protocol, carrier sense multiple access / collision detection protocol, manchester coding theory, pulse position modulation coding theory and so on
主要包括: maxwell電磁理論;發送光場模型;空間通道模型;計算機網路通信技術:無線局域網通信技術;媒體訪問控制規程( mac ) ;載波檢測多址接入碰撞檢測規程( csma cd ) ;曼徹斯特編碼與ppm編碼技術等。Over - the - horizon radar ’ s beam - frequency is high frequency band and its wavelength is so long that the annate ’ s characters are very complicated when applicated on the ship. the character of coupling between cells and the environment must be measured to compensate in the radar signal process step. the ship - based over - the - horizon radar uses cfa ( crossed field antenna ) as array antennas ’ cell
艦載超視距雷達使用高頻信號作為發射頻率,其波長較長,在艦船有限的空間內,陣列天線的陣元之間的耦合與陣元與背景之間耦合都十分嚴重,必須測量陣列天線通道的幅相一致性,作為雷達信號處理的補償參數。With the characteristics of large ambient noise, very narrow bandwidth, low carrier frequency, great propagation latency and time - space - frequency variant multipath effect ( mpe ), the stochastic ocean channel has demonstrated the greatest complexity and difficulty for underwater acoustic wireless communications. among them multipath effect ( mpe ) is the most difficult obstacle that results in signal fading and inter - symbol interference ( isi )
但是噪聲高、帶寬窄、載波頻率低、傳輸時延大、多途徑效應隨時間?空間?頻率變化等通道特性都會給有效、可靠的水聲通信帶來很大的麻煩,其中多途徑效應是最主要的困擾因素,它會導致信號幅度衰落和碼間干擾。Later, simulates the ofdm system by matlab software, researchs the effect about ofdm system by mapping, guard interval, sub - carrier and channel
然後通過matlab軟體對ofdm系統進行了模擬分析,研究了調制映射,保護間隔,子載波和通道對ofdm系統的影響,並得出了一些結論。To overcome the affection of ici and awgn on the ls estimate of the transfer function at pilot tones, the proposed bispectrum - based channel estimation algorithm employ the suppression of ici and awgn components in the received pilot signals by bispectrum and then the accuracy of the estimation is improved. with the channel estimation at pilot tones, an efficient interpolation is necessary. an improved interpolation method based on transform - domain filtering is proposed, which employs dft / idft and filtering in a transform domain so that the effect of noise on the equalization is significantly reduced
針對導頻處通道傳遞函數的ls估計中存在載波間干擾和加性高斯白噪聲的影響的這一問題,本文將傳統的ls估計方法與雙譜相結合提出了一種新型的基於導頻雙譜通道估計演算法,它利用了雙譜對高斯噪聲的抑制作用來減小接收到的導頻信號中的載波間干擾和加性高斯白噪聲的影響,從而提高了導頻子載波上通道估計的精度。It belongs to multi - carriers modulating technology, and its most remarkable character is the high - speed transmitting ability as well as the excellent resistibility to interface of signal interval and decline of channel selectivity
它屬于多載波調制技術,其最大的特點是傳輸速率高,對碼間干擾和通道選擇性衰落具有很強的抵抗能力。Secondly, optical nodes usually do not possess the ability of wavelength interchange for the restriction of cost and technology, optical network brings out so - called wavelength continuity constraint because connection must be established on the path that be carried by the same wavelength between source and destination nodes
再者,波長轉換技術和成本限制使得網路節點一般沒有波長轉換能力,源目的節點間的通信連接必須始終承載在同一波長通道上,產生了所謂的波長連續性限制。In case where long - range communication is needed, spatial diversity blind equalizer ( sdbe ) is an effective way to improve snr and suppress distortion. joint carrier phase recovery with sdbe using second order digital phase lock loop is presented to track the doppler shift, and a kind of quantization method is used to reduce the complexity of the multi - channel algorithm. its performance is very similar to the original one
模擬結果表明,採用二階數字鎖相環的空間分集均衡演算法的跟蹤性能超過了採用一階鎖相環和未加鎖相環的演算法,可有效補償由於水聲通道時變而引入的載波相位快速變化;採用誤差量化的演算法和原演算法的收斂和踉蹤性能都很接近。A group of orthogonal frequency carriers are used in ofdm system to improve the using rate of spectrum. if the orthogonal character can be held and ignore the inter - channel interference ( ici ), the symbol error character of ofdm depend on the modulate of source codes. this dissertation propose the theoretic formula of ofdm - qam and ofdm - psk in this precondition
為了提高頻譜利用率, ofdm系統使用了一組正交的子載波來傳輸信號,若能保證各子載波間的正交性不被破壞、不考慮通道間干擾( ici ) ,則ofdm系統的誤碼性能由信元調制方案的誤碼性能決定,文中推導了該情況下ofdm - qam和ofdm - psk的理論誤碼率公式。This paper gives an overview on the development of wireless communication and the orthogonal frequency division multiplexing ( ofdm ) technique. basic characters of wireless channel, transmission principles and signal frame structure design of ofdm are introduced. main non synchronization factors between ofdm transceivers are pointed out
本文介紹了無線通信與多載波正交頻分復用( ofdm )技術的發展概況,闡述了無線通道的基本特性、 ofdm的調制解調原理與信號幀結構的設計,指出了導致ofdm收發信機間不同步的主要因素。Space - time block codes ( stbc ) based on orthogonal design has attracts enough attentions in its applications in mimo - ofdm systems for its full diversity exploiting and low coding / decoding complexity. these applications include not only system performance improvement, but also reduction of the peak to average power ratio in mimo - ofdm systems. under these backgrounds, this paper first studies space - time block codes under the single carrier, flat fading situation, discusses the encoding / decoding principle and its performance under different channels. then, the author focused on the performance of space - time codes under time selective and frequency selective channels, uncovered the fundamental cause of how maximum doppler shift and power delay profile influences the performance of space - time codes through deduction and simulation
在上述背景下,本文以單載波,平坦衰落通道下的空時分組碼為切入點,深入分析了其編譯碼原理和在不同通道情況下的性能;以此為基礎,後文展開了對空時分組碼在多載波,時間選擇性和頻率選擇性衰落通道下的性能研究,通過理論推導和充分的模擬,揭示了空時/頻分組碼在時頻選擇性衰落通道中的性能變化的根本原因;在以上對多載波系統中空時分組碼的研究的過程中,作者發現了空時分組碼在降低系統峰平比方面應用的可行性,提出了一種降低峰平比的新方法。分享友人