衰落信號 的英文怎麼說
中文拼音 [shuāilàxìnháo]
衰落信號
英文
fading signal-
In chapter 4, a simulation approach is presented, which combines the outdoor radio propagation model, the eigen - driven patterns of handset diversity antenna with two feed ports and combining schemes of receiving signals, to investigate the performance of a dual antenna handset under co - channel interference ( cci ) and multi - path fading environment
第四章首先用本徵激勵方向圖的概念來產生手機雙埠分集天線的接收信號矢量,然後將其與城市室外電波傳播模型、分集合併方式相結合,建立了分析在具有共道干擾和多徑衰落環境中手機雙天線系統的性能模型。Lt is well anown that the multi ? ath effeet results in signal fading and intersymbol interference ( isd, wnich causes great difficulhes in pewces of transndssion in underwater acoushc cotnmnication. in this papef we used frequency diversity method to overcome the problem of signal fading, and used the frequency - hopping method to ebonate the isi caused by multi - path
水聲通道多途特性引起的信號衰落和碼間干擾是影響水下通信質量的主要因素,採用頻率分集技術可以處理幅度衰落,而跳頻技術則可以簡單、有效地抗多途引起的碼間干擾。Diversity receiving technique for synchronous time spreading signal in time - varying fading channels
時變衰落通道中同步時間擴展信號的分集接收技術When the doppler frequency shift is big and the rayleigh fading is serious, it would affect the despread and demodulation algorithm of the signal badly
當多普勒頻移較大,瑞利衰落嚴重時,將嚴重影響信號的解擴解調。Combined with the data - selected schemes proposed, the computational complexity of this method can be lowered. the performance of the presented rls method is analyzed by simulations, and it is shown that this method is interesting for application. 4 time - selective channel signal model based on multipath - doppler diversity representation is given in multi - path fast fading channel, and rls space - time receiver algorithm based on time - varied constraint condition is presented and the computational complexity of this method is analyzed
4 、針對多徑快衰落通道下的ds - cdma系統,給出了基於多徑-多譜勒觀點描述的1百安電弓卜科東兔j憶學協士學位論文時間選擇性通道的信號模型,提出了基於變約束條件下的遞歸最小二乘空時接收機演算法並分析演算法的運算量,最後通過模擬分析了所提出的方法的性能。We propose the joint filterbank precoders and decision feedback equalizers structure at first, by which the dispersive channel is equivallent into parallel independent flat fading subchannels such that the diversity gain of the receiver is increased. then we adopt the discrete - time ( dt ) canonical model to convert the problem of blind signal processing of tv dispersive channels into processing the time - invariant multi - channels model blindly, and discuss the problem of blind equalization and identification of tv dispersive channels based on this new model
第一種是採用濾波器組聯合均衡方法將色散通道等價為一組獨立的平坦衰落子通道,以提高接收機的分集增益;另外一種是提出採用離散正則模型將時變色散通道的盲信號處理轉化為時不變多通道模型的盲信號處理,並針對該模型對時變色散通道的盲均衡與盲辨識方法進行了詳細討論。When transmitting signal is below 500 kbps, increasing the system power can reduce the bit error rate ( ber ) for the signal suffering only flat fading
當碼速率較低時( 500kbps以下) ,信號受到平坦衰落,增大系統功率可以降低系統誤碼率。But when the bit rate is above 1 mbps, the signal suffers frequency select fading, which causes the serious intersymbol interference ( isi ). increasing the system power can ’ t reduce the ber
但是當碼速率提高到1mbps以上時,信號受到頻率選擇性衰落,碼間干擾嚴重,增大系統功率也不能降低系統誤碼率。The problems of carrier frequency offset estimation under the condition of the agwn channel, frequency flat - fading channel and frequency selective - fading channel are studied in detail respectively
本文仔細研究了在高斯白噪聲通道下、頻率平坦衰落通道下和頻率選擇性衰落通道下高精度估計信號載頻偏差的問題,並對相應演算法提出了一些改進辦法。In this thesis we analyze in detail the influence, created by random change of the optical wave polarization, on the output of the interferometer. then several principles of eliminating polarization - induced fading are introduced, and the principle that inserting two faraday rotator mirrors into the end of michelson fiber interferometer to eliminate the fading is analyzed in detail. this method can eliminate polarization - induced fading without additional signal processing, and make the output of the sensor stable
其中,本文詳細分析了光波偏振態的隨機漂移對干涉儀輸出的影響,介紹了目前幾種消偏振衰落技術的原理,著重討論了在光纖michelson干涉儀末端加兩個法拉第旋轉鏡的消偏振衰落的原理,該方法不需要任何附加的信號處理就可以消除偏振衰落,使干涉儀輸出穩定。Because of the different time delay among multi - paths, the received signal undergoes frequency - selective fading
由於多徑干擾之間具有不同的時間延遲,接收信號將承受頻率選擇性衰落。Multipath fading signal analysis with wavelet and fractal theories
基於小波和分形理論的多徑衰落信號分析Contributions in this paper mainly sh ow four points : 1 the structure characteristic of the received ds - cdma signal is analyzed in the presence of multi - path slow fading effect case for wireless mobile communication. according to this characteristic, four data - selected schemes based on chip - matched filter are presented from the perspective of energy and structure of signal. and the impact of these schemes on multiple - access interference ( mai ) and inter - symbol interference ( isi ) is analyzed
本文的主要貢獻在於四個方面: 1 、針對無線移動通信系統中廣泛存在多徑慢衰落效應的情況,分析了ds - cdma系統中接收信號本身的結構特徵,根據這個特徵,在匹配濾波的基礎上,從能量與信號結構的角度提出了四種不同的數據採用方案,並分析了不同數據方案對多址干擾與碼間干擾的影響。Underwater acoustic communications ( uwa ) are made difficult by the combined effect of multipath propagation and high temporal and spatial variability of the channel conditions. the fading which was caused by multipath propagation was one of the main factors influencing the performance of underwater acoustic communication systems
水聲通道中廣泛存在的多徑傳播效應是水聲通信所面臨的主要障礙之一,由多徑所產生的信號衰落效應是影響水聲通信系統性能的主要因素之一。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。Abstract : in this paper, an orthogonal multicode wideband cdma system modelincluding pilot channel based on chaos spreading sequences is given. based on chaos sequences, with pilot channel inserted orthogonally, it is shown that the performance of the system is improved. the performance of the system in fading channel is analyzed
文摘:提出一種基於混沌序列含導頻信號的寬帶正交多碼cdma系統模型,利用混沌序列以及採用正交插入導頻信號提高系統性能,並對此模型在衰落通道中的性能進行分析。This model has the ability of analyzing the effects of some key system parameters, such as the signal correlation coefficient, speed of the mobile, and the update rate of combining weights, on the system performance
研究了信號相關系數、移動臺運動速度、通道衰落率,以及合併權值更新速度對合併性能的影響。Civil air defense alarm system was a system to dispense antiaircraft alarm sig - nal, hand hostile air attack informational communication to urbanite at wartime. it is a particular informational communication system of the civil air defense depart - ment, and can not be taken place. at the development trend of digitaliza - tion, unitization, integration of civil air defense communication, the civil air defense alarm system is developing too, for adaptation to the require of both future war and peaceful dual, and enhancing civil air defense communication system ' s directing automation. in recent years, development of different kinds of communication technology infuses new clearly energy into communication, especially spread spectrum communication, because of its strongly interference - free feature, invisibility best, realizable code division multiple access and antimultipath wane and so on merit, gets extensive use at wireless region ; the corresponding spread spectrum chips emerge as the times and get boom, which provides advantag e to realization of the circuit of spread spectrum communication. at the same time, in company with the advance of electronics level, the single chip microcomputer has a great development, world renowned chip manufacturer pushout respective products one after another, the kinds of which are too many to statiste
在人防通信的數字化、一體化、綜合化必然的發展趨勢下,人防警報系統也不斷發展,以適應未來戰爭和和平時期的雙重需要,提高人防通信系統指揮自動化。近年來,各種通信技術的發展給通信注入了活力,擴頻通信更因其抗干擾能力強、隱蔽性好、可實現碼分多址和抗多徑衰落等優點在無線領域得到了廣泛應用;其相應擴頻處理晶元應運而生並得到迅速發展,這為擴頻通信的電路實現提供便利。同時隨著微電子工藝水平的提高,單片微型計算機有了飛躍發展,世界上著名的集成電路晶元製造商紛紛推出各自的產品,單片機型號之多,已達到難以統計的地步。The underwater acoustic channel is very complex where cochannel interference, doppler frequency offsets, narrow bandwidth and time and frequency selective deep fades obstructs the development of high speed and fidelity underwater data transmissions. thus projects of high speed and fidelity underwater signal transmissions become a hotspot in the fields of world academic circles. the conventional serial communication must use adaptive equalizer to combat the multipath in real - time
海洋水聲通道是一種極其復雜多變的時-空-頻變參通道,其通道窄,強多途干擾,信號起伏衰落嚴重,一直是水下信息可靠高速傳輸的主要障礙,因此如何在水聲通道中高速率準確地傳輸數據,就成為世界性的熱門課題。The assumption that the channel is known is questionable in a rapidly changing mobile environment, or when multiple transmitter antennas are employed. unitary space - time codes and differential unitary space - time codes do n ' t need any channel information. we discuss the unitary space - time codes briefly and study the details of the dustc, including the fundamental differential transmission and receiver equation, and parameters searching algorithm. the parameters searching and simulations results is proposed
酉空時編碼及酉差分空時編碼( dustc )都不需要通道信息,著重研究了酉差分空時編碼技術,簡要說明了酉空時編碼的信號形式及星座設計方法;分析了dustc的發送和接收公式,分析了dustc的嚴格pep和sep的聯合界,給出了當snr值在不同的范圍時, dustc星座參數的選取準則,並進行了rayleigh衰落通道的模擬。分享友人