signal fading 中文意思是什麼
signal fading
解釋
信號衰減-
Polarization diversity and maximum ratio combining ( mrc ) is used to restrain the sharp signal fading in the telemetry systems, in which the object is in flight at a high speed and rotating and in low elevation
在信號極化衰弱現象嚴重的環境中對快速飛行目標、低仰角運動目標以及旋轉運動目標等進行遙測接收時，極化分集最大比合成技術可以有效的改善接收性能。 -
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。 -
3. studying still image transmission systems without channel coding or with turbo codes over both awgn and rayleigh fading channels by matlab simulation. simulation results show that turbo codes not only advance the dependability of communication systems, but also reduce channel signal - to - noise ratio ( snr )
將turbo碼應用於靜止圖像傳輸系統，信源編碼採用矢量量化編碼，分別在awgn通道和rayleigh衰落通道下，對不採用通道編碼和採用turbo碼作為通道編碼的各種情況進行模擬。 -
The following algorithms have been proposed and tested in the thesis : 1 frequency selective fading : combine the isomorphism between the input space and the output space and propose a new approach to blind equalization of the channel. compared with conventional methods, the new approach offers lower computational complexity, better performance, and more robust against the over - determination of the system order ; 2 time selective fading : a new approach to the equalization of time selective channel based on the zero - forced equalizer is proposed which is more simple in its structure of algorithm ; 3 time - varying channel : using the instantaneous mean value changes of the output signal to extract the information of channel variations and model it using ar model, kalman filter is then employed to track channel variations, it bears faster ability in tracking the variation of tv channels ; based on the isomorphism between the inputs and the outputs and some of the approaches using in mimo system, a new algorithm of equalization of simo time - varying channel is proposed, which also share the merits of being robust against the over - determination of the system order ; model the time - varying channel using the multi - resolution decomposition wavelets, and then a blind identification method based " on the model is proposed ; at last, a new model for equalization and identification of mimo system is proposed
主要工作在以下幾個方面： 1 、針對頻率選擇性衰落通道：結合輸入輸出空間同構關系提出一種新的頻率選擇性通道均衡方法，與傳統方法相比，該方法計算量更小，收斂速度更快，性能更優，且對系統階次的過確定表現穩健，具有實際均衡應用價值； 2 、針對時間選擇性衰落通道：提出一種基於迫零均衡的時間選擇性通道均衡方法，演算法結構簡單； 3 、針對時變色散通道：利用瞬態均值曲線提取通道時變信息，對之ar建模，利用卡爾曼濾波器跟蹤時變通道抽頭變化，可以快速跟蹤通道變化；基於輸入輸出空間之間的同構關系以及多輸入多輸出系統的處理方法，提出了新的單輸入多輸出色散時變通道均衡與識別演算法，同樣具有對通道階次過確定保持穩健的優點；結合小波多解析度分析提出一種基於小波模型的通道盲識別演算法；研究時變的多輸入多輸出系統的盲均衡與盲反卷積問題，給出一種時變系統處理模型。 -
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。 -
It is very difficult to design a high - quality underwater acoustic data transmission system. in our study, we use frequency diversity and frequency - hopped technology. this method is an effective solution for the isi and signal fading
該方法起到保證mfsk傳輸系統使用頻率中文摘要統使雨頻率分集技術能得以有效的實現；並可用於提高mfsk信號檢測精度，因此在頻率信號檢測中它有廣泛應用意義，它是本文重要創新之處。 -
Several key factors such as signal fading and multi - path effect are further analyzed and simulated. summarizes smart antenna algorithms for cdma mobile terminal
在總結應用於cdma移動終端的智能天線演算法基礎上，提出一種利用接收信號與期望信號相關特性的新型智能天線演算法。 -
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。 -
In wireless communication system, signal fading arising from multipath propagation is a particularly severe channel impairment that can be mitigated through the use of diversity
在移動通信系統中，由於多徑傳播引起的衰落對通道產生的嚴重影響可以通過分集技術得到有效的解決。 -
Even though most losses in wireless networks stem from factors like signal fading, interference, and link blackouts, tcp assumes the losses to be related to congestion, so it kicks in algorithms that slow down network traffic
盡管無線網路中的大多數損耗來自信號衰退、干擾以及連接中斷等因素，但是tcp假定這些損耗與擁塞有關，因此它摒棄了降低網路流量的演算法。 -
On the every different application environment, this system must adopt the effective, advanced and applied technology to reject signal fading caused by mai, mutipath and near - far effects, and also to solve the corresponding problem existented at the practice communication
在各種不同的應用環境情況下，這個系統必須採用有效的、先進的和實用的技術抑制由於多址、多徑及遠近效應引起的信號衰落，並且要不斷解決實際通信中存在的相應難題。 -
Then the signal fading problem of the sensor arising from environmental effects is presented and several solving methods are introduced. at last, we choose the closed loop controlling working point method to stabilize the sensor ’ s working point because of its ’ high sensitivity and simple structure
研究了外界環境變化引起的干涉儀輸出信號衰落問題，在比較幾種常見的解決方案后，選用靈敏度高、結構簡單的閉環控制工作點演算法來穩定干涉儀的工作點。 -
So the acoustic wave is the only practical solution in this channel. an underwater acoustic channel is characterized as a multi - path channel due to signal reflections from the surface and the bottom of the sea. because of wave motion, the signal multi - path components undergo time - varying propagation delays that result in signal fading and inter - symbol interference ( isi )
本文從分析淺海水聲通道的傳輸特性入手，針對多途徑效應引起的幅度衰落及碼間干擾問題，提出一種適用於水聲e - mail通信的十六進制（或八進制）數字頻移鍵控（ mfsk ）傳輸系統。 -
It has been proven that the spread spectrum technologies have good capabilities of overcoming isi in electromagnetic wireless channel. the feasibilities of their applications to underwater acoustic channel have been analyzed, the frequency hopping technology is chosen. instead of using time - frequency diversity, convolutional coding and viterbi decoding are employed to combat signal fading, consequently the bit - rate and bit - error - rate performance of the underwater acoustic voice communication system can be balanced and controlled
由於擴頻技術在抗碼間干擾方面具有優良的特性，因此在分析了各種擴頻技術于本研究應用的可行性之後，確定了跳頻技術作為具體實現方案；在克服幅度衰落方面，選用卷積編碼和維特比譯碼方法來替代原有的分集技術以綜合調節系統的通信速率與誤碼性能，達到差錯可控的目的。 -
Because of the affection of noise and signal fading, in order to high data rate access and high quality, wireless communication need new technology to improve the link reliability and enhance the spectrum efficiency. mimo ( multiple input and multiple output ) can enhance the spectrum efficiency and increase channel capacity greatly, and reduce the multipath affection without spectrum band and power increasing. the 3th generation mobile communication wcdma is coming, with the purpose of putting mimo, stbc ( space time block coding ), space diversity into practice of wcdma systems, in order to lay the foundation of 3g toward 4g, this dissertation has done some research under this background
在發射機和接收機使用多個天線進行數據傳輸的多輸入多輸出（ mimo ）技術，可以在不增加帶寬和天線發送功率的條件下，成倍的提高頻譜利用率，提高系統的通道容量，還可以抗多徑干擾。第三代移動通信wcdma即將到來，為了將多天線技術（ mimo ） ，空間分集技術，空時編碼技術用到wcdma系統中去，為第三代移動通信向第四代移動通信系統平穩過渡奠定一定的基礎，需要做一些理論上的研究。
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