短時衰落 的英文怎麼說

中文拼音 [duǎnshíshuāilà]
短時衰落 英文
short time fading
  • 短 : Ⅰ形容詞（空間、時間兩端之間的距離小） short; brief Ⅱ動詞（缺少; 欠） lack; owe Ⅲ名詞1 （缺點） we...
  • 時 : shí］Ⅰ名1 （比較長的一段時間）time; times; days:當時at that time; in those days; 古時 ancient tim...
  • 衰 : 衰動詞（衰弱） decline; wane
  • 落 : 落名詞[方言] （北方對蓮花落的俗稱） a kind of folk song
  • 衰落 : decline; be on the wane; go downhill; fading; decay; decaying; lapse; erode
  1. 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。
  2. This thesis analyzed the error performance of mfsk and mpsk modulator in hf with optimal receiver, studied the shortcoming and strongpoint of several typical short - wave data transmission systems and their performance over fading and intersymbol interference channels. the theory and key technical of adaptive modem is discussed. in the last, an efficient modulation scheme - block coded modulation is introduced into hf radio systems to improve the efficiency of hf data transmission, this paper also proposes a hf data transmission system scheme composed of a block coded modulator and a decision feedback type adaptive equalizer

    本文在對短波數傳兩種常見調制方式fsk及psk最佳解調性能分析的基礎上，討論了幾種採用典型調制技術的短波數傳系統（如時頻調制、多進制頻移鍵控慢跳頻、 chess系統）原理、優缺點以及抗衰落和抗符號間干擾的性能；分析了自適應串列數傳系統抗短波通道衰落和多徑干擾的原理、關鍵技術；在本文的最後引入一種有望解決短波數傳系統低效率狀況的調制方式bcm -分組編碼調制，給出了一個採用bcm技術與自適應均衡技術相結合的短波數傳系統方案，並通過計算機模擬進行了初部驗證。
  3. 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。
  4. The result shows most of track and field items are at low ebb in china, and most of preponderant items being potential haven ' t the strength to compete with the master - hands of olympic games in a short time

    研究結果表明，我國田徑競技水平的發展態勢落後于奧運會，多數項目呈衰退態勢，而我國大部分潛在的優勢項目在短時間內還不能具備與奧運會強手相抗衡的實力。
  5. Rtce is based on forecasting the inherent vulnerabilities to propagation of hf time - varying channel, including multipath delay, doppler spread, selective fading, interference, so this paper also introduces characteristics of hf channel in the beginning. familiar rtce systems all adopt envelope method that bello brought forward

    實時選頻技術是基於對短波電離層時變通道固有的不利於電波傳播的各種因素，包括通道的多徑展寬、多普勒展寬、選擇性衰落、噪聲干擾等的預測的基礎上實現的，所以在開篇對短波通道的特點進行了詳細的介紹。
  6. Simulator presented in this paper provides a direct interface for the test of shortwave communication system, which well represents various features of hf channel such as multi - path delay, rayleigh fading, doppler shift, doppler spread, gaussian noise and impulsive interference, etc. in order to realize the channel simulation for the intermediate frequency signal, we, inspired by the idea of soft - defined radio, bring forward a new design method that the channel simulator consists of several dsp chips

    本文研製的模擬器提供介面直接對短波通信系統進行測試，能夠全面反映短波通道的多徑時延、瑞利衰落、多普勒頻移、多普勒擴展、高斯噪聲和脈沖干擾等特性。為了實現對中頻信號的通道模擬，開發出一個結合軟體無線電思想的由多個數字信號處理晶元構成的短波通道物理模擬器。
  7. This thesis adopts 8psk / qpsk modulation mode that ' s widely applied in short - wave communication to research all - digital blind receiver in burst mode based on software radio technology. then related solutions are given for the doppler frequency shift problem and multiple fading problem in short - wave channels. the arrangement of the thesis is below : chapter 1 gives brief description for the new technology and new systems of short - wave communication and for the development and appliance of software radio

    本文採用短波通信中應用廣泛的8psk qpsk調制方式，研究基於軟體無線電技術的突發模式全數字盲接收機，並對多音并行及慢速傳輸中存在的多譜勒大頻偏問題、單音串列、高速數傳時在短波通信鏈路中發生的干涉衰落問題做了研究，提出了相應的解決方案。
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