radio wave fading 中文意思是什麼
radio wave fading
解釋
電波衰落-
However, the radio wave can then reflect back of the earth and become refracted again to return earthwards once more. this can sometimes occur a number of times with little attenuation but some fading
在雷達探測中可以利用此方法，初步確定雷達回波中哪個地區會出現陷獲折射回波，為進一步分析從雷達回波反演大氣層結提供了可能。 -
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。 -
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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