頻譜選擇性 的英文怎麼說

中文拼音 [bīnpǔxuǎnzháixìng]
頻譜選擇性 英文
spectral selectivity
  • 頻 : Ⅰ形容詞（次數多） frequent Ⅱ副詞（屢次） frequently; repeatedly Ⅲ名詞1 [物理學] （物體每秒鐘振動...
  • 譜 : Ⅰ名詞[書面語]1 （按類別或系統編成的書或冊子等） table; chart; register 2 （指導練習的格式或圖形）...
  • 選 : Ⅰ動詞1. （挑選） select; choose; pick 2. （選舉） elect Ⅱ名詞（挑選出來編在一起的作品） selections; anthology
  • 擇 : 擇動詞（挑選） select; pick; choose
  • 性 : Ⅰ名詞1 （性格） nature; character; disposition 2 （性能; 性質） property; quality 3 （性別） sex ...
  • 頻譜 : frequency spectrum; frequency content; spectrum; power density spectrum; power spectrum; [系統] s...
  • 選擇 : select; choose; opt; election; choice; culling; alternative
  1. And then facing the problem of the channel estimation of the adaptive modulation system, we conclude out the channel estimation algorithms on maximum likelihood ( ml ) estimation and maximum a posteriori ( map ) estimation under the condition of flat fading channel and selective fading channel in detail. to meet flat fading channel, we simulate the relationship of the ratio between the error covariance in map estimation and ml estimation and pilot symbol message length. the conclusion can be drawn from these results

    接著，對自適應調制系統中的通道估計問題難點，詳細推導了平衰落通道條件下和選擇性衰落通道條件下最大似然（ ml ）估計和最大后驗概率（ map ）估計演算法，針對平衰落通道，我們模擬了map估計和ml估計的方差與導頻符號長度的關系，模擬結果表明，錯誤方差受多譜勒頻率的變化影響最大，並且對實際的自適應調制系統，導頻符號長度的取值超過20個符號長度時， map通道估計明顯優于ml通道估計。
  2. 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。
  3. Secondly, the wavelet transform of ae signals collected in experiment is carried out with db6 wavelet and scale 3 on the basis of the signal ' s frequency analysis. the high frequency d, signal is ae characteristic signal. and by choosing the level ' s wavelet coefficient as its input, the wavelet - neural networks can be trained with the data of ae experiment, and the ae signals can be effectively recognized

    然後，在實驗與對實驗所採集數據頻譜分析基礎上，根據對小波分析用於信號處理可行性研究，本文選擇db6母小波、尺度j = 3對實驗所採集數據信號進行小波變換，變換后其高頻成分d _ 1信號即為聲發射特徵信號。
  4. The potential applications of amr include both civil and military communication, especially non - cooperative communications and communication confrontation, such as identifying signals, supervising signals, distinguishing interference, electronic confrontation, analyzing military threat, etc. on the basis of our analysis to the existing research on feature abstraction, the related feature abstraction methods are optimized in this paper, resulting several effective methods such as the feature abstraction based on transformation domain, stepped voltage level analysis, normalized carrier - free spectral energy analysis, squared signal and fourth powered signal analysis, etc. both the decision theory based on recognition algorithms and the artificial neural network ( ann ) based on recognition algorithms is analyzed, and the former is selected as it is more appropriate for this research

    調制類型的自動識別廣泛應用於民用通信與軍用通信，尤其是對于非合作性通信、通信對抗，比如：信號確認、信號監控、干擾辨識、電子對抗、軟體無線電、電子救援、通信對抗、軍事威脅分析等。本論文在分析現有研究的基礎上，借鑒了已有的特徵提取方法，對相關調制類型特徵提取方法進行了優化，使用了一些有效的方法，如基於變換域特徵提取方法、梯層電平分析方法、剔除載波后的歸一化頻域能量分析方法、信號平方后的頻譜分析方法、信號四次方后的頻譜分析方法等。通過對基於決策理論和基於人工神經網路兩種識別演算法進行分析，本論文選擇了較適合的基於決策理論的識別演算法。
  5. In the terms of interpolation, the image reconstructed from nearest interpolation or linear interpolation has good edge but serious noise ; reconstruction from 4 * 4cubic interpolation or three b - spline or three - order lagrange interpolations has better local character. 2 x 2cubic interpolations which has both better edge and local character is the ideal interpolation, the following is the basic principle during reconstruction : ( 1 ) the more width of interpolation, the more number of summation and the more order of interpolation polynomial, the higher of density resolution ; ( 2 ) the more of interpolation polynomial and width of interpolation, the more of reconstruction time simultaneously, aimed at eliminating the effects of noise contained in projection data, in this paper, author analysis cause and effects of common artifacts. importantly, discusses convolution back - projection reconstruction algorithm with a shift axis of rotation has been derived for correcting images that acquired with a divergence axis of rotation using the fan beam geometry with an angle - equaled detector

    在ct圖像重建時，選擇有限帶寬窗有較好的空間解析度，三角形窗有較好的密度解析度，選擇餘弦窗則使得空間解析度與密度解析度的折衷；從窗函數的頻譜角度來講，可以用於圖像重建的一個良好的卷積窗函數應該具備以下條件： （ ? ）小的3db帶寬b ，即最小的主瓣寬度； （ ? ）最小的旁瓣最大峰值a ； （ ? ）最大的旁瓣峰值衰減速度d ；就內插函數而言，臨近點內插與線性內插重建圖像噪聲大，但有較好的邊緣與細節； 4 4三次內插、三次b -樣條與四次拉格朗日多項式內插圖像平滑，局部特性較好。
  6. According to the theory of digital signal processing, discrete fourier transform has selectivity to frequency just as spectrum analyzer

    根據數字信號處理理論，離散傅里葉變換（ dft ）演算法對頻率具有選擇性，有相當于頻譜儀的功能。
  7. In addition, the author puts forward that the eggs could be recognized based on the difference in the frequencies of their prompted sounds. because the eggs " prompted sounds are lied on low frequency bands, the microphone and sound amplifier that have excellent duration response should be used. the output signal from the sound amplifier is transferred to data signal by a / d card before it is put into computer

    蛋品激勵出的聲音主要集中在低頻段，因此選擇在低頻段有好的頻率響應特性的麥克風和放大電路；放大輸出信號通過a / d採集板變換成相應的電壓數值信號送入計算機，對離散的信號數據進行傅立葉變換得到它的頻譜圖和各頻段能量分布圖；而後將能量分佈特徵數據作為神經網路的輸入值，這樣，好蛋和破損蛋的模型就建立起來。
  8. The optimal length of crystal was achieved for the characteristics of quasi - three - level. three types of crystal were compared, we select lbo as the main frequency doubler. meanwhile, the other strong spectrum were restrained by suitable coating

    從激光晶體的準三能級特性出發，充分考慮增益與損耗之間的矛盾，選擇出最佳晶體長度；對三種倍頻晶體進行了比較，選擇出lbo作為主要倍頻晶體；對膜系進行了必要的分析，在維持946nm譜線振蕩的同時，充分考慮了其它激光譜線的抑制。
  9. In mimo systems, the signal can be sent and received through multiple antennas or antenna arrays. the combination of ofdm and mimo can effectively alleviate the problem of multi - path propagation, increase system capacity, and obtain more robust system capability, so they are considered as the main stream techniques of the future wireless communication system

    Ofdm技術固有的抗通道多徑和頻率選擇性衰落特性以及mimo在提高系統頻譜利用率，改善無線通信系統性能等方面的巨大作用，使得這兩種技術的融合成為了下一代移動通信系統的必然選擇。
  10. The influences of bus - connected networks, different monitoring points, low voltage windings and types of neutral point grounding on the frequency responses of pd signals are analyzed which give suggestions for the selection of monitoring band and monitoring points and pd localization

    分析了繞組的外聯網路、不同的監測點、低壓繞組、中性點接地方式等對局放信號幅度、頻譜的影響，為局部放電在線監測頻帶、監測點的選擇以及局放的定位提出了具體的建議。
  11. In this thesis, spectral method is used to analyse the scattering characteristic of frequency selective surfaces ( fss )

    本文用譜域方法研究了頻率選擇表面（ fss ）的散射特性。
  12. After compared these methods, power spectral frequency band intensity, pca and linear network were choose to carry out the recognition system. finally, this paper provided software of gui as well as a group of simulink blocks to operate data and acquire results

    在綜合比較各種方法后，最終選擇功率譜估計頻帶強度為分類特徵， pca用於特徵提取，線性神經網路作為分類器用於系統的實現。
分享友人
分享到 Line

分享到臉書