頻譜限制 的英文怎麼說

中文拼音 [bīnpǔxiànzhì]
頻譜限制 英文
spectrum limitation
  • 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）...
  • 限 : Ⅰ名詞（指定的范圍; 限度） limit; bounds Ⅱ動詞（指定范圍, 不許超過） set a limit; limit; restrict
  • 制 : Ⅰ動詞1 （製造） make; manufacture 2 （擬訂; 規定） draw up; establish 3 （用強力約束; 限定; 管束...
  • 頻譜 : frequency spectrum; frequency content; spectrum; power density spectrum; power spectrum; [系統] s...
  • 限制 : place [impose] restrictions on [to]; astrict; restrict; limit; confine; shut down on [upon]: 限制...
  1. The present shortage of radio spectrum results in large part from the cost and performance limits of legacy hardware established during the past century

    目前無線電頻譜壅塞的現象，大多起因於上個世紀製造的老式硬體設備在成本與效能上受到限制。
  2. With dispersion, xpm can induce intensity fluctuations and timing jitter of the pulses in the receiver. it can also cause the spectral spreading of the channel so that crosstalk is introduced. all these effects put a tight limit on the capacity of the systems

    它與色散共同作用，會導致接收端光脈沖的變形（強度起伏） 、光脈沖的時間抖動以及通道的頻譜擴展，這些後果都會限制系統的性能。
  3. Dttb ( digital television terrestrial broadcasting ) is one of the present digital television broadcasting modes, whose transmission media is earth. after a decade of intense research and development, the standards of digital television satellite broadcasting and digital television cable broadcasting have been confirmed. but the standard of digital television terrestrial broadcasting is still in disputation, for its transmission environment is rather awful, its spectrum resource is very limited and its service required is disperse, so it is potential to be improved in many aspects

    數字電視廣播發展近十年來，衛星和有線電纜廣播的基本傳輸體制已確定，而地面廣播由於傳輸環境惡劣，頻譜資源有限，應用需求分散，其標準在各國仍有極大的爭議，因為目前沒有一套標準能解決實際地面傳輸中的所有問題，因此數字電視地面廣播在許多方面都有很大的改進潛力。
  4. Compared with the traditional methods of artifacts elimination, ica, a kind of spatial filter, does not be restricted by the case of spectrum overlapping, and have a good reservation of useful detail signals

    此外， ica這種空間濾波器不受信號頻譜混迭的限制，消噪的同時能對有用信號的細節成分做到很好的保留，很大程度上彌補了時頻域方法的不足。
  5. By theory and practice simulation, the several types of constant envelope modulation techniques are analyzed and compared, including theirs modulation principle, phase path, the modulated wave envelope, power spectrums, error bit rate and the influence of its power spectrums of the band - limited and non - linear, etc. especially we have researched the ijf - oqpsk modulation technique, and the performance of its inter - symbol interference and time jitter free, and its strongly resisting of spectral spreading

    結合理論和實驗模擬結果，分析討論了衛星通信中的各種恆包絡調制技術，對它們的調制原理，相位路徑，已調波包絡，功率譜密度，誤碼性能，以及帶限非線性通道對其功率譜的影響等方面都作了研究和比較。特別研究了ijf ? oqpsk在消除碼間干擾和定時抖動方面的性能及其優良的旁瓣特性和抑制頻譜擴展特性。
  6. From the research of ijf - oqpsk, we draw the conclusion that, compared with bpsk, qpsk and msk modems, in the band - limited and non - linear channel, it has nearly constant envelope, less spectral spreading, better pe performance and the less interference of the adjacent channel, et. so, it is more suitable for the satellite communication channel

    通過對ijf ? oqpsk的分析研究可知，它相對于傳統的bpsk和qpsk調制方式，在帶限非線性通道下，具有包絡近似恆定，頻譜擴展小， eb no惡化小，對鄰道產生干擾弱等優點，因而它更適合於衛星通道。
  7. From theoretical analysis, we know the existing demodulation methods have limitations as following : one is that the subtraction of the two signals frequencies will display as the result of demodulation when we demodulate two time - domain adding signals without modulating information ( fault information ) ; the other one is that aliasing phenomenon will occur as a result of getting absolute value, detection or square in the process of generalized demodulation analysis, such phenomenon will result in some superfluous frequency composition on the frequency spectrum, which will puzzle the detec tion of mechanical vibration. if the sampling frequency is selected from a suitable range, the aliasing phenomenon will be avoided ; the last one is that aliasing frequencies will be produced in zoom demodulation analysis because this algorithm cannot employ digital low - pass filtering to avert the folding frequencies of higher harmonics in the process of zoom sub - sampling

    現有的解調分析方法存在以下三種局限性：將不包括調制信息（故障信息）的兩時域相加信號，也以其頻率之差作為解調信號而解出；廣義檢波濾波解調分析中，由於取絕對值、檢波或平方過程可能產生混頻效應，在解調譜中表現為無法分析的頻率成分，並由此推導出避免這種混頻現象的采樣頻率的選取范圍，從根本上避免此類誤診斷的產生；幾種細化解調分析新演算法中，因為無法在細化分析的選抽時進行數字低通濾波，有可能會出現調制頻率的高次諧波成分發生頻率混疊而反折到低頻部分的現象。
  8. Comparing with the traditional phase - shifted laser range finder, the method could implement the ranging with multifrequency by using single modulated frequency. it could not only solve the contradiction of the range and the precision, but has high degree of accuracy and wide range, simplify the hardware design, and reduce the cost. this paper introduced the theory of phase distance measurement, analyzed various testing methods and expatiated the hardware and the software for the proposal system

    與傳統的相位法測距相比，本方法使用單調制頻率實現了多頻測距，有效地解決了相位法測距中測程與測量精度之間的矛盾，具有高精度、大量程、大噪聲容限的特點，而且簡化了硬體設計，降低了成本；其次在數據處理中採用數據加窗函數的方法，提高了方波信號的頻譜解析度，進而提高了測量的精度。
  9. " the country dtt technical standard of china and frequency plan coordination with mainland authorities are interrelated issues. these technical issues are important because they affect the consumers as well as the success, or failure, of the future dtt industry, " said hoi - ying ( h. y. )

    亞洲電視有限公司高級副總裁鄺凱迎先生在今日（二月二十八日）的記者會上表示：中國內地採用的數碼地面電視制式，以及與內地機關的頻譜規劃協調是息息相關的議題。
  10. It shows that a disadvantag ekists when a crsi is used to measure a step structure in a wavefront, but it is useful to adjust a crsi system with lcslm. 4. according to the didriction effect of an aperture, the spatial resolution of our crsi was analyzed and the transform function of our crsi was calibrated by using the psd method of a step wavefront. and some factors which are associated with the accuracy of our crsi were analyzed too

    四、從光學系統衍射效應的角度分析了本文建立的環路徑向剪切干涉儀的空間解析度，並利用波前功率譜密度的概念對該干涉儀的空間頻率響應特性進行了標定，分析了限制該干涉儀測量精度的主要因素以及徑向剪切比與測量精度的關系，並指出了該干涉儀的測量范圍，結果顯示該干涉儀基本上可用於準確測量中低頻段的波前畸變。
  11. First of all, the algorithm base on the boundary problem of helmholtz equation and finite - difference technique, calculate the field in “ cold ” cavity and disperse the helmholtz equation, as a result of the formula : ax = x. secondly, according to the eigenvalue of matrix theory and applied iterative methods, eigenmode adopt a numerical approach which allows the improved chebyshev polynomial iteration which based on the power method to extract the isolated eigenmode in the spectrum. finally, we resolve the problem of compatibility in software and insert the eigenmode module into the chipic which will have the function of eigenmode analysis

    具體的說: （ 1 ）首先以電磁理論中的亥姆霍茲方程的邊值問題理論和計算電磁學中的有限差分法為基礎，計算冷腔中的場分佈並離散亥姆霍茲方程，得到標準的本徵值問題: ax = x ; （ 2 ）然後根據矩陣理論中的eigenvalue問題和數值計算中的迭代方法，採用改進后的chebyshev多項式，在power迭代法的基礎上對ax = x進行多項式迭代，實現對頻譜中孤立本徵模的萃取; （ 3 ）最後將用fortran語言編制的eigenmode模塊加入到chipic軟體中，解決了eigenmode模塊與chipic主代碼的兼容問題，從而實現了chipic軟體的模式分析功能。
  12. E there is one - to - one map between the mathematical formulation and circuit realization, and that the method is systematic and suited for designing the network function with zeros and high - order filter. at last, the limitation and applied fields of the methods for realizing one - dimension cwt based on state - space log - domain filter are pointed out, it is also proved by the theoretical analysis and calculation results that the methods are suited for synthesizing the wavelet functions with very small scale or the frequence - transloction version of the mother wavelet ( with much translocation in frequence - domain )

    論文還給出了用狀態空間對數域濾波器實現一維連續小波函數的限制條件，並指出了這種實現方法的應用范圍，理論分析與計算結果表明該方法適合用於實現尺度很小的小波函數或由原基小波經頻譜搬移（搬移程度較大）后的小波函數。
  13. Subject to spectrum or other physical constraints, there should not be a ceiling on the number of licences to be issued for television programme services carried on dtt multiplexes ( paragraph 6. 9 )

    基於頻譜或其他實質因素的限制，以數碼頻道傳送的電視節目服務，不應為發牌數目設上限。 （第6 . 9段） 。
  14. Formulate policy guidelines for the efficient use of hong kong s scarce commodity - - terrestrial frequencies, especially what the government would intend to do with the spectrums once analogue had been switched off

    政府應為有效使用香港有限的頻譜而制訂政策指引，尤其是當模擬廣播終止后頻譜會如何利用等。
  15. The iboc technology, as proposed by the us - based ibiquity digital corporation, is also known as hd radio. it is designed to operate in the existing am and fm bands by attaching digital data to the sideband of analogue signals. the attached segment can either be a separate radio channel or other data

    Iboc是美國ibiquity digital corporation所推廣的制式，又命名為hd radio ，它被設計成可以在現行的am和fm頻帶內運行，在模擬訊號的邊旁加上數碼訊號，它可以是電臺聲音廣播或是其它的數據，但由於頻寬的限制，最大約是200kbps系統設計雖然善用有限的頻譜，但技術上較為覆雜，目前正發展第二代產品。
  16. By studying the discrete fourier transform properties of the band - limited digital signal, the authors introduce alternating projection neural networks into the paper, expand apnn ' s application scope from real field to complex field, and present several important conclusions on apnn. analyzing and discussing network ' s tolerance to noise, convergence rate and the spectral leakage problem of the truncated signal expected to be extrapolated by using these conclusions, the paper presents an extrapolation algorithm for band - limited signals based on alternating projection neural networks. a lot of simulation experiments show that the algorithm is effective. in addition, the algorithm is also effective to spectrum extrapolation. owing to adopting network structure, the algorithm is prone to parallel computation and vlsi design, and consequently can satisfy real time military processing needs

    本文通過對頻帶受限數字信號的離散傅立葉變換特性的研究，引進了交替投影神經網路，並將其應用范圍從實數域拓廣到復數域，且給出了在復數域仍然成立的若干結論.運用這些結論，在對網路噪聲抑制、網路收斂速度及待外推信號因截斷而造成頻譜嚴重外泄問題的分析與討論的基礎上，提出了一種基於交替投影神經網路的外推演算法.模擬實驗表明該方法是行之有效的.另外，該演算法對頻譜外推同樣適用；由於它採用全互連神經網路結構，易於并行計算和vlsi實現，從而可滿足軍事上實時處理的需要
  17. Because traditional radio monitoring system is composed of a spectrum analyzer and a single or a multi channel receiver, system performance and automation has been restricted greatly

    傳統的監測系統採用單通道或多通道數字監測接收機和頻譜分析儀構成，系統性能和自動化程度受到較大限制。
  18. Domestic free - to - air terrestrial broadcasters asia television limited ( atv ) and television broadcasts limited ( tvb ) warned the government against formulating digital terrestrial television ( dtt ) policies without knowledge of what technical standard the mainland would adopt and frequency plan coordination with mainland authorities had not been achieved

    本港兩家免費地面電視臺亞洲電視有限公司及電視廣播有限公司（無電視）向港府提出忠告，指在不清楚中國內地採用哪種技術標準前，以及尚未與內地機關完成頻譜規劃協調情況下，便制定數碼地面電視政策的做法甚不明智。
  19. The most important specification of the level measurement system is the accuracy. the range measurement accuracy of a fmcw radar is strongly affected by the stability and the linearity of the frequency modulation. thus the vco ' s nonlinearity correcting method is discussed

    利用fft （ dft ）頻譜估計頻率精度受fft頻率量化（即譜線之間的間隔）的限制，對應的fmcw雷達的距離估計精度則受掃頻帶寬的限定。
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