寬頻譜噪聲 的英文怎麼說

中文拼音 [kuānbīnpǔzàoshēng]
寬頻譜噪聲 英文
wide spectrum noise
  • 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）...
  • 噪 : 動詞1. （蟲或鳥叫） chirp 2. （大聲叫嚷） make noise; make an uproar; clamour
  • 頻譜 : frequency spectrum; frequency content; spectrum; power density spectrum; power spectrum; [系統] s...
  1. A large planar microphone array, which consists of 111 microphones, was successfully applied to obtain a two - dimensional mapping of the sound sources on a landing aircraft. the focus of study in this paper is on the landing gear noise source. the spectra, directivities and sound pressure levels of flap side - edge noise of 7 narrow - board commercial aircraft and 7 wide - board commercial aircraft are presented. it is found that the landing gear noise spectrum is broadband with some single tones in some cases. the directivity of the total sound pressure level of a landing gear noise resembles that of a horizontal dipole. the level differences between the various aircraft landing gears are larger than those expected from the airspeed differences. it is thus expected that the louder noise emission of the landing gears can be reduced by redesigning

    應用由111個傳聲器組成的平面傳聲器陣列對當前流行的民用客機進場著陸過程中的機體噪聲源進行了實驗測量，本文對七架窄體客機和七架寬體客機的起落架噪聲進行了分析，得到了起落架噪聲的頻譜特性、指向特性和聲級變化.研究發現，起落架噪聲的頻譜是由寬頻隨機噪聲與一些較為明顯的單音噪聲源組成，起落架噪聲的指向性類似於一個水平放置的偶極子.不同飛機起落架噪聲的聲級相差較大，這說明可以通過重新結構設計降低起落架噪聲。
  2. 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。
  3. The low - frequency discrete noise of the propeller is induced by the interaction between blades of the propeller and wake of the marine, and the low - frequency broadband noise of the propeller is produced by the interaction of blades and turbulent field of the marine stern

    螺旋槳的低頻離散譜噪聲是由船尾伴流場和葉片的相互作用引起的，而低頻寬帶噪聲是由船尾粘性湍流場和葉片的相互作用產生的。
  4. Abstract : a large planar microphone array, which consists of 111 microphones, was successfully applied to obtain a two - dimensional mapping of the sound sources on a landing aircraft. the focus of study in this paper is on the landing gear noise source. the spectra, directivities and sound pressure levels of flap side - edge noise of 7 narrow - board commercial aircraft and 7 wide - board commercial aircraft are presented. it is found that the landing gear noise spectrum is broadband with some single tones in some cases. the directivity of the total sound pressure level of a landing gear noise resembles that of a horizontal dipole. the level differences between the various aircraft landing gears are larger than those expected from the airspeed differences. it is thus expected that the louder noise emission of the landing gears can be reduced by redesigning

    文摘:應用由111個傳聲器組成的平面傳聲器陣列對當前流行的民用客機進場著陸過程中的機體噪聲源進行了實驗測量，本文對七架窄體客機和七架寬體客機的起落架噪聲進行了分析，得到了起落架噪聲的頻譜特性、指向特性和聲級變化.研究發現，起落架噪聲的頻譜是由寬頻隨機噪聲與一些較為明顯的單音噪聲源組成，起落架噪聲的指向性類似於一個水平放置的偶極子.不同飛機起落架噪聲的聲級相差較大，這說明可以通過重新結構設計降低起落架噪聲。
  5. At last we introduce the realization of all the parts, the problem in the circuit design and the measured data. the results show that the designed system has met the requirement. in this dissertation, direct digital synthesis technology has been used in the phase - locked frequency synthesizer, which can make full use of the characteristics of direct digital synthesis technology such as flexible output wave shape and continuous

    本課題將直接數字式合成技術用於鎖相頻率合成器中，該方法將直接數字合成的特點，如輸出波形靈活且相位連續、頻率穩定度高、輸出頻率解析度高、頻率轉換速度快、輸出相位噪聲低、集成度高、功耗低、體積小等與鎖相環路的頻帶寬、工作頻率高、頻譜質量好等優點有機的結合起來，從而在寬帶的條件下實現了比較好的雜散性能和相噪。
  6. Abstract : to against the fact of the commercial available white noise generators are very expensive which is not good for general operations, a simple and effective limited band white noise generator is design. the generator is using the feature of dual polarity transistor, i. e., the power spectrurn density of particulate noise is not related to frequency in very wide band and close to white noise. the concrete circuit is also given

    文摘:針對市售白噪聲發生器價格昂貴，不利於一般場合使用的問題，介紹利用雙極性晶體管散粒噪聲功率譜密度在非常寬的范圍內與頻率無關，屬白噪聲這一特性，設計了一種簡捷、有效的限帶白噪聲發生器，並給出了具體電路。
  7. Chaotic signal with continuous wide band frequency spectrum is not periodic and is similar with noise signal. these properties make it suitable to secret communication

    由於混飩信號的非周期，連續寬帶頻譜，似噪聲等特點，特別適用於保密通信領域。
  8. But they have the disadvantages such as poor complexity, poor security and insufficient amount of sequence numbers among the family of codes, the chaotic signals have noise ? ike, broadband frequency spectrum, they can be used as spreading codes, furthermore, chaos system is extremely sensitive on initial conditions so that the various initial conditions given by chaos system can provide with large sum of spreading sequences and this can meet the demand of cdma, this thesis sets out to study on using chaos system to generate spreading sequence s, there are two parts is this paper : firstly, we study the basic theory of spread ? pectrum communication and the characteristics of chaos so as to prove the applicability of chaos system to be used in spread ? pectrum ii communication system

    現在使用的擴頻碼有m序列， gold碼和r - s碼等，這些擴頻碼具有良好的隨機性，但普遍存在著復雜度低、保密性差以及同一碼族序列數目少等缺點。混沌信號具有類似噪聲、寬帶連續頻譜的特徵，正符合擴頻通信中對擴頻碼的要求，而且混沌系統對初始值極其敏感，可以通過給混沌系統賦予不同的初始值得到為數眾多、不相關的擴頻序列，這正好滿足碼分多址的要求。本文對利用混沌系統應用於擴頻通信作了一些研究工作，主要包括兩部分：第一部分：探討了擴頻通信的基本理論和混沌的基本特性，說明將混沌系統應用於擴頻通信系統的可行性。
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