載波的頻譜 的英文怎麼說

中文拼音 [zǎibōdebīnpǔ]
載波的頻譜 英文
spectrum of carrier
  • 載 : 載Ⅰ名詞（年） year : 一年半載 six to twelve months; six months to a year; 三年五載 three to five ...
  • 波 : Ⅰ名詞1 （波浪） wave 2 [物理學] （振動傳播的過程） wave 3 （意外變化） an unexpected turn of even...
  • 的 : 4次方是 The fourth power of 2 is direction
  • 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）...
  • 載波 : signal carrier; carrier wave; carrier: 3路載波 three channel carrier載波傳輸 carrier transmission...
  • 頻譜 : frequency spectrum; frequency content; spectrum; power density spectrum; power spectrum; [系統] s...
  1. However, the efficiency of pwm at light load is low and the filter design of pfm is rather difficult due to the random characteristic of the frequency spectrum distribution

    採用相應調制方式的ic品種繁多，各有千秋。但pwm在輕載時效率較低，而pfm由於頻譜分佈隨機，不利於后續濾波器的設計。
  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. 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。
  4. In wavelength conversion based on four - wave mixing ( fwm ) in soa, balance efficiency can be obtained in larger range when increasing saturation power of the optical amplifier and decreasing the saturation power of spectral hole burning and carrier heating

    而在基於soa的四波混頻（ fwm ）波長轉換中，在提高光放大器飽和功率的同時減小光譜燒孔（ shb ）和載流子加熱（ ch ）飽和功率可有效提高較大頻率間隔處的轉換效率，並保持其在較大頻率失諧范圍內的效率均衡。
  5. The characteristics of the ground clutter are analyzed and presented. the development and the theories of clutter suppression of airborne radar are desicribed systematically

    首先分析總結了地物雜波頻譜的組成特性，系統地闡述了機載雷達雜波抑制的基本理論及其發展動態。
  6. This paper mainly focuses on the noise limiting by means of the direct sequence spread spectrum ( dsss ) and the analysis of the transmission performance of the plc and some digital modulation technology. the contents of the paper is as follows : 1 ) the technical feasibility is proved after simulating noise limiting principle of dsss by means of systemview, the simulation software ; 2 ) a kind of band pass filter ( bpf ) is realized according to the requirement of filter and the principle of butterworth approximation, which satisfies the index of performance of dsss. 3 ) the low voltage plc system includes the sc1128, the specific modulation / demodulation ic, the bpf filter and other circuit components, furthermore, the control function of system is realized by means of the personal computer and the microcontroller

    本課題在對低壓電力線的傳輸特性和數字調制技術進行分析的基礎上，將通信理論中的直接序列擴頻技術（ dsss ）用於解決低壓電力線通信的干擾問題，主要研究內容如下： （ 1 ）用通信模擬軟體systemview對dsss技術的通信和抗干擾原理進行模擬分析，分別對時域和頻域下採用dsss技術前後接收信號的頻譜進行分析，驗證dsss技術在本系統中的可行性； （ 2 ）由dsss技術對濾波系統的要求，根據濾波理論分析了巴特沃思型濾波器的逼近原理並設計了合適的濾波電路； （ 3 ）用調制解調晶元sc1128和自行設計的濾波器加之輔助外圍電路，構造出低壓電力線載波通信系統，並採用atmel公司的單片機設計了接收和發射電路的微控制器； （ 4 ）分別對採取抗干擾措施前後輸入和輸出信號進行對比實驗，並對結果進行分析，驗證了dsss技術對干擾信號的抑制作用。
  7. An improved ar model spectral estimation for carrier frequency. 3

    提出了用改進的ar模型譜估計方法估計載波頻率。
  8. This article describes a way of special ultrasonic system which monitors thermal stress in seamless welded rails. this monitoring system is a non destructive testing system, which adopts avr mcu and high - precise time chip processing as the core of it, and adopts the critically refracted longitudinal wave as the object of measuring. my studying focuses on the theory of the monitoring system, which will be listed in this arctile : according to the snell theory, the theory of motivating of critically refracted longitudinal wave is described in details, and the finite element software is used to emulate the propagating course. the formulas of calculating the pts of swr are taken from the acoustoelasticity theory, and the calculating the parameters is introduced. according to assemble materials, three kinds of ways of monitoring the pts of swr using critically refracted longitudinal wave are described, which are measuring the sound - time in changeless distance, ultrasonic critical - angle refractomery and frequency spectrum, the first way of ways is used in this experiment system. the factors, which effect the monitoring system, are assaid in some degree based

    本文的研究工作重點在無縫焊接鋼軌溫度應力測量系統的理論模塊，包括根據snell原理，研究極限折射縱波的激發機理，並使用有限元軟體ansys進行模擬;根據聲彈性理論以及公式推導出計算無縫焊接鋼軌中的溫度應力的公式，並對其中參數的求解方法進行介紹;根據收集的資料，介紹了三種使用極限折射縱波測量無縫焊接鋼軌溫度應力的方法，即固定距離測量聲時法、臨界角折射法和頻譜分析法，本實驗系統使用的是第一種;根據實驗經驗以及相關資料，分析了影響極限折射縱波測量溫度應力的幾個因素，並提出了相應的解決方法;根據實驗系統的需要，獨立設計並加工出相關配套的實驗設備，包括實驗鋼塊、有機玻璃楔塊、固定件、載荷外框裝置等。
  9. Then one remote supervision system based on virtual instrument technology is studied and realized. the system can measure parameters such as signal level, carrier frequency and snr of remote channel, and can estimate the state of remote channel based on this parameters, and can display the time - domain and frequency - domain wave real time of remote channel, too

    針對目前遠動監控方案的不足，研究並實現了基於虛擬儀器技術的電力遠動通道監控系統，該系統可以對遠動收發信電平、載波頻率和信噪比三個通道參數進行測量，具有實時時域波形和功率譜波形顯示功能，並能根據通道參數對通道狀態進行綜合判斷。
  10. In chapter 3, this paper recommended the methods of estimating the parameter of moving target using cyclostationary and analyzed the performance of this method firstly, and put forward a recursive method for estimating the parameter ( velocity, acceleration ) of moving target combining the characteristic of high - prf pulsed doppler radar. then, based on the resolution of doppler and acceleration, combining the characteristic of the doppler spectrun and acceleration spectrum, this paper put forward a new method for differentiating muli - target

    然後，從彈載高重頻脈沖多普勒雷達的多普勒解析度和加速度解析度出發，結合不同編隊方式的多目標回波信號的特點，分析了多目標和單個目標的回波信號的多普勒譜和加速度譜的特性，提出了一種基於一維多普勒像和一維加速度像的級次多目標分辨演算法。
  11. This article takes hanging off and wide fluctuation of transmition velocity of adsl as example, then analysis centers on the discerte multiple tone and the principle of channel load assignation. from analysis above article points out the root of adsl being sensible of noise signal. at last, reserches effects that window function and barrier effect on frequency and adopts fft to work out the noise power of adsl

    本文以電信現在推出的adsl傳輸中鏈路經常掉線和傳輸速率經常大范圍波動為例，重點分析了adsl所使用的dmt調制方式和注水演算法分配通道載荷方式原理，由此指出adsl對噪聲信號敏感的根源，在得到問題的根源之後，分析了窗函數和柵欄效應對頻譜的影響，採用fft方法計算adsl線路的噪聲功率譜，為adsl線路測試提供了可靠的理論依據。
  12. The work of this dissertation is focused on research of some key technics in signal design and processing of mcpc signal. the main content of the dissertation is summarized as follows : it gives a detailed description of the form of the mcpc waveform and its mathematical model, and analyses the formation and properties of phase coded sequence. it discusses the effect of signal parameters on autocorrelation, power spectra and ambiguity function in forms of single pulse and pulse train and compares different kinds of single pulse signals and pulse train signals

    本文圍繞著多載波相位編碼信號在信號設計與信號處理的若干關鍵問題進行了研究，主要做了以下工作:描述了多載波相位編碼信號（ multicarrierphasecoded ，簡稱mcpc ）的信號形式，給出了其數學模型，對其中相位編碼序列的構成方式與特性進行了分析;從單脈沖和脈沖串兩種信號形式入手，對多載頻相位編碼信號的參數在自相關函數、功率譜密度和模糊方程上的影響作了詳細地討論，對不同調制方式的單脈沖和脈沖串信號進行了比較。
  13. Ds signal is twice modulated with the rapid pseudorandom noise sequence and the carrier. so it appears cyclostationary. in the field of spectral correlation, ds signals appears its characteristic as fallows : for the amplitude of spectral correlation, the information of carrier frequency and pn code rate are contained on the spectrum frequency equal to zero sheet, and also the pn code rate is contained on the sheet of spectrum frequency equal to carrier frequency ; for the phase of spectral correlation, the information of carrier initial phase is contained on the sheet of cyclic frequency equal to double carrier frequency

    Ds信號是經過高速偽隨機序列和正弦載波二次調制的寬帶信號，因此具有周期平穩特性，它在譜相關域表現為:幅頻特性在譜頻率等於零截面切片上包含了載頻和偽碼速率信息特徵，在譜頻率等於載頻截面切片上包含了偽碼速率信息特徵;相頻特性在循環頻率等於兩倍載頻截面切片上包含了載波初相信息特徵。
  14. Electromagnetic compatibility and radio spectrum matters - electromagnetic compatibility standard for radio equipment and services - part 26 : specific conditions for imt - 2000 cdma multi - carrier base stations and ancillary equipment v2. 2. 1

    電磁兼容性和無線電頻譜情況.無線電設備和服務的電磁兼容性標準.第26部分: imt - 2000 cdma多載波基站和輔助設備的具體條件
  15. To overcome the affection of ici and awgn on the ls estimate of the transfer function at pilot tones, the proposed bispectrum - based channel estimation algorithm employ the suppression of ici and awgn components in the received pilot signals by bispectrum and then the accuracy of the estimation is improved. with the channel estimation at pilot tones, an efficient interpolation is necessary. an improved interpolation method based on transform - domain filtering is proposed, which employs dft / idft and filtering in a transform domain so that the effect of noise on the equalization is significantly reduced

    針對導頻處通道傳遞函數的ls估計中存在載波間干擾和加性高斯白噪聲的影響的這一問題，本文將傳統的ls估計方法與雙譜相結合提出了一種新型的基於導頻雙譜通道估計演算法，它利用了雙譜對高斯噪聲的抑制作用來減小接收到的導頻信號中的載波間干擾和加性高斯白噪聲的影響，從而提高了導頻子載波上通道估計的精度。
  16. According to the carrier wave leakage and mirror wave interference in the signal generation, this paper analyzes the source of waveform distortion and its influence to signal spectrum and pulse compression result

    針對生成信號中存在的載漏和鏡像等失真，本文對波形失真來源及其對信號頻譜及脈壓結果的影響進行了全面分析與模擬。
  17. Then time domain synchronization including symbol, frequency and carrier synchronization algorithms is discussed according to the characteristics of frame structure in merged scheme. at the same time, pointed out its merit that high rate of spectrum utilized and rapid synchronization retrieved. and simulation and much improvement are done to realize the algorithms in project

    然後根據融合方案的幀結構的特點，分析和探討了時域同步演算法，包括符號同步、載波頻率同步和采樣同步演算法原理，指出時域同步有頻譜利用率高，同步恢復快等優點，並對其進行了工程可實現的改進和模擬。
  18. Ofdm is one of multi - carrier digital modulation techniques, in which a single high data rate data stream is transmitted using a number of lower data rate sub carriers, it has many properties, such as robustness to multi - path fading, high data rate transmission capability with high bandwidth efficiency, and so on

    Ofdm是一種特殊的多載波傳輸方式，它使用一系列低速子載波并行傳輸數據，使得它具有抗多徑干擾的能力、能以很高的頻譜利用率實現高速數據傳輸等。
  19. Multicarrier wireless communications have been widely investigated in the past decades. recently, two - dimensional spread spectrum ( 2d - ss ) system has drawn a lot of attention because of its full utilization of spreading characteristics in the frequency domain and time domain. compared with multicarrier code division multiplex access ( mc - cdma ), 2d - ss system can effectively mitigate multiple access interference ( mai ) due to spreading in the time domain

    當前多載波無線通信技術得到了廣泛的研究，二維擴頻通信系統是近年來提出的新的擴頻通信方式，由於二維擴頻系統從時域和頻域上分別對數據信號進行頻譜擴展，因此它同時具有時域擴頻和頻率擴頻通信系統的特點，是對傳統的一維時域直接序列擴頻和多載波擴頻的推廣。
  20. Firstly, in wireless environment, receiver has no know the time delay between transmitter and itself. in ofdm system, ofdm data is transmitted as one symbol, so in order for correct demodulation, the correct start of symbol should be got from ofdm system to reduce the effect of isi. secondly, the high frequency utilization in ofdm is based on the orthogonal properties of sub carriers. if frequency offset is generated, the orthogonal properties among sub carriers will lost, that will cause inter carrier interference ( ici ) and high ber of system

    Ofdm技術也存在著一些缺陷，首先，在無線環境中傳輸的ofdm信號對定時要求高，為了減少碼間串擾（ isi ）影響，必須從接收信號中提取出正確的符號起始位;其次， ofdm系統對頻率偏移敏感， ofdm技術的高頻譜利用率和傳輸可靠性均以子載波的正交性為基礎，如果接收機和發射機之間發生頻率偏移，子載波之間就會失去正交性，導致嚴重的子載波間干擾（ ici ） ，降低系統性能。
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