調制頻譜 的英文怎麼說

中文拼音 [diàozhìbīnpǔ]
調制頻譜 英文
modulation spectrum
  • 調 : Ⅰ動詞1 （配合得均勻合適） harmonize; suit well; fit in perfectly 2 （使配合得均勻合適） mix; adju...
  • 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 : 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）...
  • 頻譜 : frequency spectrum; frequency content; spectrum; power density spectrum; power spectrum; [系統] s...
  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. Supervisor point is behind the postposition of power amplifier, optic signals coming from a tap of 99 : 1 enter into optic spectrum scan module, then the power levels which have been calculated by iterative algorithmic are sent to power control module to guide a set of tunable electronic attenuators

    此方案將監測點放在後置功率放大器的後面，從分束器中分出99 ： 1的光進入光頻譜掃描模塊，傳給功率控制模塊的光功率值經過選代演算法后計算出均衡后的功率值送到功率控制模塊的控制中心去調節電可調節衰減器。
  3. 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。
  4. In recent years, the worldwide researchers pay much attention to fourier telescopy. it is an active imaging technique that encodes the information in the temporal instead of spatial domain, then receives the speckle and deposed of it to reconstruction the object image. now, the high - resolution technique is under the condition of deeply researched

    它是一種主動式干涉成像技術，這一技術通過時域內的相位的調制完成直線條紋對目標的掃描，從而達到對深空目標頻譜的抽樣，然後接收其散射回波，對回波信號進行處理，進而還原出目標的像。
  5. Is responsible for regulating the telecommunications industry in hong kong. its responsibilities include economic regulation, technical regulation, enforcing fair competition rules, setting technical standards, co - ordinating the development of the telecommunications infrastructure, investigating consumers and industry complaints, managing the radio spectrum, providing advice to the government on telecommunications matters and representing hong kong in international telecommunications organisations

    負責監管香港的電訊業，其范圍包括經濟規管，技術規管，執行公平競爭條款，制訂技術標準，協調電訊基礎建設的發展，調查消費者和業界的投訴，管理無線電頻譜，就電訊事宜向政府提供意見，以及代表香港參與國際電訊組織。
  6. 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。
  7. Secondly, the paper researches blind estimation of signals parameters, including the carrier frequency, signal to noise ratio and symbol rate of digital modulations. thirdly, with the combination of parameters from early studies on the decision theory, a set of robust feature parameters are extracted from signal power spectrum and the power spectrum of the second and fourth power of signal. based on these parameters, the proposed scheme is able to recognize 12 types of common used modulations, namely ask 、 2fsk 、 msk 、 4fsk 、 psk 、 qpsk 、 / 4qpsk 、 8psk 、 am 、 dsb 、 ssb 、 fm

    接著，對信號功率譜、平方譜及四次方譜進行研究，針對通信中常用的調制方式，結合前人提出的基於決策理論中的特徵參數，設計了一組對信噪比和信號調制參數不敏感的分類特徵參數，利用上述參數完成了一種基於信號頻域的識別方法，可以對ask 、 2fsk 、 msk 、 4fsk 、 psk 、 qpsk 、 / 4qpsk 、 8psk 、 am 、 dsb 、 ssb和fm這12種常用調制方式進行識別。
  8. 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。
  9. A cyclic radial shearing interferometer was used to diagnose the wavefront distortion of a laser system and an lcslm ( liquid crysnd spatial ligh modulator ) was used to control it. some results have been summarized as follows : l. according to the theory of scalar quanity diffeaction and the model of the random gaussian phase screen of low frequency wavefront, the effect of the low frequency wavefront with different rms gradient on the focal spot of a laser beam was studied

    本論文在激光光束波前畸變檢測和控制上進行了新的探索，主要就空間相位調制環路徑向剪切干涉儀以及它對波前畸變的檢測和液晶空間光調制器及其對中頻段波前畸變的控制進行了研究，其研究的內容和取得的成果如下：一、根據標量衍射理論，結合低頻波前畸變的高斯隨機位相分佈模型，研究了不同均方根梯度低頻畸變波前對激光光束焦斑聚焦性的影響，並採用描述中頻段波前畸變的功率譜密度概念，模擬計算了它對激光焦斑旁瓣的貢獻。
  10. Frequency spectrum according to pulse partition modulation signal

    基於脈沖間隔調制信號的頻譜
  11. This article analyses the signal characteristics of several typical cw radars, and presents the principle and application of doppler radar. as one focal point, this article researches the generation and math characteristics of pseudorandom code modulated signal, analyses the spectrum of pseudorandom code phase modulation radar signal, and presents this kind of signal ' s application in distance and speed measurement. this article also researches the application of mono - pulse amplitude comparison radar in angle measurement finally, this article elaborates the working process of crs in uast

    本文分析了幾種典型的連續波雷達信號的特性，介紹了多普勒雷達的原理和應用；研究了偽隨機編碼信號的產生和數學特徵，著重分析了偽碼調相連續波雷達信號的頻譜，及其在雷達測距、測速方面的應用；研究了單脈沖幅度比較體制在雷達測角中的應用；最後，闡述了超近反導系統中復合體制雷達的工作過程。
  12. Along with the development of the technology of the wireless communication particular the modern modulation and software radio technique, meantime the employ of wireless frequency are more presser, the development of the receiver tend towards high performance and high integration

    隨著無線通信技術特別是現代調制體制和軟體無線電技術的快速發展，且無線頻譜的擁擠程度日益加劇，無線電接收機在設計和實現上越來越趨向于高性能、高集成度方向。
  13. 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。
  14. A comprehensive theory is presented for fm spectroscopy of doppler - broadened molecular iodine absorption lines. the relationship betwcen fm spectroscopy and modulation frequency and modulation index has been studied. the whole circuit for thc frcquency stabilized laser system has been developed

    建立了多普勒加寬碘分子線性吸收fm光譜的一般理論，對fm光譜與調制頻率和調制度的關系進行了研究；並研製了532nmnd : yvo _ 4 / ktp碘吸收穩頻激光器的電路系統；提出了虛擬激光穩頻技術的概念。
  15. Qpsk modulation for digital television using advanced digital signal processing technology, full compliance with dvb - s standard, the receiving end can be directly used for receiving digital satellite receiver. it must not only be able to achieve a higher utilization of the spectrum, with a strong anti - jamming and high performance. fm microwave equipment and simulation and will be good compatibility

    Qpsk數字電視調制器採用了先進的數字信號處理技術，完全符合dvb - s標準，接收端可直接用數字衛星接收機進行接收。它不但能取得較高的頻譜利用率，具有很強的抗干擾性和較高的性能價格比，而且和模擬fm微波設備也能很好的兼容。
  16. 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。
  17. 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。
  18. Simulations on light intensity are validated by experiments and influence of mechanical dither on gyro frequency stabilization is studied for the first time. then it is point out that the key to improve the precision of frequency stabilization is to choose appropriate modulation frequency based on the frequency spectrum of sharp pulses, which is introduced by mechanical dither. thereafter, experiments of frequency stabilization under different modulation frequencies are made

    通過實驗驗證了光強模擬結果，首次分析了機械抖動對穩頻的影響，指出提高機抖陀螺小抖動穩頻精度的關鍵在於：根據機械抖動引入的交流光強尖峰脈沖頻譜分佈選擇合適的調制頻率，並給出了不同調制頻率的穩頻實驗結果。
  19. Secondly, considering the need of frequency stabilization, mdrlg ' s light intensity is simulated. the simulations indicate that sharp pulses are produced in the ac light intensity by mechanical dither. as the pulses have a wide frequency spectrum and range over the modulation frequencies of frequency stabilization, mechanical dither may reduce the precision of frequency stabilization

    其次，根據穩頻需要對機抖陀螺輸出光強進行了模擬，模擬表明機械抖動會在交流光強中引入尖峰脈沖，且尖峰脈沖頻譜分佈較寬，在小抖動穩頻調制頻率范圍內有功率輸出，因而可能降低穩頻精度。
  20. Direct measurement of ch4 absorption spectrometer by means of tunable frequency modulated diode laser

    激光頻率調制光譜法測量甲烷的吸收光譜
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