頻率下變換器 的英文怎麼說

中文拼音 [bīnlǜxiàbiànhuànqì]
頻率下變換器 英文
frequency down convertor
  • 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...
  • 率 : 率名詞（比值） rate; ratio; proportion
  • 下 : 下動詞1. （用在動詞后,表示由高處到低處） 2. （用在動詞后, 表示有空間, 能容納） 3. （用在動詞后, 表示動作的完成或結果）
  • 換 : 動詞1. （給人東西同時從他那裡取得別的東西） exchange; barter; trade 2. （變換; 更換） change 3. （兌換） exchange; cash
  • 器 : 名詞1. （器具） implement; utensil; ware 2. （器官） organ 3. （度量; 才能） capacity; talent 4. （姓氏） a surname
  • 頻率 : frequency; rate
  1. We also researched the frequency structure of ddc and interchanged the filter multiphase heft and taking out - operation using the theory of equivalent counterchange in multisampling system

    從理論上研究了數字下變頻的頻譜結構，利用多采樣率系統中結構的等效變換原理，將濾波器多相分量與抽取操作進行互換。
  2. The specific research methods are listed : 1. matched filter taking the max ouput snr as the best rule correlates nonstop divided signal and divided echo to detect low snr target signal. then all one dimension divided correlation outs and done fft in portrait to leach interferential signal such as static or low rate mussy meaves, many pathway echo and so on and to take target ' s time difference and doppler frequency that combine parameters that target ' s direction taken from antenna and so on to implement target ' s orientation and tracking

    具體研究方法如下： 1 、採用以輸出信噪比最大為準則的最佳匹配濾波器來對分段的參考和目標信號作相關處理來檢測低信噪比目標信號，然後對一維分段相關輸出組作縱向傅立葉變換來濾除靜態或低速的雜波、多徑回波等干擾信號，並提取目標的時差和多普勒頻率，再結合由天線獲得的目標方向等參數，就可以實現目標的定位和跟蹤。
  3. To utilize the advantages of dsp chips, the system should be computing sources economical. according to digital signal processing theory, the poly - phase fir can help reduce the workloads of the ddc / duc. therefore, adding the complex carrier mixers, the channelization system ( a method of using a single wideband facility to transmit many relatively narrow - bandwidth signals. by subdividing the frequency spectrum used in the wideband channel ) can be formed utilizing the characters of fft

    為了使開發出的軟體可以適用於高速dsp器件開發，節省系統資源，課題首先從數字信號處理的理論進行分析，得出可以利用抽樣率轉換的數字濾波器的特點，即多相濾波實現數字上下變頻計算負擔的減小，之後進一步將多相濾波器與頻譜搬移部分結合，通過公式的推導，得出可利用快速傅立葉變換的特點實現多路信號的通道化發射和接收的處理模型。
  4. The temperature range is - 30 ~ 80. the topology of the step - up dc / dc converters and its basic principle is first analyzed in this thesis. then based on the conventional pfm control scheme, a discrete pulse frequency modulation is presented and the state space average model related to the ccm ( continue current mode ) and dcm is established

    然後在傳統的脈沖頻率調制方式的基礎上，分析了一種離散脈沖頻率調制方式，並建立了這種調制方式下升壓型dc / dc變換器在電流連續（ ccm ）工作模式和電流斷續（ dcm ）工作模式的狀態空間平均模型。
  5. High - frequency link power converters are receiving increasing attention. when the input frequency of ac - ac converter is quite high, such as 20khz or above, in order to make sure the converter switching action is restricted to the zero crossing point of the link voltage, the switching cycle becomes discrete pulse spectrums, however, the conventional pwm converters are ruled out because they would fail either to the efficiency or the low - distortion criteria

    當交-交變頻器的輸入頻率非常高，通常為20khz時，為了在零電壓條件下實現逆變器開關管的通斷，變換器的開關時刻必須選擇在高頻交流電壓脈沖為零時，這意味著變換器開關時刻在時間軸上成為不連續的點，而常規的硬開關pwm變換器是將開關時刻選擇在任意時刻。
  6. Through analysising the characteristics of the power system with floating neutral point deeply, the paper puts forward a new plan of single - phase to ground fault line selection on the base of s ' s signal injecton method and gives the hardware and software design. in this design, the high speed sampling and data processing is carried out through using dsp processor ; the large electrice current is drived through the application of a high - performance audio power amplifier and transformer ; the communication between host computer and detectors is realized through rs485 bus technology ; the difference multilevel frequency - selected amplifier is designed and the feeble signal of space is sampled on the base of the theory of magnetic induction ; the interface between dsp and exterior chip and rs485 interface logical is designed through using fpga ; the using of lcd module and keyboard interfacing chip makes the interface between human and machine ; the programme of host computer and detectors is designed through using blocking design method

    在本設計中，採用高速的dsp處理器，實現了對故障特徵信息的高速採集與處理;採用大功率的功放晶元與變壓器配合的方法，實現了大電流信號的驅動輸出;採用485總線技術，組建了裝置主機與多探測器之間的主從式通訊網路，實現了多干擾條件下裝置主機與多探測器的可靠通訊;設計了差分式多級選頻放大電路，採用磁感應的方法實現了對空間微弱信號的接收;利用fpga技術，實現了控制器與多外設的介面及數字信號的串並轉換;採用了先進的lcd液晶顯示模塊及鍵盤介面晶元，設計了人機信息交互的介面;採用了模塊化的軟體設計方法，開發了裝置主機及探測器的軟體程序。
  7. Conventional hard switching technology has several flaws below : on and off loss, inductive off, capacitive on and diode recover problems. comparing with it, the loss of on and off decreases markedly, as the switches are on and off in zero voltage or zero current cases. and also the size of converter becomes smaller because of the higher of switching frequency

    傳統硬開關技術由於存在開通關斷損耗大、感性關斷、容性開通、二極體反向恢復等問題，與之相比，軟開關技術在零電壓或零電流條件下導通，開關損耗明顯降低，加上開關頻率的提高使得變換器的體積得以減小，這也是軟開關技術受到青睞的原因。
  8. The main works are as follows : 1. the paper systematically describes basic concepts and theories that form the foundation for design of general microwave filters. the topics will cover filter transfer function, lowpass prototype filters, frequency transformations, immittance inverters and the passband insertion loss under the influence of the dissipation of filter elements 2

    現總結如下: 1 .對微波濾波器的設計理論進行系統的分析，闡述了微波濾波器的傳輸函數、低通原型、頻率變換、倒置變換器以及元件損耗對帶內插損的影響等方面。
  9. A x - band six - cavity tro is studied. with the voltage 760kv 6ka and the magnetic field 2. 6t in the simulation, output power is about 1. 5gw is obtained, and interaction efficiency is 31 %. a noveland high accurate numerical synthetic technique is presented for determining the high frequency characteristics of six - cavity with open boundary

    對粒子模擬的輸出微波功率的作出診斷，找到讀取微波功率快速有效的方法：在電場和磁場同相的前提條件下，對時域波形進行傅立葉變換，微波功率頻域的二倍頻所對應的幅度即為微波x波段渡越輻射振蕩器的理論和實驗研究平均功率的大小。
  10. This paper include the following parts. firstly the sine exciting - voltage is guaranteed by direct digital synthesize technology ; secondly the digital output of cos ( 9 ) and sin ( 9 ) are generated by microcontroller ; thirdly the two voltage signals which are the product of the two former signals gained by the multiplying d / a converter, being filtered and amplified, have constant frequency, and one amplitude has sine function relationship of with the input angle, and the other amplitude has cosine function relationship of with the input angle ; finally the two signals are acquired and analyzed by relative instrument and software

    主要由以下幾部分組成：用數字頻率合成技術（ dds ）產生正弦激勵電壓信號u _ msin （ t ） ；用單片機產生幅度的數字量輸出sin （ ）和cos （ ） ；用乘法型d a轉換器實現激勵電壓和幅度的乘積，並通過濾波器和功放后即得到頻率固定，幅值隨輸入角成正餘弦變化的電壓信號；最後用數據採集卡採集輸出信號，顯示波形並進行頻譜分析。
  11. In this part, the high - frequency series inverter with resonant pole capacitor is introduced mainly. the current - exchanging processes of the inverter in different working modes are analyzed, how to reduce the switching loss is discussed, and the calculating methods of snubber capacitor c, factor angle switching frequency and pulse width pw are given in optimum switching process. and results of simulation and experiment verify the validity of theoretic analysis

    接著重點研究了含有諧振極無損緩沖電容的逆變器，對其換流過程中的不同工作狀態進行分析，討論了如何減小逆變器的開關損耗，給出了最佳工作狀態下緩沖電容c 、感性角、開關頻率、觸發脈沖的脈寬pw的詳細計算方法，並通過大量的模擬和實驗波形證明了理論分析的正確性。
  12. It has been found that by simulating the effect of coupling attenuation on all - optical wavelength conversion, all - optical wavelength conversion by using both light conversion and idle light can be realized respectively by adjusting coupling attenuation under the condition of different pump light and signal light powers

    文章通過模擬耦合器衰減對全光波長變換的影響，發現在不同的泵浦光與信號光功率條件下，調節輻合器衰減可分別實現利用變換光的全光波長變換和利用閑頻光的全光波長變換。
  13. But the switching loss is increased as the switching frequency is improved and so the converter efficiency is decreased

    但隨著開關頻率的提高，硬開關的開關損耗增加，變換器的工作效率隨之下降。
  14. Further, the characteristics such as the response speed, the efficiency and the relationship between load and the modulation factor are counted and analyzed. during the stage of circuit design, the whole chip and the sub - block circuits are well - designed, respectively

    基於此模型，計算並分析了離散脈沖頻率調制下升壓型dc / dc變換器的響應速度、效率和負載與調制度的關系等特性。
  15. First, variable speed constant frequency wind energy convertion theory is described in this paper, then presents a review on the development of wind turbines control and the main types of generator and static converters used to interface variable speed wind turbines to the electric grid. then discuss main circuit constructure and advantage of direct drive wind energy conversion system and introduce pitch - control method for wind power traction and electric power stability. simply aerodynamic characteristic of the turbine is analysised and permanent magnet synchnonous generator math model is established. to convert the variable frequency electricity into utility grid, back to back four - quadrant pwm - vsi is used and three typies of control strategy is presented to capture the maximum wind energy and transmit energy. then simulation is implemented to test the control strategy. in the following chapter a simple ac - dc - ac converter with a dc - dc boosting chopper is proposed to transmit the wind energy into electricity energy and two control strategy is presented

    建立了永磁電機和變流器的數學模型，針對雙pwm變頻器的特點提出了三種控制策略對變流器進行控制，通過變流器交-直-交的變換，將發電機發出的變頻變幅值交流電轉化為可用的恆定頻率的交流電，通過pwm調治能使其輸出功率因數為一，並且該控制系統功率因數為可調，能在特殊情況下同電網交換一定的無功功率，並通過對變流器的控制實現了最大風能俘獲的功能。最後採用matlab / simulink進行了模擬，取得了良好的模擬效果。在風力發電系統中，採用先進的最大功率俘獲演算法，能有效的從風中獲得最大的能量。
  16. 1. nizn ferrite was developed for using in mini high frequency dc - dc converters and inductors. we measured and analysed the parameters of the nizn ferrite, which we concern about when designing the dc - dc converter. 2. the low loss sample of nizn ferrite were chosen for design - optimization of the high frequency transformer. based on the relevant theoretical researches, the loss properties of the magnetic core material and winding were analyzed in this thesis

    因此，以nizn功率鐵氧體材料為開關電源芯材為基礎，並優化各種開關電源的設計已成為國際上的熱點和技術瓶頸，本論文正是以上述背景為研究目標而開展工作的，主要進行的工作和創新有: 1 .對研製的新型高頻低功耗的功率nizn材料進行參數的測試，並針對dc - dc變換器設計關心的參數對芯材特性進行了分析，選擇在特定頻率下，功耗較小的nizn材料磁芯樣品作為變壓器優化設計的預備磁芯。
  17. By use of gabor wavelet transform and mae technologies, the arrived time to sensors of transient ae signals of specific guided mode can be precisely obtained. as the result, the precision of leak location was improved

    利用gabor小波變換方法對斷鉛聲發射信號進行時頻分析，通過確定某一頻率下某一模態導波到達傳感器的時間，較好地實現了聲發射源定位。
  18. The mathematical and circuit analyses of the converter show that the output current of the dc - dc converter tends to be saturated with the gradually increasing product of the operation frequency and the capacitor capacitance in the case of a determinate effective loop resistance

    分別用matlab和pspice從理論和電路兩個方面進行的模擬研究都表明：在等效同路電阻一定的情況下， dc - dc變換器的輸出電流隨工作頻率和電容容量乘積的增大而趨于飽和。
  19. Presents the simple but highly reliable on - line detection of ultrasonic transducer clamping capacitance based on the impedance circuit model constructed through the impedance characteristics of the ultrasonic transducer under triple harmonics, and concludes from experimental results that this method can be used to effectively detect the variation of clamping capacitance while the transducer is operating, and the matching inductance can be dynamically regulated according to the results of detection, and dynamic matching can therefore be achieved in the real sense at the end of the transducer to improve the overall performance of the whole system

    為了解決大功率超聲應用的換能器電端匹配問題，分析了超聲波換能器在諧振頻率三次諧波下的阻抗特性，給出了超聲換能器三次諧波下的阻抗電路模型.並根據阻抗電路模型建立了對超聲換能器的夾持電容實現在線檢測簡單、可靠性高的方法，實驗證明該方法有效的.該方法可以在換能器工作過程中隨時檢測夾持電容的變化，根據檢測結果對匹配電感進行動態調整，實現真正意義上的換能器電端的動態匹配，從而大大改善匹配質量，提高系統的工作性能
  20. However input current distortion at the zero - crossing of the input voltage is a common problem in active pfc converters, and it becomes more serious as the line frequency is increased. the purpose of this thesis is to reduce the zero - crossing distortion of input current at high input frequency application

    但有源pfc變換器存在輸入電流過零畸變的缺陷，並且隨著輸入頻率的升高而越來越嚴重，本文的工作就是針對解決高輸入頻率下嚴重的輸入電流過零畸變而展開的。
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