頻率換算系數 的英文怎麼說
中文拼音 [bīnlǜhuànsuànxìshǔ]
頻率換算系數
英文
frequency scale factor- 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
- 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
- 算 : Ⅰ動詞1 (計算數目) calculate; reckon; compute; figure 2 (計算進去) include; count 3 (謀劃;計...
- 系 : 系動詞(打結; 扣) tie; fasten; do up; button up
- 數 : 數副詞(屢次) frequently; repeatedly
- 頻率 : frequency; rate
- 換算 : [數學] matrixing; scaler; conversion; convert; translation換算表 conversion table; equivalent tab...
- 系數 : [數學] coefficient; ratio; modulus; quotient; factor
-
Fpga and dvb standard are introduced firstly, dvb - c standard and composition of its system are analyzed completely, development of modulator structure and dvb - c digital modulator composition are presented, more over, analysis of respective modular are given. then, principle of dvb - c digital modulator system are presented, they are error control technique 、 mqam 、 nyquist rule and root raised cosine filter 、 window design method for fir filter 、 multi - rate signal processing ( integer interpolating, conversion of fractional sampling, equal conversion of net structure, polyphase structure for filter, poly - phase structure for interpolator, multi - stage implementation of samplying conversion ) 、 distrubited algorithm 、 cic filter 、 dds 、 cordic algorithm
接著,專門利用一個章節闡述了dvb - c前端調制系統原理,他們了差錯控制技術、多進制調制( mqam ) 、 nyquist準則與平方根升餘弦濾波器、有限沖擊響應濾波器的窗函數設計法、多抽樣率信號處理包括(整數倍內插原理、分數倍抽樣率轉換、網路結構的等效結構、濾波器的多相表示、內插器的多相表示、抽樣率轉換的多級實現) 、分散式演算法、 cic濾波器、直接數字頻率合成( dds ) 、 cordic演算法。A novel communication receiver which uses lapped transform ( lt ) incorporating modified median filter ( mmf ) algorithm is designed for narrow - band interference excision. the lt domain mmf algorithm takes full advantages of the direct sequence spread spectrum signal, as well as the characteristics of lt, performing the transform domain filtering twice. the first filtering locates the position of interference and mitigates most of them. the second filtering is performed in a small neighborhood of the located interference. so lt domain mmf algorithm can completely mitigate the interference without distorting the desired signal. simulation results demonstrate the improved ber performance and increased robustness of our receiver
本文採用改進的重疊變換域中值濾波演算法進行變換域抗干擾處理.該演算法既考慮到直接序列擴頻信號的特點,同時又利用重疊變換的特性對變換域系數進行了二次濾波.該演算法節省處理時間,並且不需要有關干擾的先驗知識,系統性能不會隨干擾頻率變化而變化,因而是一種很穩健的處理方法The study has completed the design of two - phase inverter and made up of the two - phase inverter - motor system for experimental use it is a variable frequency adjustable speed system with a open - loop control of rotational speed, which consists of voltage - controlled oscillator circulating assign device inverter circuit and two - phase induction motor a accurate mathematical model is set based on the whole system, and simulator program of dynamic and steady condition is established, which is used to calculate the dynamic and steady performance by kron and symmetrical coordinate converter by simulator calculation and experimental research with specific parameter of the system, a comparison is made between predicted and experimental characteristics, experimental measurements are shown to compare closely with corresponding theoretical result it is compared with some variable frequency adjus table speed system comprising inverter and single - phase induction motor from the system efficiency torque pulsation and the effect of two - phase inverter capacitance based on the conclusion, harmonic cancellation pulse width modulation control of a two - phase inverter - fed induction - motor drive system is researched, which cancelled the low harmonic and improve the system performance
通過對電機的kron變換和對稱分量變換,建立了系統較精確的數學模型,編制了系統動態及穩態運行的模擬計算程序分別計算系統的動態和穩態性能。通過對系統的具體參數進行了模擬運算和實驗研究,實驗和模擬結果進行比較,說明實驗和理論較為一致,並從系統效率、轉矩脈動及兩相逆變器電容的影響等方面與各種逆變器和單相異步電動機組成的變頻調速系統加以比較。在此基礎上,對兩相逆變器供電-異步電動機系統使用諧波抑制pwm控制進行了研究,由於減少了低次諧波,改善了系統性能。There is difference frequency measurement requirement for every part of pid regulating, difference between dynamic quality and static quality in response time and accuracy. according to these, it use the interrupt functions and high - speed counter of the simens s7 - 200 plc cpu226 basic unit and some peripheral circuit to measure frequency ; in software designed, the procedure frame of hydraulic - turbine governor and disperse process of parallel pid are analyzed, an improved pid algorithm is adopted to realize a pid regulation mode with variable structure and parameters ; the mechanical liquid - pressure system of the hydraulic - turbine governor is with electric - hydraulic converter unit of step motor. according to the drive character of five phase of response step motor, a variable frequency regulated voltage driver unit is designed in order to realize interface between plc and driver of step motor
本文利用s7 - 200plc自身的特點設計了頻率測量單元,根據pid調節各個環節的特點,以及調速器動態特性、靜態特性對頻率測量的實時性和精度要求的不同,利用s7 - 200plc基本單元中內置的高速計數器以及相應的外圍放大整形、分頻電路,實現了水輪發電機組頻率的測量;在軟體上,對微機調速器的整個程序框架、並聯pid的離散化過程進行了分析,選用改進的pid演算法實現了變參數、變結構的pid調節模式;調速器的機械液壓隨動系統具有步進電機電液轉換元件,採用五相反應式步進電機,根據其驅動特性設計了變頻調壓驅動器,實現plc與步進電機驅動器之間數字介面。In the section of experiment, we focused on the research of optical system of optical parameter oscillation, computer controlling data sampling closed - circuit system and technology of computer controlling feed - back. in the section of optics, we used present condition to do the experiments about optical parameter effect and got a series of characteristic curve on power transition efficiency and output power
本文的實驗部分主要側重於智能化光參量系統的光學部分、計算機控制數據採集閉環系統以及計算機控制反饋技術的研究。在光學部分,本論文利用現有實驗條件進行了參量振蕩器頻率調諧的研究,得到了調諧曲線,並做了輸出參量光的能量轉換效率以及輸出功率的實驗,得到一系列特性曲線。To solve it, the differential equation set is transformed by fourier transform and the dynamic differential equation in the form of matrix is educed. the calculation formulas of frequency response function of vehicle vibrating system, acceleration power spectrum density function are put forward
用分析力學法建立整車動力學模型,推導出以矩陣形式表示的運動微分方程,並通過傅氏變換給出汽車動力學系統的頻率響應函數、加速度功率譜密度函數的計算公式。Author, starts from the one - way wave equation of wavefield extrapolation, research the relationship and transform condition of wavefield extrapolation operators, and propose the steady variational reference slowness rytov approximation general screen wavefield extrapolation operator ( vrselrf ) which can adapt severe lateral velocity variations, in frequency - wavenumber domain, and the improved wavefield extrapolation scheme, also give the method to improve the computation efficiency. the achievement establishes the theoretic basis of the whole research
首先,從波場延拓的單程波方程出發,系統地研究了頻率波數域的波場延拓運算元之間的相互關系和轉換條件並在此基礎上提出了能適應劇烈橫向變速的頻率波數域穩定的變參考慢度rytov近似廣義屏波場延拓運算元( vrselrf )和部分波場延拓改進方案及提高運算效率的措施,為整個研究打下理論基礎。The main work includes : for the torsional vibrations of a rigid disk on saturated media, first, the dynamic governing equations are solved by the use of hankel transform and the general solutions in the hankel transform fields are formulated. then, considering the mixed boundary - value condition, the dual integral equations of the torsional vibrations of a rigid disk on saturated grounds are obtained, which can be reduced to the fredholm integral equations of the second kind and solved by numerical procedures. consequently, the dynamic compliance coefficient curves and the torsional angle amplitude curves versus the dimensionless frequency are presented and contrasted to that of the elastic one
在前人研究的基礎上,本文基於陳龍珠等曾提出的一組實用飽和土波動方程,用解析或半解析的方法首次較系統而深入地研究了飽和半空間地基與基礎的扭轉振動問題,主要工作有:對于飽和地基上剛性圓板的扭轉振動,作者首先採用hankel變換求解了動力控制方程,得到了該控制方程在hankel變換域內的通解,然後由混合邊值條件建立了飽和地基上剛性基礎扭轉振動時的對偶積分方程,並將其化為易於數值求解的第二類fredholm積分方程,用數值方法計算了基礎的動柔度和扭轉角幅值與振動頻率的關系曲線,並將其與單相彈性介質情況進行了對比分析。In this paper, we study inversionless lasing of frequency up - conversion in an open v - type system with incoherent pump. making theoretical analysis and numerical calculation by density - matrix equations of motion, we derive the conditions for the onset of lwi and discuss the effects of the parameters of the system, the detuning of driving field and probe field on the gain, and discuss nonlinear effect in the frequency up - conversion regime. we also give stability and transient analysis
本論文研究了具有非相干泵浦的開放v型系統頻率上轉換無粒子數反轉激光,利用密度矩陣運動方程,通過理論分析和數值計算,得出該系統產生無粒子數反轉激光的條件,討論系統各參數的變化和驅動場與探測場的失諧對激光增益、色散和粒子數差的影響,還討論了頻率上轉換區域的非線性效應,分析了增益的穩定性及系統的瞬態演化過程。The electrical damping within the whole subsynchronous frequency range is calculated. the impacts of the unit interaction factor between hvdc and turbine generator, the dc power level, the firing delay angle and the parameter settings of hvdc controller on the have the potential danger of subsynchronous oscillation
在整個次同步頻率范圍內,計算得到了系統電氣阻尼,並詳盡地分析了同步發電機與hvdc的耦合程度、直流輸送功率水平,換流閥觸發角大小以及控制器參數等因素對系統電氣阻尼的影響。Based on the unified recursive formula, the four algorithms included in this study are the central difference method, the newrnark ' s method, z - transform method, and duhamel ' s step integral method. the accuracy, the phase and other existent problem are studied in this paper. it is proved in this paper that the recursive parameters b1and b2are relate to the poles of theoretical transfer function
分析中可以發現,中心差分方法, newmark中點加速度方法、 z變換方法及duhamel逐步積分法在精度范圍內其計算相位是沒有畸變的,中國地震局工程力學研究所頃土學位論文一但是中心差分方法, newmark中點加速度方法隨著采樣間隔及系統自振頻率的增大,系統的固有自振周期被改變,其傳遞函數的共振區域與理論傳遞函數的共振區域會發生分離。( 3 ) the conventional interpolated dft algorithms are analyzed. a new method, which estimates frequency with high precision and fast rate compared with the mentioned methods for the real single tone based on dft, is presented
( 3 )在分析常規的插值演算法基礎上,提出了一種單信號的快速插值頻率估計方法,只需三個fft變換系數的實部構造頻率修正項,計算量低。The use of digital radio transmission and the advanced handover algorithms between radio cells in gsm networks allows for significantly better frequency usage than in analogue cellular systems, thus increasing the number of subscribers that can be served
Gsm網路使用數線傳輸和先進的無線越區切換演算法,可以得到比模擬蜂窩系統好得多的頻率利用,因而增加了服務的用戶數。In the section 1, we have introduced the background and the recent advance of the flattened gaussian beam ; in the section 2, for the first time, we have calculated the type - i and type - ii shg conversion efficiency and simulated curves versus the crystal length, the pumping light polarization rate, the order of the flattened gaussian beam and the pumped power intensity, we obtain ed that the highest efficiency was influenced by the order and the polarization rate of the pumped flattened gaussian beam
從三波耦合方程及clbo晶體的光學特性出發,討論了以平頂高斯光束入射時穩態的三波耦合方程的大信號倍頻解(包括類及類相位匹配的倍頻解) 。計算了其在clbo晶體上的倍頻轉換效率與晶體長度,基波偏振分量比,基波階數及泵浦波強度之間的相互影響關系曲線。得出影響平頂高斯光束的最高轉換效率的因素是基波的階數n和泵浦波的偏振分量比d 。So power systems harmonic analysis is a significant aspect of power systems research. power system harmonic analysis was realized usually with fast fourier transform ( fft ), but the method exits spectrum leakage, and can not analyse all harmonic parameters exactly, such as frequency, amplitude and phase, in particular has big phase error
電力系統諧波分析通常都是通過快速傅立葉變換( fft )實現的,但是這種方法存在柵欄效應和頻譜泄漏,使計算出的諧波參數即頻率、幅值和相位不準,尤其是相位誤差很大,無法滿足準確的諧波測量要求。Firstly, wall ’ s transfer matrix is deduced by laplace transformation based on 3r2c thermal network model. secondly, frequency response of transfer matrix is calculated. thirdly, we make the frequency response of transfer matrix of stimulation model equate the theoretical frequency response of wall transient heat conduction by applying appropriate identification algorithm, from which we can obtain every polynomial ’ s coefficient of model transfer function, then each parameter of resistance and capacitance is calculated by appropriate optimization algorithm
首先,根據模擬熱流網路模型用拉普拉斯變換推出墻體的傳遞矩陣;然後,計算傳遞矩陣的頻率響應;最後,採用頻域回歸方法求出模型傳遞函數各次項的系數,進而通過一定的優化演算法確定模型的各個熱阻、熱容參數,使通過模型建立的多項式s -傳遞函數與墻體瞬時傳熱的理論超越s -傳遞函數完全等價。The second part is a detector which is used to detect the distribution of voltage on the patient ' s brain surface from all different directions. the third is a mixed signal processor ( c8051f020 ) which is used to control the other parts of the system and display some necessary information and convert the voltage signals into digital signals, as well as transmit the acquired data to the computer. the fourth is computer with eit software which is used to analyze and process the received data and construct a picture for the brain edema and haematoma on screen
32通道電阻抗斷層成像系統由4個部分組成:第一部分是正弦波恆流源,用來產生注入大腦的激勵電流;第二部分是電位信號的提取與轉換,用來提取當激勵電流注入時,在大腦表面形成的電位分佈信號;第三部分是數據採集與控制系統,用來控制激勵電流的頻率,注入方向,注入強度,控制採集大腦表面的電位分佈信號,並且將這些採集的電位分佈數據傳到pc機;第四部分是計算機eit成像軟體,用來接收下位機的電位分佈數據,並且對這些數據進行分析計算,重建電阻抗圖像。At the same time we obtained that the shg conversion efficiency of the flattened gaussian beam is higher than that of the gaussian beam under the same condition ; in section 3, we have computed the theoretical conversion efficiency of the thg on the flattened gaussian beam, where we also have worked out the type - i and type - 11 ( 1 ) thg conversion efficiency curves versus the same effectors, and found the flattened gaussian beams thg conversion efficiency is higher than that of the gaussian beam too ; in the section 4, we have simulated the field distribution of the shg and thg wave on the flattened gaussian beam
在相同條件下,得出了平頂高斯光束的倍頻轉換效率高於高斯光束的倍頻轉換效率;第三章對平頂高斯光束在clbo晶體上的類和類混頻轉換效率與其影響因素的關系進行了數值模擬和計算,並同高斯光束進行比較,同樣得到混頻時,平頂高斯光束的轉換效率高於高斯光束的混頻轉換效率的結論;第四章模擬計算了平頂高斯光束的倍頻、混頻波橫向光場的分佈形式,得到了諧波場仍為均勻平頂高斯光束的結果。The results show their efficiency and validity. chapter 2 first reviews the basic theory concerned with image wavelet transformation, which includes the wavelet multi - resolution analysis theory, the discrete wavelet transformation and the two dimension discrete wavelet transformation ( mallat algorithm ), and analyzes the space and frequency distributing characteristics of image wavelet coefficients
第二章首先詳細介紹了圖像小波分析的基本理論,其中包括從小波多解析度分析理論開始到離散小波變換再到圖像的二維離散小波變換即malat演算法,並著重分析了圖像小波變換系數的空間和頻率分佈特點。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。分享友人