零頻值 的英文怎麼說
中文拼音 [língbīnzhí]
零頻值
英文
zero-frequency quantity-
1 m 0. 5, the phase - shifted angle 6 is controlled in term of sine law which makes the magnitude of resonant voltage track a reference sine voltage, and the resonant voltage is rectified, filtered, inverted and then the better sine - voltage output is obtained, theoretical analysis and experimental results show that for the resistive load and inductive load, the switches of leading leg of the phase - shift - controlled circuit are always turned on at zvs, and ones of lagging leg are turned on at zvs ( < 0 ) or turned off at zcs ( ( > 0 ), moreover, all switches in the low - frequency inverter are always turned on and off at zvs, the measured circuit efficiency for rated load reaches up to 88 %
從功率單向流動角度出發，提出了一種lcc諧振型恆頻移相單相高頻鏈逆變電路拓撲，在調制系數0 . 1 m 0 . 5情況下，控制移相角按正弦規律變化，使諧振電壓脈沖列的幅值追蹤參考正弦電壓信號，經過整流、濾波、低頻逆變，從而獲得正弦度較好的輸出電壓。理論分析和實驗結果證明對于阻性負載或阻感性負載，移相全橋具有超前橋臂零電壓開通，滯后橋臂或者零電壓開通（ _ 0 ）或者零電流關斷（ _ 0 ）的軟開關特性，而低頻逆變器的各個開關均實現零電壓條件下的開通與關斷。Propagation of spectra affected by third - order dispersion in dispersion - decreasing fiber near zero dispersion wavelengths was studied by means of numerical simulation
摘要為探討三階色散對脈沖傳播的意義，用數值模擬的方法討論了在色散緩變光纖中零色散波長附近三階色散對脈沖頻譜演變的影響。Thirdly, in the environment of labview, several kinds of vis used for sensor signal test are designed, including wave generation, time domain measurement, filter disposal, frequency analysis, etc. after that, wavelet analysis in the application of one - dimensional signal de - noise is studied, threshold and translation invariance wavelet de - noise are realized, and wavelet de - noise vi for zero drift signal of the fiber optic gyro in fcs is designed using labview
接著，在labview環境下開發了多種用於傳感器信號測試的虛擬儀器，具有波形發生、時域測量、濾波處理、頻譜分析等多種功能。隨后，研究了小波分析在一維信號消噪中的應用，實現了labview環境下的閾值法和平移不變量法小波消噪，並利用labview設計了飛控系統中光纖陀螺零漂信號的小波消噪儀。So this part is dealt with separately. dcpm method is employed to improve the quality of image coding with making full of the relativity of the wavelet coefficients. according to the different importance degree and vision character of the high frequency wavelet coefficients, different thresholds are applied to remove small coefficients ; then mannos module are applied to remove the visual redundancy ; in order to produce more zero - tree, horizontal and vertical wavelet coefficients are transformed accordingly to improve the compression ratio
對于小波變換后的小波系數的高頻部分，根據其分佈特性和人眼的視覺特性，採用視覺模型對零樹量化過程的閾值進行修正，有效地去除視覺冗餘；對各高頻子圖採用多級樹集合分割的零樹編碼方法，有效地利用系數編碼剩餘符號，進一步提高壓縮比。Third, mensurated the front axle ' s load - time history when truck was running on general tar - paved roads, mountainous roads and the proving ground enhancement roads, second sampled and pretreated to the load - time history with rpc software of mts corporation, acquired the relationship of the frequence of the mean and amplitude load, obtained the zero mean equivalent loads using goodman experiential fatigue equation, acquired the weibull distributing functions of equivalent loads of respective roads
第三，測定了汽車前橋在一般瀝青公路、山區公路和試驗場強化試驗路面的載荷時間歷程。對載荷時間歷程進行了二次采樣和數據預處理。採用雨流計數法得到了各路面的載荷均、幅值的頻次關系，並根據goodman經驗疲勞公式，得到了零均值的等效載荷及相應的頻次。When the frequency approaches zero, the factor approaches zero correspondingly ; 2 ) the amplitude of interaction factors changes with the incident angle of rayleigh waves and reaches maximum when is zero. moreover, with the increase of, the wave period shortens apparently ; ( 3 ) the amplitude of interaction factors decreases as the pile spacing increases and approaches to zero when the pile spacing is 15 ; 4 ) the amplitudes of interaction factors increase clearly with the increasing stiffness ratio of pile to soil ; 5 ) the lat eral seismic response of fixed - head pile groups is much smaller than that of free - head pile groups. moreover, the pile - group effects induced by rayleigh waves can be neglected ; 6 ) the lateral seismic response of piles at different location differs from each other
得到了以下結論： 1 ）樁的相互作用因子隨頻率呈周期性變化，在振動頻率比較低的情況下，樁的橫向相互作用因子也較低，當頻率趨近於零時，相互作用因子也趨近於零； 2 ）樁的相互作用因子的幅值隨瑞利波入射角度的變化而變化，在= 0情況下幅值最大，且隨入射角度的增加，波動的周期明顯縮短； 3 ）樁的相互作用因子的幅值隨著樁與樁間距的增加而減小，至s d = 15時，樁的相互作用因子基本趨近於0 ； 4 ）在頻率比較低時，相互作用因子幅值隨樁土相對剛度比的增加而顯著增加； 5 ）樁頂固接可以有效地降低群樁的橫向地震響應幅值，由瑞利波產生的群樁效應可以忽略不計； 6 ）群樁中不同樁位的樁的橫向地震響應是不同的，每根樁所在的樁位對其橫向地震響應有很大的影響；刀樁數的增加並不能減小樁的橫向動力響應。Judgment of the point of zero passage is the key factor involved, and a higher sampling frequency should be adopted when the method is applied on situations of large signal amplitude
其中過零點判定為關鍵技術，當用於信號幅值較大場合時應盡量提高信號采樣頻率。The following algorithms have been proposed and tested in the thesis : 1 frequency selective fading : combine the isomorphism between the input space and the output space and propose a new approach to blind equalization of the channel. compared with conventional methods, the new approach offers lower computational complexity, better performance, and more robust against the over - determination of the system order ; 2 time selective fading : a new approach to the equalization of time selective channel based on the zero - forced equalizer is proposed which is more simple in its structure of algorithm ; 3 time - varying channel : using the instantaneous mean value changes of the output signal to extract the information of channel variations and model it using ar model, kalman filter is then employed to track channel variations, it bears faster ability in tracking the variation of tv channels ; based on the isomorphism between the inputs and the outputs and some of the approaches using in mimo system, a new algorithm of equalization of simo time - varying channel is proposed, which also share the merits of being robust against the over - determination of the system order ; model the time - varying channel using the multi - resolution decomposition wavelets, and then a blind identification method based " on the model is proposed ; at last, a new model for equalization and identification of mimo system is proposed
主要工作在以下幾個方面： 1 、針對頻率選擇性衰落通道：結合輸入輸出空間同構關系提出一種新的頻率選擇性通道均衡方法，與傳統方法相比，該方法計算量更小，收斂速度更快，性能更優，且對系統階次的過確定表現穩健，具有實際均衡應用價值； 2 、針對時間選擇性衰落通道：提出一種基於迫零均衡的時間選擇性通道均衡方法，演算法結構簡單； 3 、針對時變色散通道：利用瞬態均值曲線提取通道時變信息，對之ar建模，利用卡爾曼濾波器跟蹤時變通道抽頭變化，可以快速跟蹤通道變化；基於輸入輸出空間之間的同構關系以及多輸入多輸出系統的處理方法，提出了新的單輸入多輸出色散時變通道均衡與識別演算法，同樣具有對通道階次過確定保持穩健的優點；結合小波多解析度分析提出一種基於小波模型的通道盲識別演算法；研究時變的多輸入多輸出系統的盲均衡與盲反卷積問題，給出一種時變系統處理模型。The major work and achievement of this paper are presented as follows : ( 1 ) we review the main methods of audio retrieval at home and abroad
對音頻信號的短時過零率、短時能量、 mel倒譜系數等進行主要分析。提出均值mfcc系數作為音頻特徵的方法。During the research, ultrasonic signal testing system was designated by adopting transform the average value of function to nought, optimizing of collection frequency and transducer frequency
在研究過程中，採用零均值化、優化采樣頻率與探頭頻率的匹配等對超聲信號頻譜分析系統進行了標定。30 mhz measurement of quartz crystal unit parameters by zero phase technique in a pi - network - part 4 : method for the measurement of the load resonance frequency fl, load resonance resistance rl and the calculation of other derived values of quartz crystal units, up to 30 mhz
用型網路的零相位法測量石英晶體元件參數.第4部分:石英晶體單元負荷諧振頻率fl負荷諧振電阻rl的測量方法及其他石英晶體元件導出值的計算方法First, we calculate out the zero point in a simple numeral method, then we get the phase according to the fact that the symbol of phase changed is opposite in the positive - slope and the negative - slope of triangle wave. this method has the following characteristics : easy to calculate, simple to realize and high precision
首先用簡單的數值方法較準確的計算出零點時刻;進而根據三角波掃頻時正程和逆程相位變化符號相反的特性，巧妙的完成了相位計算，該方法具有計算簡單、實現方便、準確度高等特點。In the wavefield - spread area, we uses the phase - shift operator as constraint in frequency - wavenumber field, while beyond the wavefield - spread data, we uses zero point at the ends of phase - shift operator as constraint to take discrete smooth interpolation so that the resulted operator satisfies two - order smooth and the length of this operator can be selected shorter in frequency - space field
通過離散光滑插值法，在頻率波數域中，以傳播區內的相移運算元為約束，在傳播區外的運算元兩端處以零點為約束，進行離散光滑插值，使得所得運算元具有二階光滑可導性，則其對應的頻率空間域中的運算元就可以取得很短。For identical modes, the singular values are exactly one, and the singular values drop to zero as the modes move away from each other
當兩組訊號次空間相同時，奇值等於一：當二者頻率漸遠時，奇值則隨之下降趨于零。A zero - voltage starting method is brought forward which switch the starting from separate exciting to self - exciting successfully ; pll ( phase lock loop ) technology is employed to realize the frequency tracing and constant phase angle control ; igbt driving and protective circuit suitable for parallel inverter is developed, which successfully solve the problem of time compensating and overlapping regulation for the driving signals ; a novel and practical over - voltage protective method for parallel inverters is presented which effectively avoid the possible over - voltage destroy to the inverter. xu haiwen ( power electronics and electric driving ) directed by senior engineer peng yonglong
提出了一種零壓啟動的他激轉自激方法；通過採用鎖相環技術實現了逆變器工作頻率的自動跟蹤和容性逆變角度的恆值控制；設計了適用於並聯諧振型逆變器的igbt驅動與保護電路，解決了驅動信號的時間補償以及重疊角的可調問題；提出了一種新穎、實用的逆變器過壓保護方法，有效地解決了並聯型諧振逆變器過壓保護這一難題。Judging by the different magnitude and direction of the wavelet packet coefficient modular maximum, we can select the single phase - to - earth line. the method using wavelet singularity detection theory to extract the fault time is discussed. a fault distance measurement algorithm combining wavelet analysis used for separating the character from the transient fault signal with artificial neural networks used for the nonlinear approximation from the transient character to fault distance is presented
論文提出利用各個出線零序電流在頻帶上小波包系數模極大值的方向和大小的不同來實現故障選線，討論了利用小波分析的奇異性來判斷故障啟動時刻，提出將小波分析和人工神經網路結合，利用人工神經網路的非線性逼近能力，實現故障暫態量到故障距離的非線性映射，完成測距。The main results of this paper are as fellows f 1 ) illtroducing the ultrasonic technology to the rigid measurement, successful1y exploits the practical small intellectualized ultrasonic device of measuring rigidity by applying mechanical technology, electronic technology and computer science 2 ) reading clearcf displaying more various, applying more information, being easiest to accept by user because of adopting liquid crystal display ( lcd ) 3 ) theorizing the mathematical model between the signal of frequency and the rigid value on the device, possessing very importan practical significance 4 ) optimizing the every parts of the device, achieving the goals of lower wastage of energy, smaller, lighter and inexpensive 5 ) taking the measure to reduce the wastage of energy and adopting reasonable management in power supply for the device, making the device skimp more energy, prolonging the life - span of battery 6 ) utilizing the interface of rs - 232, discussing the communication between the ultrasonic device of measuring rigidity and computef, and also forecasting the foreground of advanced exploitation by user
本文工作的主要成果是： 1 ）將超聲波技術引入零件表面硬度的檢測當中。應用機、電、計算機技術，研製成功較為實用的小型智能超聲波硬度檢測儀2 ）採用lcd （ liquidcrystaldisplay ）液晶顯示，使讀數更清晰、顯示多樣化、信息量多、易於為用戶接受3 ）在理論上建立了該系統的頻率信號與硬度值的數學模型，具有非常重要的實踐意義4 ）對各元器件進行優選，達到低能耗、體積小、重量輕、價格便宜等目的5 ）採取措施降低整個系統的能耗並對系統的供電進行了合理的管理，使其進一步達到低能耗，延長了電池的使用壽命。 6 ）利用rs - 232標準介面，討論了該超聲波智能硬度測量儀與系統機進行通訊以及用戶進行二次開發的前景At present the manufacture of surface acoustic wave use the technology of the final submicron. a series of the devices of low insertion loss, high q saw rayleigh surface acoustic wave resonators or stws that insertion loss has less than 5db, load quality factor ( ql ) is more than 1000 on the quartz piezoelectric with zero of first temperature factor in the research. these difference frequencies are 60mhz, 280mhz, 739mhz and 1ghz of normal frequency and at also surface acoustic wave. using 1. 25db noise factor amplifier, careful design curcuit, good setting printed curcuit board, and using the 1ghz surface transverse wave resonator as frequency element, researching the low phase noise surface acoustic wave with sideband phase noise near ? 120dbc / hz deviating 1khz on carrier, spurious suppress with 80db
本研究採用一階溫度系數為零的壓電石英基片上製作出損耗小於5db 、有載品值因素（ ql值）超過1000的一系列低損耗、高q值聲表面波rayleigh波或stw諧振器，頻率分別為60mhz 、 280mhz 、 739mhz和1ghz等不同頻率的高性能聲表面波諧振器。並採用噪聲系數為1 . 25db的低噪聲系數放大器，精心設計電路，優化設計布置印製電路板，用標稱頻率為1ghz的聲表面波諧振器為頻率控制元件，製作出在偏離載頻1khz處的單邊帶相位噪聲近- 120dbc / hz 、雜波抑制達80db以上的低相位噪聲聲表面波振蕩器。The cyclic estimation approaches of chirp signals in additive nose or multiplicative noise are proposed, it presents a way for the parameters estimation of zero mean amplitude chirp signals. the estimation performances in the additive noise or multiplicative noise are analyzed by the first order perturbation analysis method, and the error variance expressions of the parameters estimation under large samples are derived
針對加性噪聲情況及存在乘性噪聲的情況，提出了線性調頻信號參數的循環平穩估計方法，解決了零均值乘性噪聲的信號參數估計問題，並採用一階擾動分析方法，對兩種噪聲情況下的估計性能進行了分析，推導出了各參數的估計誤差方差公式。A range of value added services are currently being provided by dvn on digital tv platform at affordable cost for channel rebroadcasts, near video on demand, on - line information, interactive advertising, tv - commerce etc. based on the prc s nationwide survey report " economic research analysis of digital set top box technology for cable tv operators " conducted by the academy of broadcasting science, sarft of china in 2002, the dvn s brand set top boxes ranked the highest in the adoption rate amongst the tv operators in china
集團已在中國十多個省市建立了二十多個數碼廣播系統，以低廉的成本向電視觀眾提供視頻點播、網上訊息、互動廣告、電視商務等一系列的數碼電視增值服務。根據中國廣播科學研究院二零零二年的《有線數字電視機頂盒技術經濟分析研究報告》 ，天地數碼的柏視通機頂盒為各地運營商選用率最高的終端產品品牌。分享友人