推頻值 的英文怎麼說

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。

The thesis focus on the numerical analytical method of curved broadband wire antennas. first, the paper introduced the development of broadband antennas, the common measures to broaden antennas " bandwidth and the study on curved antennas. second, the generalized halen integral equation ( mei ' s equation ) was derived based on the three basic equations of wire antennas by two means and its numerical solution method was discussed

本文就曲線寬頻帶線天線的數值分析方法展開研究，首先介紹了寬頻帶天線的發展，實現天線寬頻帶的常用方法和曲線天線的研究現狀，然後在直線加載天線滿足的方程的基礎上用兩種方法推導了曲線天線滿足的推廣的海倫積分方程（ mei 』 s方程） ，討論了不同基函數下方程的數值解法。

The signal we named it fundamental wave ; according to the fundamental wave, coefficients of the fundamental wave can be lined in a sequence. when the unique of the dissolve of the fundamental wave can be confirmed, the sequence of the coefficients can be regarded as one of representation forms of the signal itself ; theory of dissolvable signal shows that when order of the matrix of fundamental wave sampling equals to number of fundamental waves, the sequence of the sampling values from sampling points must be matched one by one with the sequence of the coefficients of fundamental waves. the sampling composed by sequences of the sampling values must be full sampling ; the relevant deductions of the theory of dissolvable signal shows that when sampling the signal, sampling frequency must be lager than the ratio of the number of fundamental waves to the occupation time of the fundamental waves ; to band - limited signals, when the fundamental wave is a sine signal, the results from the relevant deductions of theory of dissolvable signal is coherent to the classic sampling theory

本文通過分析認為，當信號集中的任一信號可表示為一系列已知信號的線性代數和時，信號集便構成可分解信號集，已知信號稱為基波信號；對可分解信號而言，基波系數構成一序列，當對指定的基波信號集分解唯一確定時，系數序列本身便是信號的一個表示；可分解信號采樣定理指出當基波樣值矩陣的秩等於基波數時，則由采樣點處的采樣樣構成的樣值序列必與基波系數序列一一對應，從而由該樣值序列構成的采樣必為完全采樣；可分解信號采樣定理中的推論指出，對信號集進行采樣，采樣頻率必須大於其信號分解的基波數與其對應時長之比；對有限帶寬信號，若基波信號為正弦信號時，由可分解信號采樣定理推論給出的結論與經典采樣定理一致。

Some by - products of this work can be used as routine tools in the uv laser laboratory. commercial video ccd cameras are used to image uv laser and soft x rays, window glass as a fluorescer is used to indirectly measure the uv laser beam profile with high energy density, and a special glass which permits uv light to pass through while absorbs the visible, is introduced into the uv beam profiling in strong visible stray light environment

實驗中發展了一些測量技術，例如用可見光視頻ccd直接測量紫外激光的光束分佈和激光等離子體產生的x光二維圖象，利用窗玻璃作為熒光體測量能量密度較高的紫外光束分佈，利用可見吸收紫外透射玻璃製成的衰減器測量有嚴重背景光的紫外光束分佈，可以作為實驗室的常規測量工具，並有一定的推廣價值。

The maturity of stream media and cdn technologies will surely give a revolutionary impetus to broadband content and even to the entire broadband industry. they will provide end users with internet - based information services such as multimedia news release, on - line direct broadcast, network - based advertisement, e - commerce, vod, distance education, remote medicine, internet - based radio station and videoconferencing, and yield a comfortable profit to the value chain of the broadband industry, including operators, icps and isps. 2

流媒體技術的發展和內容分發平臺的成熟，必將為寬帶內容提供革命性的推動力，必將喚醒整個寬帶產業，為最終用戶帶來網際網路多媒體新聞發布、在線直播、網路廣告、電子商務、視頻點播、遠程教育、遠程醫療、網路電臺、實時視頻會議等網際網路的信息服務，給運營商、內容提供商、服務提供商等整個寬帶產業價值鏈帶來豐厚的利潤。

As we have introduced a multilevel decision method with discriminator detection to improve the error rate performance, the deducing and analyzing for this method are present in this article. the theoretical error rate and the monte carlo simulation result are showed in figure to compare the system error rate performance affected by different premodulation filter

在系統誤碼模擬中引入了一種有助於改善誤碼性能的鑒頻加多電平判決的解調方法，文中對此方法也進行了詳細的推導和分析，並給出根據此方法計算出的誤碼理論值，結合系統誤碼性能的蒙特卡羅模擬值，對比分析各種預調濾波器對系統誤碼性能的影響。

According to the guidline, two nd : yag lasers have been designed and set up, one is end - pumped by lower output power ld using a selfoc micro lens, and the other is end - pumped by high output power ld using a pair of lenses are designed, and the characteristics such as output power and power stabilization of both solid - state lasers are investigated. thirdly, when an empty liquid crystal cell is inserted in the cavity of the nd : yag laser pumped by high power ld, the laser can operates in single axial mode. finally, according to the relationship between the laser output power and the longnitudinal a ld - end - pumped nd : yag laser sensor for displacement measurement has been investigated theoretically and demonstrated experimently, the results indicate that when the mean radius of pumping inside the laser cavity is far less than that of the oscilating laser mode, the exponential of the output power is a gauss function of the longitudinal positon of focused spot of ld pumping beam, both the measurement range and the sensitivity are dependent on the incident pumping power, as the incident pumping power is increased, the measurement range is enlarged and the sensitivity is improve d

本文首先介紹了ld泵浦nd ： yag激光器的發展狀況、主要特性及其應用，從四能級速率方程出發，推導了ld泵浦nd ： yag激光器的閾值、輸出功率和斜效率的表達式，並簡述了激光器的工作原理、結構型式和倍頻方法；其次，以空間相關的速率方程為基礎，提出了ld端面泵浦nd ： yag激光器的設計方法，給出了一定泵浦耦合方式下，振蕩光模尺寸、最佳輸出耦合率、泵浦光模尺寸、泵浦光焦斑位置等參數的選取依據，以此為依據，設計了自聚焦透鏡耦合小功率ld泵浦nd ： yag激光器和透鏡組耦合高功率ld泵浦nd ： yag激光器，對激光器的輸出功率和功率穩定性等特性進行了實驗研究；再次，在帶尾纖輸出的高功率ld泵浦nd ： yag激光腔內插入一隻空液晶盒，觀察到了激光器以單縱模運轉；最後，根據泵浦光焦斑端面位置對激光輸出功率的影響規律，提出了ld端面泵浦nd ： yag激光位移傳感新方法，並進行了理論和實驗研究，研究結果表明：當激光晶體內泵浦光平均光斑半徑遠小於振西安理工大學碩士學位論文蕩光束腰半徑時，激光輸出功率的自然指數與泵浦光焦斑的縱向位置成高斯變化規律，測量范圍和靈敏度依賴于泵浦功率，隨著泵浦功率的增加，測量范圍擴大，靈敏度提高，當端面泵浦功率為7 . 24w （最大輸出功率為1 . 926w ）時，激光位移傳感器的測量范圍和靈敏度分別是13 . 045mm和0 . 148mw / pm 。

In hardware, we choose anti - disturbance photoelectric isolative sensor, take rc filter to resolve high - frequency for anti - disturbance. in software, we adopt arithmetic of recursion mean value to collective signal values to resolve low - frequency ac and pinnacle pulse disturbance

在硬體方面，選用抗干擾能力強的光電隔離電量傳感器，並採取rc濾波抗干擾措施解決中高頻干擾問題；在軟體方面，對採集到的信號量採取遞推平均值演算法，解決低頻交流和尖峰脈沖干擾問題。

The results indicated that the generation of trailing - vortex of downstream adjacent vanes could be restrained effectively by upstream wake when the passing frequency and the amplitude of wake defect satisfy some conditions, associated with a significant enhancement of time - averaged aerodynamic performances : loss coefficient reducing 40. 2 % and the ratio of loading coefficient and loss coefficient increasing 93 %

研究表明：滿足一定通過頻率和虧損幅值條件的尾跡能夠有效抑制下游相鄰葉排尾緣渦的生成，達到控制或是推遲附面層非定常分離的目的，從而使得流場時均性能大幅度的提高，損失系數降低了40 . 2 % ，功損比增加93 % 。

Considering the similitude law for shaking table test, we study the test results and obtain some conclusions which are a ) generally, the silty soil in test box liquefies and the liquefied time has relation with the amplitude of acceleration, b ) when the intensity is on and above eight degree, the silty soil deposit will be liquefied dramatically, c ) the relationship of the pore water pressure is relevant to the cycle loading which represents when the cycle loading ranges from little to great, the relationship is represent as a concave curve, or else as a protruding curve and tends to stability. ( 3 ) based on the triaxial compression test and the resonant column test, some studies are made such as a ) the duncan - chang parameters of constitutive model, b ) the dynamic shear modulus ratio and c ) the damping ratio of the site soil deposits. in order to deal with the test data, a computer program is compiled

（ 2 ）利用小型振動臺進行了k _ 0固結狀態下粉土的振動液化模擬研究，通過分析正弦荷載作用下的試驗資料，驗證了粉土的孔隙水壓力增長模式的合理性；從微分方程推導了基於土體振動臺模型試驗的相似律，並從模型實體、孔壓時程曲線和相似律等方面做出了分析，得出了如下結論：在小型振動臺試驗中，模型箱中的粉土都發生了液化，液化的時刻和輸入加速度幅值有關，而對頻率的變化不太敏感；粉土在相當於8 9度地震烈度的加速度幅值作用下可能產生嚴重的液化；孔壓的增長曲線形狀與施加的荷載有關：當施加荷載為由小到大的形式時，曲線形狀為上凹的曲線；當施加荷載為等幅的正弦荷載或荷載幅值由大到小時，曲線形狀為上凸的曲線，且逐漸趨于穩定。

In this paper, they are set forth at first that the kinds of computer - simulation of electronic devices, the development and the requirements of mosfet ' s model and the way of gain the models " parameters, the dc models have been bui it in chapter 2 and the models of big signals have been deduced in chapter 3, they are different from the equivalent circuit models in the traditional software pspice that they come from the numer i ca i - s i mu i at i on wh i ch is based on the essence equat i on, so the precision of simulation is enhanced ? mosfet ' s small signal models of low frequency, intermediate frequency and high frequency have been built in chapter 4 and chapter 5, although the equivalent circuit models in pspice are used for reference to bui id them, they have their own characteristics which are analyzed at a i i kinds of situations, so that the simulation software for mosfet can be written according them and it i s a i so benef i c i a i for us to catch the gen i us character i st i cs of mosfet and to d esign all kinds of applicable devices the correctness of the models is simply proved in chapter 6

本文首先介紹了電子器件計算機模擬的分類、 mosfet的建模發展動態、對器件模型的要求以及模型參數的提取方法。在第二章中建立了mos晶體管在直流端電壓條件下的工作模型；第三章推導了mosfet的大信號模型，這兩類模型不同於傳統模擬軟體例如pspice中的等效電路模型，而是從模型方程出發，採用數值模擬的方法，提高了模擬的精度。第四章和第五章分別建立了mos晶體管低頻、中頻、高頻的小信號模型，雖然借鑒了pspice模擬軟體中用等效電路模型的方法，但是本文分別討論了準靜態和非準靜態時器件的本徵部分以及包含非本徵部分工作于低頻、中頻和高頻條件時的模型，可以根據這些模型編寫相應的模擬軟體，這樣在做器件的模擬分析與器件設計的時候，就可以利用模擬軟體逐步深入地分析器件在不同的條件下和器件的不同部分在工作時的各種小信號特性，有利於抓住器件工作的本質特性，設計出符合要求的各類通用和特殊器件。

In the four parameters the frequency of excitation force is most significant to the horizontal and vertical velocity of seedlings. the amplitude of excitation force is less significant

四個因子中，頻率對缽苗的推送速度影響最為顯著，其次是激振力幅值f 。

The performance of vibration and movement of seedlings is validated in the whole vibration plate simulation. an orthogonal experiment is designed for analyzing the effect that the four parameters ( f, co, a, k ) act on horizontal and vertical velocity of seedlings

首先驗證虛擬模型的振動性能與物理原型基本相符，進一步採用正交試驗，考察四個因子（激振頻率山、激振力幅值f 、彈簧剛度k及彈簧傾角）對缽苗推送速度的影響。

The application of multi - level delay charging method has change the conventional charging method and increase the effective energy in downgoing elastic wave, which has unique effect in increasing the bandwidth of effective wave, resolution, s / n ration and interference attenuation and is worth to propagate

多級延遲爆炸技術的應用，改變了傳統的激發方式，提高了彈性波下傳的有效能量，對提高有效波頻帶寬度、在提高解析度、信噪比、壓制干擾各方面，都具有獨特的作用，具有很好的推廣價值。

A series of standard solution made up with standard substance of sodium carbonate, and combusted in a high - frequency induction furnace with pure oxygen, and the amount of total carbon was measured by infrared absorption

摘要以碳酸鈉為基準物質，配成一系列標準溶液，在通有純氧氣的高頻爐中燃燒，紅外吸收法測定碳含量，繪制校準曲線，測定矽中總碳量，與推薦值基本一致，方法準確、結果滿意。

Firstly, this paper makes a detailed study on the field control bus system ( pcs ), including the characters of pcs by comparing fcs and dcs, model networking of pcs and several popular field bus, then put forward a question for discussion combining embeded internet technology and field bus and measure and control networking model based embeded internet technology is constructed. secondly, it studies embeded system including the core of hardware ? mbeded microprocessor and real time operation system. thirdly, the method of realizing embeded internet is discussed for emphasis, and difficulty of ehernet application in industry measure & control system is analysed. an instance of measure & control networking system based embedded ip is given. finally, the author designed a networked remote video surveillance system based embedded web server, c / os - ii is sacled and ported into the embedded microprocessor at89c51. based on the c / os - ii rtos, tcp / ip protocol suite and application program is designed in detail. the system w orks well that improves that the embedded internet technology will be widely used in modern measure & control networking system and has extend values

本文首先分析了現場總線系統（ fcs ）與傳統集散控制系統（ dcs ）相比具有的特點、 fcs的網路體系結構，介紹了幾種流行的現場總線，提出了將嵌入式internet技術結合現場總線構建現代測控網路的課題；在此基礎上，構建了基於嵌入式internet技術的測控網路結構模型；深入研究了嵌入式系統的核心硬體?嵌入式微處理器，通過對比普通操作系統，描述了嵌入式實時操作系統的特點；重點研究了實現嵌入式internet的四種實現方法，並分析了以太網在工業測控系統中應用的難點，給出了一個基於嵌入式ip的網路測控系統實例；最後，研究與設計了一個基於嵌入式web服務器的遠程網路視頻監控系統，該嵌入式web服務器利用目前成熟的嵌入式實時操作系統c / os - ，通過對c / os -進行適當的裁剪、修改與移植，在at89c51嵌入式微處理器上實現了tcp / ip協議棧及應用程序，系統的成功運行證明了本文研究成果的有效性，也表明嵌入式internet技術在現代測控網路系統中具有廣闊的應用前景和推廣價值。

The auto - spectrum is attached to linear phase, the amplitude - frequency drawing is got according to the arithmetic of bi - spectrum, then the equivalent is educed, the conversion relation is attained

該方法通過對自譜添加線性相位，根據雙譜的數值估計演算法計算獲得雙譜在三維空間的幅頻圖，通過推導雙譜與自譜估計演算法之間的等價關系以及所得的幅頻圖來實現兩者之間的相互轉換。

The topologies family include single four - quadrant power switch mode, push - pull mode, half - bridge mode, and full - bridge mode circuits. taking full - bridge mode circuit as an example, the operational mode, steady principles, transient voltage feedback control strategy of the converter are investigated. the output characteristic curve, the design for the key circuit parameters and the reference sinusoidal circuit which is synchronous with the signal of n or 1 / n times line voltage frequency are given

該電路拓撲族包括單四象限功率開關式、推挽式、半橋式、全橋式電路，以全橋式電路為例分析研究了這類換器工作模式、穩態原理與電壓瞬時值反饋控制策略，給出了變換器的外特性曲線、關鍵電路參數、與電網電壓n倍頻或n分頻信號同步的基準正弦電路的設計。

Abstract : the paper mainly introduces the application that the high voltage inverter in the oil field pump and joint electricity effect is clear, and possesses application and dissemination value

摘要：本文敘述了高壓變頻器在油田注水泵上的應用，節電效果明顯，具有推廣應用價值。

During the low strain dynamic test of the foundation pile, the adoption of the velocity sensor to the direct measurement of the relative displacement of the pile head is helpful to reducing the improper dependence upon the measured intrinsic frequency valuesof the pile soil system in calculating vertical bearing capacity of the single pile, and is hence conducive to raising the accuracy of the calculated vertical bearing capacity of the single pile

基樁低應變動測中，採用速度傳感器直接測出樁頭的相對位移，在推算單樁豎向承載力時，有助於降低對樁土體系固有頻率測定值的過分依賴，從而有利於提高單樁豎向承載力推算值的準確程度。