特定重復頻率 的英文怎麼說
中文拼音 [tèdìngzhòngfùbīnlǜ]
特定重復頻率
英文
specific recurrence rate- 特 : Ⅰ形容詞(特殊; 超出一般) particular; special; exceptional; unusual Ⅱ副詞1 (特別) especially; v...
- 定 : Ⅰ形容詞1 (平靜; 穩定) calm; stable 2 (已經確定的; 不改變的) fixed; settled; established Ⅱ動詞...
- 重 : 重Ⅰ名詞(重量; 分量) weight Ⅱ動詞(重視) lay [place put] stress on; place value upon; attach im...
- 復 : Ⅰ形容詞1 (重復) repeated; double; duplicate 2 (繁復) complex; compound Ⅱ動詞1 (轉過去或轉過...
- 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
- 特定 : 1. (特別指定的) specially appointed; specially designated 2. (某一個) given; specified; specific
- 重復 : 1 repeat; duplicate; reduplicate; iterate 2 repetition; reiteration; gemination; rerun; duplicati...
- 頻率 : frequency; rate
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The conventional sphere model of earth and circle model of orbit are discarded, and the ellipsoid model and the ellipse model are selected for further research, which achieves a method to determine the target position through the antenna pointing direction. and the spaceborne sar system design and simulation software is brought forth. this software accomplishes sar system coefficients design for antenna area, pulse repetition frequency, signal bandwidth, downlink data rate, radar transmitter power and satellite platform yaw steering
本文從星載雷達的星地幾何關系入手,舍棄傳統星載合成孔徑雷達研究中的球地球模型和圓軌道模型,研究了在地球橢球模型和橢圓軌道模型下由雷達天線確定目標坐標的方法,並在此基礎上研製了星載合成孔徑雷達系統設計與模擬軟體,完成雷達系統天線尺寸、脈沖重復頻率、信號帶寬、雷達信號數據率、雷達發射功率、衛星平臺的偏航牽引等幾個方面的系統參數設計以及雷達多普勒特性、雷達系統模糊、雷達定位及精度的分析,最後完成雷達回波信號的模擬。The efficient sppc had been performed with 1 - hz - repetition - rate 532nm nanosecond pulses, in which phase conjugate reflectivity as high as 21. 5 % was obtained. when sppc were operated in ce : batio3 with 532nm, 632. 8nm and 790nm cw lasers, the maximum sppc reflectivity of 54. 1 %, 88. 2 % and 80. 5 % were obtained, respectively. unlike the results reported before that four - wave mixing by stimulated photorefractive backscattering ( spb - fwm ) only exists at short wavelengths while four - wave mixing by total internal reflection ( tir - fwm ) only exists at long wavelengths, both of these two mechanisms coexist at all wavelengths from 532nm to 790nm in our experiments
通過大量的實驗全面研究了ce : batio _ 3自泵浦位相共軛特性:在低重復頻率( 1hz ) 、 532nm調q激光泵浦時最高獲得了21 . 5的位相共軛反射率,而此前報道過的建立位相共軛脈沖光最低重復頻率是10hz ;實驗中發現在532nm 790nm波長范圍內,在不同的波長激光泵浦時,同時存在兩種自泵浦位相共軛機制:全內反射?四波混頻( tir - fwm )和受激背向散射?四波混頻( spb - fwm ) ;在連續激光泵浦時,對532nm 、 632 . 8nm和790nm三種波長,最高分別獲得了54 . 1 、 88 . 2和80 . 5的位相共軛反射率;同時還研究了自泵浦位相共軛光的時間穩定性。The future wireless mobile communication systems are expected to provide ubiquitous, high - quality, and high - rate mobile multimedia transmission. however, hostile multipath fading radio conditions give rise to serious inter - symbol interference ( isi ) ; even worse, wireless channel are often time varying, which makes the system more vulnerable and more difficult to track the channel state. orthogonal frequency dvision multiplexing ( ofdm ), which is inherently resistant against isi, has invoked a popular research interest in recent years, and has been a promising candidate technology of the physical layer for future weideband high - date - rate wireless communications. notwithstanding, ofdm is much more vulnerable to errors of both time and frequency synchronization and to that of channel estimation, and how to obtain correct timing and channel estimation efficiently is highly critical to ofdm systems. the dissertation will focus on both of the aspects of ofdm systems mentioned above
但是無線環境的多徑特性造成通信系統中嚴重的符號間干擾,同時無線通道的時變性使得通道特性跟蹤復雜。而正交頻分復用技術( orthogonalfrequencydivisionmultiplexing , ofdm )正是一種解決符號間干擾的有效傳輸手段,因此ofdm技術作為未來寬帶高速率無線通信的物理層候選技術在當前引起了一股研究熱潮。但ofdm系統對定時同步誤差和通道估計誤差非常敏感,如何在ofdm系統中準確快速地實現符號同步和通道估計是至關重要的,本論文將重點針對這兩個問題進行討論。Female courtship signal of the brown planthopper was made of many continuous regular pulses and male ' s signal was made of similar syllabics and had two types with different time domain characteristics. second male vibrational signal differed from male courtship signal with wide spectrum range and regular syllabics frequency. time domain characteristics of signals in different individuals even the same individual were different
頻域特徵分析知,褐飛虱雌蟲求偶嗚聲信號的頻域特性較穩定,個體內比個體間差異小;雄蟲求偶嗚聲信號s 、 e片段頻譜范圍較寬,但主振頻率比較接近,差異不顯著; m片段頻帶較窄,主振頻率mvf略小於s 、 e片段,變異較小; m片段脈沖重復頻率prf為幻This paper ' s study is focused on the principle of bistatic sar on the basis of giving a brief introduction of sar principle, including azimuth resolution, mapping width, focusing deepness, pulse repetition frequency limitation and radar equation etc. then the paper studies the special form of bistatic sar with stationary transmitter
在簡要介紹了合成孔徑雷達的成像原理后,本文著重從原理方面對雙站sar進行了分析,討論雙站sar的方位向解析度,測繪帶寬,聚焦深度,脈沖重復頻率限制,雷達方程等問題,然後對發射機固定的雙站sar這種特殊的雙站sar模式進行分析。Based on apdl, the design language of finite element analysis software ansys, and visual c + +, the software on acoustics design of underwater cylindrical shell structure is developed. when input parameter of the cylindrical shell in the interface redeveloped in this paper, the software execute the batch file of apdl in the vc process to establish the finite element modal and carry out the analysis, the analysis result and the vibration mode can also be displayed. furthermore, the software has been developed to process the acoustics optimization design of the finite cylindrical shell with stiffener in appointed frequency range
本論文從便於工程實際應用出發,對使用有限元分析軟體進行二次開發以方便結構振動分析及改進結構設計的方法和過程進行了研究,在此基礎上對水下航行器圓柱殼體的結構聲學特性進行了分析,在指定頻率區間,對結構以振動輻射聲功率級為目標函數進行了部分參數的結構優化設計,與此同時,為了方便有限元分析軟體的使用和簡化設計過程中大量重復的工作,利用ansys提供的參數化設計語言apdl ( ansysparametricdesignlanguage )結合vc對有限元軟體ansys進行了二次開發,形成了一體化的水下圓柱殼體結構聲學設計軟體。The self - q - switched pulses of high erbium - doped fabry - perot cavity fiber laser are observed and theoretically analyzed. ( 2 ). utilizing the non - linearity characteristics of single mode fiber - back stimulated brillouin scattering ( bsbs ) and the wavelength - selecting characteristics of fiber gratings, self - q - switched pulses are achieved from a linear cavity erbium - doped fiber laser pumping by a 980nm ld continue wave ( cw ) pumping, the pulse width is 2. 2ns and the repetition frequency of pulses is 64. 5mhz
( 2 )利用單模光纖的非線性效應背向受激布里淵散射( bsbs )和光纖光柵的選頻特性,採用980nm半導體激光器連續泵浦方式,在線性腔摻鉺光纖激光器中實現了自調q運轉,獲得脈沖寬度( fwhm )約為2 . 2ns ,重復頻率為64 . 5mhz的穩定的光脈沖輸出。分享友人