echo frequency 中文意思是什麼
echo frequency
解釋
回波頻率-
Based on the analysis of the beat frequency signal, the expression of the beat frequency phase is deduced. the expression indicates physics meanings of quantities to be detected and supplies theoretical bases for detection methods. by using two - dimensional fft, the range and velocity information of target is got out from the echo. according to the periodicity range ambiguity of symmetrical pulses in fmpcw, the processing method of sliding time window is used
通過對差頻信號進行的分析，得出了差頻相位的具體表達式，表現出了要檢測的各量的物理意義，對檢測的方法提供了理論依據。利用二維fft方法，可以有效地提取回波中目標的距離與速度信息。對于fmpcw信號由於均勻脈沖產生的周期性距離模糊的問題，採取時間波門的處理方法。 -
High frequency ground wave radar for near ocean inspection and ocean remote sensor is a method that use ocean echo wave dopier spectrum to deduce the parameters of ocean situation
高頻地波雷達近海監測和海態遙感技術是一種利用海洋回波多普勒譜反演海態參數的方法。 -
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。 -
Section ii describes the design approach and implementation of speech module on mcf5249 coldfire core. the speech codec optimizes g. 729a codes and added voice activity detection of g. 729b to save bandwidth ; the implementation of acoustic echo cancellation uses nlms algorithm and it can reduce echo though designing adaptive fir filter and speech detector ; the dtmf and cpt generate signal using two second order digital sinusoidal oscillators and detect signal by picking up the frequency information. but only get the frequency information is not enough in cpt detector, this thesis introduces a method
其中對語音編解碼器的設計採用優化g . 729a代碼達到設計要求，並在此基礎上加入g . 729b的靜音檢測模塊，以進一步降低網路傳輸帶寬;對回聲消除器的設計採用nlms演算法，通過設計自適應fir濾波器和語音檢測器達到回聲消除目的;對雙音多頻設計，信號發生端採用構造靜態參數表並通過二階正弦振蕩器產生信號，信號檢測端提取頻率信息以檢測信號;對呼叫進程音設計，除了類似雙音多頻的信號發生及頻率檢測設計外，還需要檢測信號持續時間，作者設計了一種基於匹配狀態表的方法以檢測信號持續時間。 -
From the result we get the following conclusion : for narrow - band signal, the effect of the method based on fft is best. for wide - band signal, when snr is up to certain degree ( higher than - 7db or so ), the curves of square error of modified methods are more obvious and closer to crb. for an echo composed of more than one frequency or direction, space - frequency distribution could show more direct information of frequency and direction, which is more advantaged to make precise judge and estimation for doa of echo
從估計結果發現，對于窄帶回波信號，基於fft的方法估計性能大大優于其他方法；對于寬帶回波信號，在信噪比達到一定程度（高於約- 7db ）時，補償后的幾種估計法的性能改善均比較明顯，誤差曲線越來越接近crb曲線；對于回波中存在多頻率多方位的情況，空間?頻率分布圖能提供較為直觀的頻率及方位信息，因此應用空間?頻率估計法來進行方位估計，更有利於進一步對回波的具體方位進行準確判斷和估計。 -
Design of special processor for wireless fuse solid target video frequency echo simulator based on fpga
引信體目標視頻回波模擬器專用處理器設計 -
Through utilizing the shift multiplication characteristics of m series, this kind of radar system eliminates the bad effect of doppler frequency. in theory, the doppler tolerance of the radar system can reach the half of the code rate with proposed echo pretreatment method in this paper
從理論上說，應用於該雷達系統的信號處理方法可以使得雷達系統的多普勒容限達到偽碼子碼重復頻率的一半，從而使偽碼調相雷達可以有效地發現高速目標。 -
The radar which is embedded on platform sidelooking, but the platform will be disturbed by airflow inevitably. so, the radar will have a small sloping angle, thereby, the doppler centroid that is not zero and doppler frequency rate need to be estimated from the raw echo data in order to focus in azimuth commendably
場景成像的合成孔徑雷達一般是正側視放置，但是載機不可避免的要受到各種擾動影響，雷達會有一定的斜視角，從而導致了多普勒中心頻率不為零，多普勒調頻斜率也隨著雷達斜視角改變。 -
This thesis discusses the pulse doppler ( pd ) weather radar signal processing system including digital intermediate frequency ( if ) receiver, especially on the application of if sampling and digital demodulation technique in pd weather radar signal processing system, the influence of amplitude and phase unbalances of in - phase and quadrature channels on weather radar echo spectrum estimation, ground clutters elimination algorithms and a typical engineering realization scheme of pd weather radar signal processing system
本論文研究的是採用數字中頻接收技術的脈沖多普勒氣象雷達信號處理系統，重點研究了中頻采樣及數字解調技術在脈沖多普勒氣象雷達信號處理系統中的應用、正交雙通道幅相不平衡對氣象回波譜估計的影響、地雜波濾波演算法，以及脈沖多普勒氣象雷達信號處理系統的具體工程實現。 -
The " simple " method based on cwt is inducted to underwater signal processing to estimate the instantaneous frequency of echo. in essential, this method is to extract the wavelet ridge from the maximum of continuous wavelet transform, according to the corresponding relationship between wavelet ridge and signal frequency, finally to obtain the estimated instantaneous frequency
文中將基於連續小波變換的『 simple 』方法引入到水下信號的瞬時頻率估計中來，也即通過尋求連續小波變換幅值的最大值來得到小波脊，再根據小波脊與信號頻率之間的對應關系，最終完成信號的瞬時頻率估計。 -
The computer simulations show the validity of the models. 3. joint estimation of the time delay and doppler frequency based on short - time fourier transform ( stft ) and time - frequency analysis are studied to estimate the parameters of the underwater target echo
針對主動回波信號參量的估計問題，重點研究了利用短時傅立葉變換、時頻分析進行時延和多普勒頻移聯合估計，進而進行目標距離和速度參數的估計。 -
Firstly, we introduce the radar equation of weather radar, the basic principles of detection weather targets, the time and frequency domain properties of weather radar echo and its simulation methods
首先簡要介紹了氣象雷達的雷達方程、氣象雷達探測氣象目標的基本原理、氣象目標回波的時域頻域特性和氣象回波信號的模擬方法。 -
Lfmcw echo is modulated by doppler frequency. according to the characteristic, moving targets with different ambiguous velocities could be classified via mtd, but the range - velocity coupling problem still exists
線性調頻連續波雷達回波同脈沖雷達一樣受到了多普勒頻率的調制，通過動目標檢測（ mtd ）可抑制雜波，檢測運動目標。 -
1. stepped - frequency signals are used in echo simulation. it could generate synthetic high resolution image
1 、用步進頻率信號完成回波模擬，研究了這種信號的特點。 -
For those biological signals like echo of bat or whale, as well as man - made system signals like radar or sonar signal, the instantaneous frequency of signal component contains important information and could be used for signal model parameters extraction. so that the proper choose of transformed domain and signal characteristic extraction method is of crucial important. the ridge extraction method used for signal characterization was first proposed in the 1990s, it ' s based on the study of the phase of the wavelet ( or other linear ) transform
對于許多實際的信號，如蝙蝠發出的超聲波、鯨魚的叫聲等生物信號，以及雷達、聲吶等人造系統產生的信號而言，信號瞬時頻率的變化規律反映了信號重要的特徵，並且也是信號模型中關鍵的參數，因此選擇合適的變換域提取信號的瞬時頻率信息，並選擇合適的方法對信號進行重建是很重要的問題。 -
B ) in isar imaging of moving targets with high speed and acceleration, the echo signal is decomposed by emd, which is used to remove the high frequency component induced by high speed or acceleration
2 、針對高速和加速度並存的機動目標，通過對回波信號的emd分解，去除由於高速和加速度產生的高頻成分，用優化后的余量進行isar成像。 -
( 2 ) based on the mode of ultrasonic echo, this paper designs a frequency - dependent compensation filter to compensate the absorbed attenuation when the ultrasound transmits in a tissue
（ 2 ）在建立超聲回波信號的數學模型的基礎上，設計了頻率補償濾波器。 -
Within one single source echo, both doa and time - delay can be estimated simultaneously by this algorithm via high - resolution rotational invariance technique and high - resolution time - delay frequency ( tdf ) technique. the esprit - tdf algorithm has features of low computation, good precision, and high resolution both in doa and time - delay. it is suitable for multiple source exact localization
該方法利用高分辨旋轉不變技術和高分辨時延頻率技術，可在單次目標回波內實現多目標信號的方位和時延參數的高分辨聯合估計，具有運算量小、分辨能力強、估計精度高等特點，能夠對多目標進行高分辨精確定位。 -
In this thesis, we mainly discuss the signal detecting of radar echo and the techniques to process them. we labored on pulse integration, correlation detectingand wavelet techniques and their applications in radar area. three types pulse integration are introduced i. e video integration, binary integration and frequency domain intrgration
論文主要詳細論訴了信號積累技術，相關檢測技術以及以小波變換這三種技術在雷達信號檢測和處理中的應用，在信號積累技術中，詳細討論了視頻累積，二進制累積技術的基本原理和實際應用。 -
Based on the analysis of echo signal and ambiguity function of lfmcw radar, this dissertation advances new theories of lfmcw radar signal detection and estimation and eliminates range - velocity coupling using mtd - frequency domain pairing
在對lfmcw雷達回波信號和lfmcw雷達模糊函數進行分析的基礎上，提出了lfmcw雷達目標檢測與參數估計方法，並利用mtd -頻域配對法消除lfmcw雷達距離-速度耦合。
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