transform discrete fourier 中文意思是什麼
transform discrete fourier
解釋
離散式傅立葉變換-
2. a frequency extrapolation scheme is developed to effectively predict radar cross section using floating genetic algorithm based on the geometrical theory of diffraction ( gtd ) model. the threshold discrete fourier transform ( tdft ) is introduced for the data compression in angle domain
在目標散射中心建模方面，我們將浮點型遺傳演算法（ fga ）應用於實際人工目標的gtd模型參數的抽取，利用所抽取的模型參數完成了雷達散射截面rcs的頻率擴展以及數據壓縮，並利用擴展的數據提高了距離解析度。 -
Then, based on the theory of discrete fourier transform, discrete cosine transform and discrete wavelet transform, two invisible image watermarking schemes in transform domain are proposed, one is circular symmetric spread spectrum digital image watermarking based on chaotic sequences, the other is the hybrid image watermarking based on wavelet decomposition and discrete cosine transform. finally, the good performance of the two algorithms is verified by some common image processing and attack experiments
在分析了dft 、 dct 、 dwt的理論與演算法的基礎上，提出了兩種基於變換域的圖像隱形水印方案? ?基於混沌序列的圓對稱擴頻水印方案和基於小波分解和餘弦變換結合的水印方案，並通過一些常見的圖像處理及攻擊實驗驗證了這兩種演算法生成水印的性能。 -
According to the theory of digital signal processing, discrete fourier transform has selectivity to frequency just as spectrum analyzer
根據數字信號處理理論，離散傅里葉變換（ dft ）演算法對頻率具有選擇性，有相當于頻譜儀的功能。 -
Moreover, the signal processing method of high range resolution based on inverse discrete fourier transform is analyzed. the synthetic high range resolution of the several scatters is simulated
此外，本文還闡述了頻率步進信號的逆傅立葉變換合成距離高分辨的處理方法，並對多散射點目標的合成距離高分辨效果進行了計算機模擬。 -
This method is easy to implement and has no restriction on array geometry and sensor patterns ; three methods for the design of broadband frequency invariant beamformer are proposed, which are the method of resampling signals received by the array, the dft ( discrete fourier transform ) interpolation method and adaptive synthesis method, respectively. examples and performance analyses are given for each method ; a simplified linear constrained minimum variance broadband adaptive algorithm that based on dft interpolation method is presented. compared with conventional broadband adaptive algorithms, the presented method can reduce computation work greatly
提出了一種簡單、易於實現的恆定束寬波束形成器設計方法，該方法對陣形和陣元指向性沒有任何限制；分別提出了基於陣列接收數據重采樣、基於dft插值和自適應綜合的三種具有頻率不變波束圖的寬帶波束形成器設計方法，對于每一種設計方法都給出了一個設計實例並做了性能分析；提出一種基於dft插值的簡化線性約束最小方差寬帶自適應陣列演算法，該方法可以大大降低自適應陣列的運算量。 -
A new data compression technique, called the threshold discrete fourier transform ( tdft ) method, is proposed to efficiently compress the scattered field data from complex targets
提出了閾值dft （ tdft ）演算法用於實現基於雷達目標強散射中心分佈的rcs數據壓縮。 -
Review of linear algebra, applications to networks, structures, and estimation, lagrange multipliers, differential equations of equilibrium, laplace ' s equation and potential flow, boundary - value problems, minimum principles and calculus of variations, fourier series, discrete fourier transform, convolution, applications
線性代數回顧，網路，結構以及估計的應用，拉格朗日乘數，平衡態的微分方程，拉普拉斯方程和勢流，邊值問題，最小值原理和變分法，傅立葉級數，離散傅立葉變換，卷積，應用。 -
Wavelet analysis have many advantages over discrete fourier transform by zoom - in and zoom - out capability. wavelet denoising in multi resolution approximation has been evolved to become very powerful tools for digital picture signal processing
去噪處理已成為研究重點。小波多解析度逼近分析去噪已發展成為圖像處理的一個重要而有效的工具。 -
A modified real signal model of channelized transmitter is presented that employs multiphase filters and discrete fourier transform to maximize computing efficiency, which can mean much in a radio communication system that requires real - time processing
特別提出了改進的實信號通道化發射機數學模型，通過利用多相濾波與離散傅立葉變換，減少信號處理運算量，這對于強調實時運行的無線通信系統有重要意義。 -
As an implementing method of multi - carrier modulation ( mcm ), discrete multi - tone ( dmt ) modulation uses inverse discrete fourier transform ( idft ) vector as its modulating vector, and discrete " fourier transibrm ( dft ) vector as its demodulating vector, and the process of modulating and demodulating can be realized by using their fast calculating method
作為多載波調制的一種實現形式，離散多音頻（ dmt ）調制分別採用逆傅立葉變換矢量和傅立葉變換矢量作為調制矢量和解調矢量，從而調制和解調過程可以利用這兩種變換的快速演算法實現。 -
By studying the discrete fourier transform properties of the band - limited digital signal, the authors introduce alternating projection neural networks into the paper, expand apnn ' s application scope from real field to complex field, and present several important conclusions on apnn. analyzing and discussing network ' s tolerance to noise, convergence rate and the spectral leakage problem of the truncated signal expected to be extrapolated by using these conclusions, the paper presents an extrapolation algorithm for band - limited signals based on alternating projection neural networks. a lot of simulation experiments show that the algorithm is effective. in addition, the algorithm is also effective to spectrum extrapolation. owing to adopting network structure, the algorithm is prone to parallel computation and vlsi design, and consequently can satisfy real time military processing needs
本文通過對頻帶受限數字信號的離散傅立葉變換特性的研究，引進了交替投影神經網路，並將其應用范圍從實數域拓廣到復數域，且給出了在復數域仍然成立的若干結論.運用這些結論，在對網路噪聲抑制、網路收斂速度及待外推信號因截斷而造成頻譜嚴重外泄問題的分析與討論的基礎上，提出了一種基於交替投影神經網路的外推演算法.模擬實驗表明該方法是行之有效的.另外，該演算法對頻譜外推同樣適用；由於它採用全互連神經網路結構，易於并行計算和vlsi實現，從而可滿足軍事上實時處理的需要 -
The fundamental theory for digital lensless fourier transform holography and its applications in 3 - d object reconstruction and optical metrology are presented in this dissertation. ( 1 ) analytical foundation for numerical reconstruction of digital lensless fourier transform holography, namely discrete fourier transform theory, is presented. the basic principle and mathematical model for recording and numerical reconstruction of digital lensless fourier transform hologram is elaborated
主要內容包括： （ 1 ）討論了數字無透鏡傅里葉變換全息術數值重建的數學基礎? ?離散傅里葉變換的基本理論，分析了數字無透鏡傅里葉變換全息圖記錄與再現的基本原理，建立了數字無透鏡傅里葉變換全息圖記錄與再現的數學模型。 -
In this paper, aimed at the problems existed in theoretical analysis and application of ftm, the discrete fourier transform method is applied to analyze the traditional ftm ( tftm ). and computer simulation is applied. the main propose is to solve the problem, such as frequency shifting, selection of carrier frequency big or small and selection of filter window size. considering the feature of double - exposure holographic interferometry, we propose a modified ftm ( mftm )
針對二次曝光數字全息干涉術中ftm存在的理論缺陷和具體應用到二次曝光全息干涉計量中存在的問題，本文從離散傅立葉變換的角度對傳統的傅立葉變換法（ tftm ）進行了理論分析和計算機模擬計算，並重點致力於解決ftm中的移頻問題、載頻大小的選擇以及濾波窗口大小的選擇等關鍵問題，結合二次曝光全息干涉的特點提出了改進的傅立葉變換法（ mftm ） 。 -
The major work implemented in this paper is presented as follows : ( 1 ) an improved discrete fast polar fourier transform algorithm ( called dpft for short ) is proposed which fast and effectively computes the 2d discrete fourier transform in polar coordinate systems
論文的工作主要包括：一、提出一種改進的離散極坐標付立葉變換（ dpft ）的快速演算法，並在此基礎上，提出一種基於dpft的紋理分類演算法。 -
Hence, this paper focuses on fast channel estimation algorithms for ofdm - cdma receivers. we use comb pilots to estimate the channel response, and propose a low - complexity discrete fourier transform based mmse channel estimator
採用梳狀導頻進行通道估計，提出了一種低復雜度、基於離散傅立葉變換的最小均方誤差的信估計演算法。 -
Circular symmetric spread spectrum digital image watermarking using chaotic sequences as the watermark takes advantage of the discrete fourier transform properties and spread - spectrum communication techniques to embed a circular symmetric watermark in the frequency domain. the watermark can be detected without the presence of the original image even when the watermarked image suffers geometrical attacks such as translation, rotation and scaling. experimental results show that the proposed scheme has good transparency and highly good robustness to geometric transformations
基於混沌序列的圓對稱擴頻水印方案是以實值混沌序列作為水印，根據離散傅立葉變換的特性並結合通信上的擴頻技術，將一圓對稱水印嵌入到了圖像的頻域中，且即使圖像遭受了平移、旋轉、縮放等幾何攻擊檢測水印也不需要原圖像。 -
In chapter 3, the paper presents the theory of wigner - ville distribution ( wvd ), pseudo wvd, smoothed pseudo wvd, discrete fourier transform ( dft ), fast fourier transforms ( fft ), and also expatiates on the
第三章將對wvd 、 pwvd 、 spwvd分佈、 dft和fft變換的理論進行說明，並闡述跳頻解跳與數字中頻接收機的解跳原理。 -
The dft ( discrete fourier transform ) method is use to demodulate the gap length of the low finesse fabry - perot sensor. 3. the accuracy of the results of dft algorithm is analyzed
針對實際光強信號在波長域均勻采樣，而在頻率域非均勻采樣的特點，討論了傅立葉變換的變形? ?離散腔長變換（ dgt ）演算法。 -
The discrete fourier transform algorithm can analyze time - domain ' s stationary disturbance signal effectively and confirm the signal ' s distributing in the frequency domain
而離散傅立葉變換則可有效地對穩態擾動進行分析，得出時域穩態信號在頻域中的分佈情況。 -
On frequency resolution of the windowed discrete fourier transform
加窗離散傅里葉變換測頻解析度研究
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