time frequency 中文意思是什麼
time frequency
解釋
時間頻率-
The fractional fourier transform is linear time - frequency transform, and it doesn ’ t have disadvantages of wigner - ville distribution. moreover, the precision of this method is higher, and the performance of antinoise is better
而分數階傅立葉變換是線性時頻變換，所以它不受交叉項的干擾，沒有不模糊區間減半的缺點，而且它的估計精度高、抗噪性能好。 -
Second, this paper analyzes the time - frequency distribution of the clutter from airborne pulse doppler radar ( pdr ). the side - lobe clutter, which is the main factor to influence the pdr, is analyzed and calculated. based on the simulation of typical geometry of the land, we analyze and discuss the side - lobe clutter and concluded that the dft of can be considered as the phase of the coho
並且根據各種典型地貌的近似模擬，從統計特性上和頻率域上對脈沖多卜勒雷達的旁瓣雜波進行了分析討淪，還得出脈沖多卜勒雷達的dft可以近似地看作相參積累，並在程序的編制中利用了這一個結論。 -
On the basis of investigation and research about the technology of reconstruction for ict image up - to - date, this paper is devoted to develop an algorithm for image reconstruction based on wavelet theory. in this paper, time - frequency distribution for spatially varying filter was used to construct convolve - kernel by dwt, to modify convolve - back - projection algorithm
本文在國內外有關ct圖像重建的研究狀況基礎上，根據小波分析理論，利用小波變換在時頻空間的可變性，用dwt變換構造卷積核，對卷積反投影演算法做了改進。 -
A new double time - frequency imaging method is present to improve the imaging quality
提出了雙時頻雷達成像，用於進一少提高成像質量。 -
So it is very meaningful to study their echolocation calls in ecology concentrates in researching time - frequency charaters of the signals
根據調研我們知道，從生態學角度對蝙蝠的叫聲研究多集中在對信號本身的時頻特性研究。 -
The time - frequency curve of stern scatterer is analyzed. furthermore, high quality images are obtained by identifying the regions which are uniform in frequency. chapter 4 exposits the method of optimal time selection for ship isar imaging in detail
本章分析了船尾處特顯點的時頻分佈曲線，並選擇了時頻曲線中頻率近似不變的時間段得到艦船圖像，其成像質量有了較大的提高。 -
The other research purpose is to discover characteristic information and reliable methods of reflecting spinal cord damage. due to typical damage indicators, amplitude and latent period, have bugs such as limited information and weak stabilities, this project recommends applying time - frequency analysis to monitoring spinal cord function. through analysing and comparing typical signal with stft and cwt, it is proved indicators under time - frequency distribution can be better in reflecting signal changes, espcially the wavelet transformation
針對目前ep監測中判定脊髓損傷的指標（波幅和潛伏期）存在信息量相對較小、穩定性較差的缺陷，本課題提出利用時頻分析技術對術中脊髓功能監護進行研究，通過短時傅立葉變換和小波變換分析和比較典型信號的時頻分佈，證明時頻特徵參數能更有效的提取信號的變化信息。 -
It reduces the “ music noise ” using the human auditory characteristics, and enhances the hearing quality using the speech spectrum distribution characteristics in the time - frequency dimension
主要以譜減法為基礎，結合人耳的聽覺特性從而減少殘留「音樂噪聲」的影響;結合語音的語譜在時-頻域分佈特性從而提高增強后語音的聽覺質量。 -
According to the characteristics of the human pronunciation and the speech spectrum distribution in the time - frequency dimension, the paper finds out that there is a shortcoming of the speech enhancement system which is based on the masking properties of human auditory
根據人的發音特點，通過分析語音的語譜在時-頻域的分佈，發現把聽覺掩蔽效應應用於語音增強時存在不足之處。 -
Aiming at five kinds of targets from geneva lake which are rock, sand, pebble, grit and sullage, the features we extracted based on the cwt time - frequency matrix are singular values, some parameters of histogram and invariant moment
針對萊蒙湖底的巖石、沙、卵石、砂礫、淤泥等五類目標，文中所提取的特徵主要有時頻矩陣的奇異值、直方圖的有關參數以及不變矩等三類特徵。 -
Wavelet transform, which has a multi - resolution analytic character, is a time - scale ( time - frequency ) analytic method of information. moreover, as both of its time - window and frequency - window can be changed it processes the ability of expressing local characters of information in time - frequency domain
小波變換是一種信號的時間尺度（時間頻率）分析方法，它具有多解析度分析的特點，而且在時頻兩域都具有表徵信號局部特徵的能力，是一種窗口大小固定不變但其形狀可改變，時間窗和頻率窗都可以改變的時頻局部化分析方法。 -
We illustrate the wavelet package analysis that can obtain the time - frequency distribution figure of noise signal, which can be used to define gray - image. through image - average, we can get the standard time - frequency distribution images of different main bearing gap. based on that, a main bearing wear fault diagnosis model using image matching is set up
然後對圖像進行平均，得到主軸承在不同間隙狀態下的「標準」時頻分布圖，建立了柴油機主軸承間隙圖像匹配的故障診斷模型，匹配時所用的參數為兩幅圖像之間的歐氏距離。 -
Chapter 1 introduces the extensive application of hf / vhf communication and hf / vhf radios in military field, and points out the significance for promoting the research work of fh communication countermeasure using modern signal processing techniques, especially time - frequency analysis
第一章介紹了短波通信和短波跳頻電臺在軍事領域中的廣泛應用，以及現代信號處理技術特別是時頻分析技術對促進跳頻通信對抗研究的重要意義。 -
The reassigned smoothed pseudo wigner - ville distribution ( rspwvd ) is introduced, which has less interference and higher resolution than other time frequency distributions like wigner - ville, choi - williams etc. it is used to detect the multi - knocking of engine such as cylinder, piston pin, valve, crank bearing, connecting rod bearing and jib knocking. a new fault diagnosis technique based on the rspwvd for the engine multi - knocking problem is proposed. by comparing the bispectrum and bicoherence of the gear vibration signals, it is demonstrated that bispectrum has an advantage over bicoherence for feature extraction of such signals
第四章首次引入一種重分配方法，得到干擾項少而解析度高的重分配平滑偽魏格納維爾分佈（ rspwvd ） ；對發動機曲軸主軸承響、連桿軸承響、活塞銷響、活塞敲缸響、氣門響和挺桿響等常見機械異響故障振動信號特徵進行了全面地比較分析；通過對各種異響故障特徵信號的分析研究，提出基於rspwvd的發動機多異響故障診斷策略，利用該策略可以準確識別不同的發動機異響故障。 -
The signal process function of the software include these function : digital filter, windowing, auto - correlation function and cross - correlation function, mean and variance, probability density function and probability distribution function statistic ; auto - power spectrum, cross - power spectrum, frequency response function, coherence function, cepstrum analysis based on fft ( fast fourier transfer ) ; joint time - frequency analysis based on stft ( short - time fourier transfer )
軟體的處理功能包括：數字濾波、時域加窗、自相關與互相關處理、均值和方差計算、概率密度和概率分佈函數計算；在快速傅立葉變換（ fft ）基礎上計算自功率譜、互功率譜、頻率響應函數、相干函數、倒頻譜分析；基於短時傅立葉變換（ stft ）的聯合時頻分析等。 -
Including irrigation time, frequency, and quantity of water, of which based on the evapotranspiration rate and crop coefficients in different months and the rank of visual appearance of different date
根據草坪質量與土壤含水量、土壤水勢的相關性及作物系數、蒸發量等參數，準確計量其灌水時間、灌水量和灌水頻率。 -
In this thesis, the theories of joint time frequency analysis and image processing are combined, and a new fbp method called stf is proposed. the characteristics of digital and application are investigated for stf
本文根據顫振試驗的原理和觀測信號特點，綜合運用聯合時頻分析和圖像邊緣識別理論，提出了一種顫振邊界預測的新概念? ?時頻共振（ stf ） ，並完成了stf方法和演算法的研究。 -
Wavelet analysis is a tool of time - frequency analysis after fourier analysis
小波分析是繼fourier分析之後的新的時頻域分析工具。 -
In this paper. we first introduce the basic concept of time - frequency analysis, include short - time fourier analysis
本文首先介紹了時頻發展的基本概念和比較成熟的時頻分析方法? ?短時fourier分析。 -
The fh signal is a kind of non - stationary signal that the frequency changes non - linearly along with the time. however, the time - frequency analysis technique is the powerful tool to deal with these signals
跳頻信號是一種頻率隨時間非線性變化的非平穩信號，而時-頻分析是分析這類信號的有力工具。
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