查询词典 spectrum analysis

The article through the analysis of the various processing techniques to voice signal, in use of FFT algorithms and MATLAB language algorithms, uses MATLAB language guide orders generating graphical user interface GUI, achieves achieve real-time repeat, the plus window treatment, Butterworth filter processing and the repeat of processed voice signal and the display of spectrum analysis to voice of signals collection, functions of various window and filter characteristics analysis and display through the menus and controls of interface by the callback function for the operation; Doing them for the purposes of visibleness, audibility, visuality and intuitionistics.

本文通过对语音信号各种处理技术的分析，采用FFT 算法和MATLAB语言算法，运用MATLAB语言的GUIDE命令生成图形用户界面GUI，通过界面菜单和控件的回调函数的编写，实现对采集的语音信号进行实时回放、加窗处理、巴特沃斯滤波处理以及处理后语音的回放和频谱分析及显示，各种窗函数以及滤波函数的特性分析和显示等；达到可视、可听形象直观的目的。形成一套特色化的软件演示系统，操作简单，方便使用，形象直观，可直接用于课堂教学和实验，更一步促进上海大学的多媒体教学改革

This section simply introduces the basic principles of the conventional analysis of time series (mean, variance, standard deviation; covariance and correlation coefficient; autocovariance and autocorrelation coefficient), frequency spectrum analysis and wavelet analysis.

本文简单地介绍了传统时序分析（包括平均值、方差和标准差；协方差和相关因子；自协方差和自相关因子）、频谱分析和小波分析的基本原理。

It also gives the definitions and stochastic properties of pure random process, random walk process and AR(1) autoregressive process, and analyses the simulative data of three typical random processes using wavelet analysis, frequency spectrum analysis and time-correlation analysis. The stochastic properties of time series and the trend component, the time length of time-correlation and the properties of main frequency of these three typical random processes are summarized as the templates for further research.

给出了包括纯随机过程、随机游走过程和 AR(1)自回归过程等在内的基本随机过程的定义和统计特征，并运用小波分析，时间相关和频谱分析对这三种基本随机过程的模拟数据进行分析，归纳出它们在时序上的随机特征、低频信号趋势项特征、时间相关的长短以及主频信号的位置等特点，作为研究 GPS 接收机误差和多路径效应的随机特征的模板。

Damping identification ; Transfer function ; Spectrum analysis ; Discrete spectrum ; Signal processing

阻尼识别；传递函数；频谱分析；离散频谱；信号处理

In order to avoid spectrum error due to energy leakage, the thesis research on identification of parameters of two close frequency components in discrete spectrum analysis, and simulation result shows the validity of the method.

针对由于能量泄漏造成的频谱误差，深入研究了密集频谱的频域参数识别法，从理论上加以推导，并通过仿真证明了该方法的有效性，可以识别1个频率分辨率以内的两临近频率分量。

The application of the digitalized visible spectrum analysis technique enables the observation of the sensitive spectrum of element Co near ultra-violet area.

摘 要 使用可见光谱数字化分析技术解决了无法在近紫外光区观测Co元素灵敏谱线的问题。

Based on a series of signal process and noise source identification techniques, especially the major noise source identification methods, such as expurgation method, sound intensity analysis, spectrum analysis vibro-acoustic correlation analysis and so on, the pass-by noise control of SC7080A and SC6360B are studied in detail. By the roadway and dais experiments, the major noise and radiating parts are identified and some economical controlling methods are made. For the SC7080A, to control the emissing noise from the intake and shell vibration of air cleaner, a intake muffler is installed between the air cleaner and intake valve. Based on the theory of Helmholtz resonator, One three-parallel-connected resonant silencer is designed and trial-manufactured. For the SC6360B, the attenuation performance of exhaust muffler in high frequency region is improved. To reduce the vibration noise of shell part, the structure of oil sump tank, exhaust manifold shield and exhaust manifold shield are analyzed and improved. At the same time, some measures, such as sound absorption, sound insulation, are taken to reduce the noise of engine surface emissivity and a sound shield is designed.

本文首先综述了目前国内外汽车加速噪声控制的现状、主要方法和技术措施，在此基础上，结合SC7080A和SC6350B汽车的车外加速噪声水平及现状，综合运用分别运行法、声强法、频谱分析法、声振相干函数法等现代噪声源识别方法，对SC7080A和SC6360B汽车进行了准确详细的车外加速噪声源识别并提出了经济可行的控制方案，针对SC7080A，主要在空气滤清器和进气阀门之间的进气管道上加装进气消声器，抑制空气滤清器壳体表面和进气口两处的噪声辐射，根据Helmholtz共振腔原理设计了三腔并联旁支型共振消声器，并进行了工程化设计和试制；针对SC6360B，主要改善了排气消声器在高频段的消声性能，对罩壳类零件进行了结构改进，降低了其表面噪声的辐射，并对发动机舱进行了吸声、隔声处理，设计了发动机隔声罩。

By DEMON we can get more and stabler line spectrum information than by LOFAR, which is to make power spectrum analysis of signal directly.

通过包络解调技术可获得轴频等调制信息，这就是常用的DEMON谱分析方法。

The Hilbert amplitude envelope of the stator current includes the low frequency of fault characteristic, thus it can reduce the signal length by resample the Hilbert amplitude envelope of the stator current by downsampling, which can avoid spectrum aliasing. Then it can reduce the computation time of the MUSIC Method for the spectrum analysis to the resampled signals for the given bandwidth. Meanwhile combining continuous subdivision Fourier transform and rotor slot harmonics based slip estimation it can in advance estimate the concrete values of the fault characteristic frequency, and then inquiry purposely the fault feature component information in the stator current spectrum in order to accomplish the broken rotor bar fault with high sensitivity and h reliability, which eliminates adverse effect of issuable false peaks to the fault detection and formed a novel scheme to detect broken rotor bar fault.

定子电流Hilbert幅值包络信号包含了低频的故障特征频率调制信号，故通过对定子电流Hilbert幅值包络信号进行降采样率重采样、减少分析信号长度，可避免低频段频谱混叠，再对减少的重采样数据进行具有超分辨率的MUSIC低频段估计，可大大降低MUSIC算法频谱估计时间；运用连续细化傅里叶变换和转子齿槽谐波转差率估计技术，可预知故障特征频率精确值，从而可有目的地查询故障分量，消除MUSIC虚假波峰对故障检测混淆的影响，大大提高了故障检测的灵敏度和可靠性，以此形成异步电动机转子断条故障检测新方法。

Through visible wavelength and the UV spectrum analysis, the transmittance is found declined as the mass transport and the cosolvent concentration increases and the cut-off wavelength tends to shift to long wavelength.The FTIR spectrum analysis shows that tin dioxide particulates and PMMA has no obvious surface bonding. Therefore, no new absorption peak is found and so do the change shown on the wave shape.

经由可见光及紫外光穿透光谱分析，发现其穿透率随质传温度及氯化锡/甲醇潜溶剂浓度增加而下降，且截止波长有往长波长移动的现象；经红外光光谱分析，析出的二氧化锡颗粒与PMMA并没有明显的界面键结，故并无新的吸收峰出现，波形改变不明显。

Chrysanthemum of 10 thousand birthday is lax to edaphic requirement, with the arenaceous qualitative loam with fecund, good drainage had better.

万寿菊对土壤要求不严，以肥沃。排水良好的砂质壤土为好。

He unstepped the mast and furled the sail and tied it.

他拔下桅杆，把帆卷起，系住。