故障信号

This paper combines with pipeline delivery of our countrys actual conditions and other methods of detection and location. To the leakage characteristic of the fault to the long-distance natural gas pipeline, a method is raised, which is on the basis of wavelet and negative-pressure-wave to detect the leakage and locate. Jobs in this paper are as follows:Multi-resolution decomposition and reconstruction of wavelet transform is utilized to filter the noises, which the leakage brings the noises of negative-pressure-wave. The research is worked in the wavelet and wavelet packet filter. The wavelet transform have a fast and accurate recognition capability to signal singularity. This paper chooses wavelet technology to catch the break point of pressure signal.

本文结合我国管道输送的实际情况和目前现有的各种泄漏检测与定位方法，针对天然气长输管线泄漏故障的特点，提出了基于小波分析和负压波相结合的方法检测泄漏并定位，其中主要进行了以下几个方面的工作：利用小波变换的多分辨率分解和重构技术，对采集到的管道发生泄漏时产生的负压波信号进行降噪处理，并对小波及小波包优化的降噪效果进行对比性研究；利用小波变换技术对信号奇异点的快速、准确的识别能力，捕捉负压波信号的突变点，从而判断是否有泄漏发生。

Based on the analysis of relevance weight among output signals the method constructs the set group of output signals with minimum relevance weight to reduce the loss of fault coverage using grouping compression,and the method needs no auxiliary circuity.

该方法是在分析输出信号之间相关性的基础上，根据给定的MISR阶数构造具有最小相关度的输出信号集合组，以此来减少输出信号分组压缩时的故障覆盖率损失。该方法不需附加任何辅助电路。

A key point in Short Time Fourier Transform is the choice of window function. Although rectangle window is regarded as the first choice because it's featured by integral harmonic to filter signals and by DC component, decaying DC component and frequency shift of signals cause great error to rectangle window STFT. In addition, transient signals contain rich information of faults, but the fixed time window of STFT fail to collect these information.

STFT 算法关键问题之一是窗函数的选择，矩形窗以滤除信号整数次谐波和直流分量的特点自然称为首选窗，但衰减直流分量和信号的频率偏移对矩形窗 STFT 造成了很大误差；其次，暂态信号中含有丰富的故障信息，傅立叶变换固定的频窗忽略了这些特征信息。

We decomposed and reconstructed the tested signal by use of filter basing on wavelets transform. With maximality of the reconstructed signal's model, we can find the start point of the echo pulse and calculate the fault distance accurately.

作者采用目前已经广泛应用在数字信号处理领域的小波分析的方法，设计了基于小波变换的滤波器对所测试的信号进行分解和重构，利用重构信号模的极大性寻找反射脉冲的起始点从而实现对故障的定位。

At the same time, using combination of gear and photoelectric switch for the sensors, the signal conditioning box of National Instruments Corporation and data collecting card as the main devices, the signal collecting of torsional vibration was completed. In addition, a software of the fault monitoring and analysis was developed with Visual C++. The signal real time collecting of torsional vibration and processing were realized.

同时，以齿盘和光电开关组合为传感器，NI的信号调理箱、数据采集卡等为主要器件实现了扭振信号采集；并采用Visual C++编程开发了故障监测与分析软件，实现了对扭振信号的实时采集和处理。

With the help of the multi-resolution analysis, the singular part in the vibrational signal is abstracted to distinguish the periodic signal, so the useful information for fault diagnosis is got.

将小波分析技术应用到车辆变速箱的奇异点检测中，通过多分辨率分析提取振动信号中的奇异信号，将其周期信号分开，为故障诊断提供了有用的信息。

The wavelet packet analysis applied in fault diagnosis system is studied in this thesis. Using simulation fault data, uncalm and time difference vibration signal of sodium pump are decomposed on different levels and frequencies. To picked-up the eigenvectors reflecting different fault of sodium pump with availability, simulation results have shown its satisfaction in the identification.

对小波包分析应用于故障诊断进行了研究，利用仿真出来的故障数据，将快堆钠泵非平稳时变振动信号分解到不同层次和不同频带上，有效地提取出反映钠泵不同故障的特征向量，在识别中得到了满意的结果。

It has perfect localizable characteristic in both time and frequency domain, the charater istic of instantaneous signal could be well reflected, furthermore, an efficient analysis is to be supplied in diagnose the mechanical fault of non-smooth signals.

小波变换是一种日益获得广泛应用的信号分析方法，它在时域和频域同时具有良好的局部化特性，能够很好地反映瞬态信号的特征，为诊断以非稳态信号为特征的机械故障提供了有效的分析手段。

On the basis of realizing the recognition of polygenetic faults, self-adaption zero pole filter model based on wavelets decomposition and variable time base self-adaption process model is suggested.

在实现多源故障识别的基础上，提出了基于小波分解的自适应零极点滤波模型和变时基自适应处理模型，用于提取和分析弱故障振动信号，以确定故障的早期征兆和类型。

The method colligates weighting moving average residual within L time window to detect multi-type sensor fault,and uses neural network technique to online re-construct sensor signal,and achieves the tolerant proportional integral derivative control.

该方法应用加权移动平均残差技术对传感器故障进行检测，并利用神经网络建模技术在线重构故障传感器信号，重组PID控制器反馈回路，实现容错PID控制。通过在三水箱过程设立多种不同类型的传感器故障，进行仿真研究。

However, as the name（read－only memory）implies, CD disks cannot be written onorchanged in any way.

然而，正如其名字所指出的那样，CD盘不能写，也不能用任何方式改变其内容。

Galvanizes steel pallet is mainly export which suits standard packing of European Union, the North America. galvanizes steel pallet is suitable to heavy rack. Pallet surface can design plate type, corrugated and the gap form, satisfies the different requirements.

镀锌钢托盘多用于出口，替代木托盘，免薰蒸，符合欧盟、北美各国对出口货物包装材料的法令要求；喷涂钢托盘适用于重载上货架之用，托盘表面根据需要制作成平板状、波纹状及间隔形式，满足不同的使用要求。