信号

At the same time, combining with the actual condition of delivery pipeline of our country and some prevalent leak detection and location methods, this paper raised a method, which is based on wavelet analysis and negative- pressure-wave to detect and locate the leakage. Jobs in the paper are as follows:As affected by gas density, pressure, specific heat and pipe material, the velocity of negative-pressure-wave improved depending on the energy conservation. At one time, taking the affection of velocity of gas flow, the location formula was modified in some degree.When locating the leaks with location formula, the iterative approach algorithm was adopted as a new method to increase the location accuracy level of system.Multi-scale decomposition and reconstruction of wavelet transform is utilized to filter the noise of negative-pressure-wave, which was brought by leakage. With the capacity to detect the signal singularity fast and accurately, wavelet transform was used to catch the break point of pressure signal. The work improved the accuracy of At in location formula, accordingly improved the location accuracy.Wavelet is a suitable tool for signal analysis. The distinct character is that the mother-wavelet is of optional. That means choosing different mother-wavelet will get different analysis result. So we studied how to choose mother-wavelet and its scale for signal singularity detection. The method is to choose a wavelet by regularities of the wavelet and the signal.Finally, a plan, which bases on SCADA system for inspection and detection of natural gas leakage, is proposed in the article.

其中，主要进行了以下几方面的工作：针对泄漏产生的负压波在管道中的传播速度受媒介的密度、压力、比热及材质等因素的影响，而非声波在空气中传播的速度，本文利用能量守恒原理，对其进行了修正；考虑到管内气体流速对压力波速的影响，对原始的负压波定位公式进行了一定程度的改进，并在利用定位公式进行泄漏点定位时采用逐步迭代逼近算法，提高了系统的定位精度；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了降噪处理；并利用小波变换技术对信号奇异点的快速、准确的识别能力，对经上述消噪后的负压波信号进行了奇异点捕捉，精确捕捉的结果提高了定位公式中上下游站点采集到的负压波奇异点的时间差△t的精度，从而进一步提高了定位的精度；考虑到小波变换是一种基波可变的信号分析工具，也就是说，不同的小波基波对信号分析的结果将有很大差别，这势必影响最终的处理结果，因此，我们又对比分析了本课题中小波基及尺度的选择问题，依据规则性系数相似性原理对母小波的选择进行了探索性研究；最后，还提出了基于SCADA的泄漏检测与定位系统的软件开发构想及系统的嵌入方案。

Such characteristic vector can be applied to further signal processing and fault diagnosis of high current LIA.

应用小波变换具有良好的时频局部特性，通过对强流直线感应加速器脉冲信号的去噪声、信号突变点检测以及时间间隔测量等处理，表明小波变换在LIA信号处理中有广泛的应用前景；利用小波包分析的每个节点都代表了对应频带的信号特征的特点，对"神龙一号"快脉冲波形数据进行小波包变换，以各频带信号能量为元素构造特征向量，实现了高维波形数据的特征值提取，达到了数据压缩和降维的目的，为进一步实现LIA故障智能诊断、预测维护提供了一种可行的途径。

The basic information consists of luminance information and chrominance difference signals. During the composition into one signal, the chrominance signals can interfere with the luminance. Therefore, the television technique has to adopt appropriate modulation methods to eliminate the interference between luminance and chrominance signals.

基本信息由亮度信息色差信号组成，由于在合成中，色度信号可能会干扰亮度信号，因此，还要采用适当方法消除色度信号和亮度信号之间的干扰。

Especially, the technology of Automatic Gain Control and signal processing are studied which are key factors working on the performance of the receiver. Based on analyzing the theory of automatic Gain Control, operational amplifiers 0P37 and logarithmic D/Aconverter AD7111A are used to design variable gain amplifiers which can be controlled numerally, A/D convector LTC1405 is Used to test the echo, Complex Programmable Logic device is used for controller, and an arithmetic is designed for automatic Gain Control which is simulated and analyzed in order to test its feasibility.

本文在分析自动增益控制AGC原理的基础上，采用集成运放OP37和数控增益衰减器AD7111A设计可数字控制的可变增益运放模块；采用高速A／D转换器LTC1405作为回波信号检测模块；采用复杂可编程逻辑器件CPLD作为核心控制模块，构成数字自动增益控制电路，并设计粗调和细调步进控制相结合的算法，对回波信号的增益进行精确而快速的调节控制，使回波信号振幅快速稳定在设计指标范围内，利于接收机后续信号处理电路对回波信号作进一步的处理。

When signals under test are 单击此处编辑母版标题样式 weak, in order to realize signals transmission especially for long distance, direct current amplification or modulation and demodulation may be adopted.

传感器输出的电信号一般为较低频率分量(在直流至几十千赫兹之间)，当被测信号比较弱时，为了实现信号的传输尤其是远距离传输，的电信号一般为较低频率分量(在直流至几十千赫兹之间)，当被测信号比较弱时，为了实现信号的传输尤其是远距离传输，可，当被测信号比较弱时以采用直流放大或调制与解调。

The mulitresolution analysis of wavelet can decomposite signal on different Scales.So it has the ability of processing for signal in frequency-band,which is very useful to analysis the details of signal on a given frequency-band,to build up the identification features of signal and to cancel the signal noise.

小波多分辨率分解能够将信号在不同的尺度上展开，因而具有对信号按频带进行处理的能力，这对于分析特定频段上信号的细节，建立表征识别故障信号的特征以及清除信号的干扰与噪声等方面具有十分重要的意义。

In the paper, the theory and methodology of amplitude correction method using average of several points in discrete spectrum, which is suitable for analyzing the dynamic signals of rotating machinery with small varying speed, is proposed and systematically studied.

系统而完整地提出了处理变速机械弱时变响应信号的离散频谱多点平均幅值修正法的理论和方法，严格证明了该方法能精确地计算出平稳信号和频率微弱波动信号的幅值，能近似地计算出幅值和频率均微弱波动的信号的平均幅值，并应用这套理论成功地解释了频率微弱波动信号的幅值谱表现出较严重的"功率泄露"效应的原

The main results that have been accomplished in the paper are listed below: 1. Accumulated lots of experimental data of life-parameter signals with the equipment of detecting the wounded. 2. Provided a method of frequency domain signal integration based on FFT to detect non-contact life-parameter signals. 3. Built up an algorithm of lifeform identification which was based on the time and the frequency domain analysis of life-parameter signals. 4. Developed an application software of life identification for the wounded detecting equipment system S2000?

取得的主要研究结果有：1、用现有的伤员探测实验平台采集了大量生命参数信号，积累了实验数据，为信号处理及信号特征提取研究打下良好的基础；2、提出了基于FFT频域积累的方法进行非接触生命参数信号分析与检测；3、综合时域、频域中生命参数信号特征分析的实验结果，形成生命体识别算法；4、为52000—l型伤员探测装备样第2页第四军医大学硕士学位论文机研制了伤员探测生命体识别软件系统。

According to singular entropy and Percent of contribution to total energy, the de-noising rank is obtained and the signal is reconstructed. The thesis compares reconstruct wave form of different reconstruct rank and the error of original signal and reconstruct signal is contrasted.According to voltage flicker measurement, voltage flicker detection method based on Mathe Matical filtering and Teager Energy Operator is proposed. The multiple MM filter filters out pulse noise and white noise contained in fliker signal, then the filtered signal is tracked accurately and quikly via TEO.

提出了基于数学形态滤波和TEO能量算子的电压闪变快速测量方法，含噪电压闪变信号经过多结构元素复合数学形态滤波后，采用TEO能量算子计算跟踪电压闪变信号的包络，得到的包络信号用Pisarenco谱分析方法获得闪变调制信号的幅值频率等参数，对不同情况下的电压闪变信号进行了仿真验证。

On the plain scan of CT, the appearances of the aneurysmal bone cyst were the various expansile changes. In destruction of bone, the capsular districts and septation can be seen. On MR T1WI and T2WI, we can see the low signal ring of the diseased region borderline, the diseased region bulk was full of fluid which has miscellaneous signals, it can be seen the low or slightly high signal. In the diseased region, the septation which have low signals both on the T1WI and T2WI can be seen.

在CT上动脉瘤样骨囊肿表现为溶骨性骨质破坏，常有不同程度膨胀性改变，骨质破坏区内可见囊状低密度区及骨性分隔，MRI表现为T1WI及T2WI上可见病灶边缘有低信号环，病灶内主体部分充满囊状液体，信号混杂，在T1WI低或中高信号，在T2WI上呈不均匀高信号，病灶内可见T1WI及T2WI上均呈低信号的分隔。

Finally, according to market conditions and market products this article paper analyzes the trends in the development of camera technology, and designs a color night vision camera.

最后根据市场情况和市面上产品的情况分析了摄像机技术的发展趋势，并设计了一款彩色夜视摄像机。

Only person height weeds and the fierce looks stone idles were there.

只有半人深的荒草和龇牙咧嘴的神像。