用于虚构仪器的频率测量软件系统设计

Foreword 　 inside ballistic radar is measured fast in, the rate that wants the pill that finish is measured, measure fast principle according to Duopule, need undertakes the estimation of frequency measures Duopule, and frequency estimation also is the classic problem in signal parameter estimation. Had offerred many meanses domestic and internationally at present, basically have way of the one frequency domain when time domain law, chart reckons the method is mixed, among them law of cycle of main know exactly about sth has mixed time domain law 0 detect law two kinds, its are main defect is measure precision low; and when law of one frequency domain basically has short when accept of Fourier commutation, Wei Ge one dimension Er distributings etc, but computational volume is average bigger, finish real time processing hard. In addition, as the development of fictitious instrument, yu Jiliang of have the aid of's good man-machine interface and powerful signal handle a function, undertake the form that treats platform builds signal to also make trend of a kind of development increasingly. Go up from essence for, fictitious instrument is the result that instrument science and technology and deep administrative levels of computer science and technology combine, it emphasizes the concept that " software is instrument " , operation door can define instrument function according to his need, establish the test system that oneself want better. It is the processing according to signal and collect (ADC) , the analysis of data and processing (the output of DSP) , result (DAC) and indication structural pattern will build general signal to handle platform of strong put oneself in another's position, in this general signal handles platform of strong put oneself in another's position, the instrument that called different test software to form different function [1] . With hereat, the article uses fictitious instrument platform, combinative power chart estimates the assorted measurement technique that measures with frequency, undertook signal frequency measures systematic design. 　 of of 1 frequency measurement technique normally, because the spectrum of useful signal and noise is characteristic different, because this power chart estimates a method,become a kind to collect useful signal below noise setting (like sine signal) effective method. In view of this, in Duopule frequency is measured in, can have collection data power chart is analysed first, next the method that repass frequency domain measures frequency will finish what much general straps frequency to beg take. Can divide in power chart analysis to be classical music estimation and contemporary music estimate, the typical delegate of method of classical music estimation has the; such as periodic plan law, Welch law and the typical delegate of method of contemporary music estimation has law of the magic art of music of law of model of law of model of AR model law, MA, ARMA, entropy, biggest likelihood and feature to decompose a law to wait. Frequency domain measures frequency method to basically peak of energy focus law, chart searchs a law to wait, measure the combination of frequency method through choosing different power chart to analyse method and frequency domain, all can achieve the goal that measures signal frequency. 　 of estimation of chart of 1.1 Welch power estimates in classical power chart towel, the chart function that uses estimation of law of direct and periodic plan to go out often bad, main show is in of chart rise and fall bigger, variance is bigger. Use Welch law to be able to improve law of direct and periodic plan to reckon the variance that gives a fair amount of confidence is characteristic. Its basic idea is the method that uses section to add a window divide one length into L for the data XN(n) of N paragraph, every paragraphs of length is M, promise every paragraphs of data to have partial jackknife, beg a) of each paragraphs ω of power chart Pi(respectively, try next average, get average the power after chart, namely: 　 basis probability statistic theory is knowable: Using Welch law to estimate the variance of the power a fair amount of confidence that give is the 1/L of the variance that estimates a fair amount of confidence that give directly roughly, and section is more, variance is smaller, but frequency resolution is lower also, deviation greatens. So, the chooses L and M value with the proper requirement that wants variance of give attention to two or morethings and resolution in be operated actually [2] . The principle that chart of rate of business of law of model of AR of 　 of 　 of estimation of chart of law of 1.2 AR model estimates is: The signal X(n) that assumes place is analysed is the white noise ω that is 　 by error of a mean square (N) incentive linear moves fixed system H(x)(namely AR model) earning arrives, the power chart estimation that analyses signal is: In type: To input the variance of alignment, n1, A2... , Ap is the parameter that wait for appraise [3-4] . 2 frequency measure a system to design 　 　 after the design 　 of the face plate before 2.1 fictitious instruments starts LabVIEW, the choice opens the option of a new face plate, the control object that operates C0ntrols pattern plate to go up next (Controls) and indication object (Indications) founds a graph to change user interface (namely in front board) [5] . The system is surveyed in frequency in the design, according to afore-mentioned frequency measurement technique, face plate basically includes signal to produce chart of module, power to reckon module, frequency measures module and result to show module before 4 parts, if the graph is shown 1 times,its interface is designed. On one page 12 below one page

　　引 言

　　在内弹道雷达测速中，要实现弹丸的速度测量，按照多普勒测速事理，需要进行多普勒频率的估量测量，而频率估量也是信号参数估量中的经典问题。今朝国内外已经提出了不少办法，首要有时域法、谱估量办法和时一频域法，其中时域法首要稀有周期法和过零检测法两种，其首要错误真理为测量精度低;而时一频域法首要有短时傅里叶变换、魏格纳一维尔漫衍等，但计较劲一般较大，难以实现实时措置。

　　此外，跟着虚构仪器的成长，借助于其精采的人机界面和强大的信号措置性能，进行信号措置平台的构建也日益成为一种成长趋向。从本质上来说，虚构仪器是仪器科技与计较机科技深条理连系的产物，它强调"软件就是仪器"的概念，操作户能够按照本身的需要界说仪器性能，更好地组建本身所需的测试系统。它是按照信号的措置与采集(ADC)，数据的分析与措置(DSP)、成果的输出(DAC)及显示的结构模式来设立通用信号措置硬体平台，在这个通用信号措置硬体平台上，挪用分歧的测试软件就组成了分歧性能的仪器[1]。用于此，本文操纵虚构仪器平台，连系功率谱估量和频率测量的组合测量办法，进行了信号频率测量系统的设计。

　　1频率测量办法

　　凡是，因为有效信号与噪声的频谱特征分歧，是以功率谱估量办法成为一种在噪声背景下提取有效信号(如正弦信号)的有效办法。鉴于此，在多普勒频率测量中，能够将采集的数据前进前辈行功率谱分析，而后再经由过程频域测频的办法来实现多普勒频率的求取。在功率谱分析中可分为为经典谱估量和现代谱估量，经典谱估量办法的典型代表有周期图法、Welch法等;而现代谱估量办法的典型代表有AR模子法、MA模子法、ARMA模子法、熵谱法、最大似然法和特征分化法等。频域测频办法首要有能量重心法、谱峰搜索法等，经由过程拔取分歧的功率谱分析办法和频域测频办法的组合，均可达到测量信号频率的目标。

　　1.1 Welch功率谱估量

　　在经典功率谱估量巾，采用间接周期图法估量出的谱性能经常欠好，首要表示在谱的坎坷比较大，方差比较大。采用Welch法能够改善间接周期图法估量出谱的方差特征。它的根基思惟是采用分段加窗的办法把一长度为N的数据XN(n)分成L段，每段长度为M，并答应每段数据有部门重叠，分袂求出每一段的功率谱Pi(ω)，而后加以平均，获得平均后的功率谱


　

　　按照概率统计理论可知：操纵Welch法估量出的功率谱的方差大致是间接估量出的谱的方差的1/L，而且分段越多，方差越小，可是频率分辨率也越低，误差变大。所以，在理论操作中要兼顾方差和分辨率的要求恰当的拔取L和M的值[2]。

　　1.2 AR模子法谱估量

　　AR模子法做功率谱估量的事理是：假定所分析的信号x(n)是由一个均方误差为

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发布日期：2009-1-1　【返回】