峰值法模态参数识别

%峰值法 clear close all format long fprintf('Samples In Test :\n'); path_base = sprintf('test'); dir_sample = dir(path_base); [nsample,dummy] = size(dir_sample); nsample = nsample - 2; for i =1:nsample fprintf(strcat(num2str(i),': ')); fprintf(dir_sample(i+2).name); fprintf('\n'); end SampleNum = input('Please select the sample number:\n'); path_sample = strcat(path_base,'\',dir_sample(SampleNum+2).name); %strcat：连接字符串的函数 name_sample = dir_sample(SampleNum+2).name; %提取测试数据 data(:,1)=load(path_sample); %所选的时域样本内数据个数 ntdata = length(data(:,1)); Cvtdata= zeros(ntdata,1); %【1】正常信号处理: Cvtdata = data; %【1】正常信号处理end; % %【2】Narada信号转换: % for j=1:length(data(:,1)) % data(j,1) = data(j,1) * 5.0 / 65535.0; %Convert the data 转化为电压信号 % end % % %增益系数 % gain = 10; % for j=1:ntdata % Cvtdata(j,1)= data(j,1)/(gain*200/1000); % end % Avgdata = zeros(1,1); % Avgdata = mean( Cvtdata(:,1) ); %求数据平均值 % %【2】Narada信号转换end; % 峰值法识别 f = 800; %采样频率 fs = f; fc = 0.02; %高通截断频率 % dummyV = IdealHighPass (DSet, fs, fc) ; %滤波 % nDSet= dummyV(1:size(DSet,1)); t = 0:1/f:(ntdata-1)/f; %%% FFT 快速傅里叶变换 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% % [Ns,dummy]= size(nDSet(:,1)); %Sample size 样本大小 mag=abs(fft(Cvtdata,ntdata)); %Magnitude mag(1:5,1)= mag(1:5,1)/20; freqdomain= fs*(0:ntdata-1)'/ntdata; % Frequency series figure; plot(t,Cvtdata); xlabel(['Time (s)']); ylabel(['Accel (g)']); grid on % annotation('textbox',[0.2,0.8,0.9,0.2],'string',strcat( Narada_name,' Time: ',dataFolder),'EdgeColor','none','FontSize',16); figure; hold on title('fft-data'); plot(freqdomain(1:ntdata/2,1),mag(1:ntdata/2,1)); xlabel('Frequency (Hz)','FontSize',14); % ylabel('Magnitude','FontSize',14); ylabel('Magnitude','FontSize',14); hold off %%%Obtain psd estimate using welch's method if 1==1 figure; % hold on title('pwelch-data'); [psd_c,f_c]=pwelch(Cvtdata,ntdata,0,[],fs,'onesided'); %pls set the stablized time of zeropadding as 10s. pwelch(Cvtdata,ntdata,0,[],fs,'onesided'); figure; loglog(f_c,psd_c); xlabel('Frequency (Hz)'); ylabel('Power Spectrum Density '); % hold off end