osci_transst.asv

电能质量扰动信号

%震荡暂态（oscillatory transients）的ST变换
clc;clear;
%震荡暂态oscillatory transients信号
t=0:300;
w0=100*pi;
t1=64;t2=128;%暂态时间2个T
y1=stepfun(t,t1);y2=stepfun(t,t2);
y3=y1-y2;

A=0.777;c=8.234;a=14.555;
data=sin(w0*0.000625*t)+A*exp(-c*(t*0.000625-t1*0.000625)).*sin(a*w0*0.000625*t).*y3;%产生震荡暂态信号
figure(3);subploplot(t,data)
title('振荡暂态')

noise=awgn(data,30,'measured');%产生30dB的高斯白噪声
data_noise=data+noise;%将产生的30dB高斯白噪声迭加到OSCI_TRANS信号中
figure;
%no noise
subplot(2,4,1);plot(t,data);title('震荡暂态 no noise')
[st_matrix,st_time,st_freq]=st(data);%st of the sag signal
subplot(2,4,2);mesh(abs(st_matrix));
subplot(2,4,3);contourf(abs(st_matrix));
%subplot(2,4,2);mesh(st_time,st_freq,abs(st_matrix));
%subplot(2,4,3);contourf(st_time,st_freq,abs(st_matrix));
subplot(2,4,4);plot(st_time,abs(st_matrix));

%add noise 30 dB
subplot(2,4,5);plot(t,data_noise);title('震荡暂态 add noise')
[st_matrix_noise,st_time_noise,st_freq_noise]=st(data_noise);
subplot(2,4,6);mesh(st_time,st_freq,abs(st_matrix_noise));
subplot(2,4,7);contourf(st_time,st_freq,abs(st_matrix_noise));
subplot(2,4,8);plot(st_time,abs(st_matrix_noise));
figure(3);contourf(abs(st_matrix_noise));