How to apply Hilbert Huang transfer method on the signal Sc(t):

How to run Hilbert spectrum of the following function(signal):

Answer 1

[Ayush Bansal]

Create a t vector varying from 0 to 0.3s with sampling rate fs

t=[0:1/fs:0.3];

[value,idx1]=min(abs(t-0.1)); which will give index for ta

Similarly find index for tb and tc.

Create a signal vector of size t;

Signal=zeros(length(t));

Then define signal for 0-ta,ta-tb and tb-tc.

Use emd(x) to find intrinsic mode function.

Use hht(imf) to find Hilbert spectrum where imf is intrinsic mode function.

[Jan Ali]

Thanks a lot Ayush, as I am new with Matlab would you please write the script for the function given above?

[Jan Ali]

Hi Ayush,

This pice of code: [value,idx1]=min(abs(t-0.1)); is difficult for me to realize.

Also I don't know how to generate a signal in this style. However, I have created my own signal but I don't get the result as expected:

fs=2000;

t = 0:0.0001:0.3; % defining time axis

ut1=t>=0; % unitsetp1 takes 1 only when t is greater than equal to 0

ut2=t>=0.1; % unitsetp2 takes 1 only when t is greater than equal to 0.1

ut3=t>=0.18;% unitsetp3 takes 1 only when t is greater than equal to 0.18

ut4=t>=0.3; % unitsetp4 takes 1 only when t is greater than equal to 0.3

t1=ut1-ut2; % t1 takes 1 only when 0<=t<0.1

t2=ut2-ut3; % t2 takes 1 only when 0.1<=t<0.18

t3=ut3-ut4; % t2 takes 1 only when 0.18<=t<0.3

s1=sin(2*pi*50*t)+0.2*sin(2*pi*250*t);

s2=sin(2*pi*50*t)+0.2*sin(2*pi*250*t)+sin(2*pi*500*t).*exp(-30*t-0.1);

% s2=sin(2*pi*50*t)+0.2*sin(2*pi*250*t)+sin(2*pi*500*t).*exp(-30*t2-0.1)+0.7*rand(size(t2));

s3=sin(2*pi*50*t)+0.2*sin(2*pi*250*t);

s = s1.*t1 + s2.*t2 + s3.*t3;

plot(t,s);

I would highly appreciate if you could help me where I am wrong and how to acheive the true result.

Thanks in advance,