similarity between closely related signals

Hello Community,

I have two signals taken over same time samples. (acti.mat & phs0.mat)

how do i find out the time instant till which both signals are closely same (quantatively very close and shape similar).

like for example visually i can find that till 21.2ns the signals are similar

 figure
>> plot(acti(:,1),acti(:,2))
>> hold on
>> plot(phs0(:,1),phs0(:,2))

How can i find this time instant directly ?

I do not know the excat use of corrcoef or xcorr here.

Answer 1

[Net Fre]

You can create a vector calculating the difference between the two, and then find the first index where it is larger than a specific threshold:

MyDifference = abs(acti(:,2)-phs0(:,2)); % calculate the absolute error between corresponding elements.
MyThreshold = 1; % or whatever number you want.
find(Mydifference>=Mythreshold,1) %find first difference that is bigger than MyThreshold

Theoretically you could use:

find(Mydifference~=0,1)

But in your attachments the values aren't exactly zero so you would need to determine what difference is to big for you.

[Sajid Afaque]

I have a window(signal for a particular duration), say part of phs0.mat how do I find this part in acti.mat , the best fit region in acti.mat