Finding maximum and minimum

Hi, I have a question regarding how to find all the maximums on the following graph, because it is not just one. It represents an earthquake shaking a building and the acceleration decreases by a certain amount of damping.

The time interval is not identical.

Answer 1

[Stephen23]

If you have the Signal Processing Toolbox then you can use findpeaks. To find the minima simply invert the data.

Otherwise search for "peaks" or "peak finder" on MATLAB File Exchange:

https://www.mathworks.com/matlabcentral/fileexchange/?term=peaks

You might also be like to have a look at envelope fitting tools.

[Tsvetan Donov]

So I have named the x axis- Time and the y axis- Struc. I write: plot(Time, Struc) - this gives me the graph Then how do I use the findpeaks function?

Thanks!

[Stephen23]

@Tsvetan Donov: You should start by reading the findpeaks documentation. Why else do you think I gave you that link? The documentation explains what syntax is allowed, and has examples for you to try out! Probably you can simply call:

[pksMax,locsMax] = findpeaks(data)  % maxima
[pksMin,locsMin] = findpeaks(-data) % minima