How to calculate a period of a wave when you don't have the equation of the wave

Hi guys,

I have this wave plotted in MATLAB for 10 periods. I only have the time and height arrays. What I would like is to calculate its period but I don't know how. I was thinking of finding all the values of time (X axis) when the height of the wave (Y axis) goes to 0 and then work from there. But one problem is that X is never 0 but only very close to zero except for the initial point height(1). Any help would be welcome! Thank you.

Answer 1

[Kaushik Lakshminarasimhan]

You can use findpeaks to detect the peaks in your wave and then use the spacing between peaks to determine periodicity.

 [~,peaklocs] = findpeaks(wave);
 period = mean(diff(peaklocs)); % peaks may not be exactly periodic, so take mean

This should work unless your wave is very noisy.

[Nicolas Nicolaides]

Thank you very helpful, I actually used this way!

[Jeffrey Ostler]

This is exactly what I needed to find the period. I replaced 'wave' with (position,time) which were column vectors with data I'd imposted from my daq. Thanks so much.