How to measure any disturbance in a signal that is exceeding a threshold?

Hi,

Assuming having a noisy signal as attached, I'm interested in measuring any disturbance that exceeds a threshold, i.e., 0.12. How can I do that?

Thanks in advance!

[Walter Roberson]

Is that 0.12 an absolute value, or is it a relative value? If it is relative, what is it relative to?

[Susan]

@Walter Roberson Thanks for your response.The 0.12 is an absolute of the disturbance peak-to-peak value.

Answer 1

[Walter Roberson]

wherebig = find(Yvf > 0.12);

[Walter Roberson]

But see also findpeaks with 'MinPeakProminence',0.12

[Susan]

@Walter Roberson Thanks for your response. How should I calculate that if 0.12 is the value of the disturbance peak-to-peak?

[Walter Roberson]

[~,LOCS] = findpeaks(Yvf, 'MinPeakHeight', 0.12);

Note that the find() done earlier would locate all of the entries in Yvf > 0.12, whereas findpeaks() with this option would look for locally high points

[Walter Roberson]

Which one you would use (or which options for findpeaks()) would depend on whether you need to know the immediate start of the disturbance crossing a threshold, or if you want instead to know where the peak of the disturbance was.