Use findpeaks on specific frequency range

Hello,

I am trying to find the two peaks just under 1Hz in the plot attached. I wasn't sure how to use findpeaks to do this, because it keeps wanting to find the high value curve in the beggining of the plot, and not the pronounced frequencies after.

Could someone please help me extract these frequencies and what commands I would need to Mark these on the graph?

Thank you.

Answer 1

[Adam Danz]

Limit the range of the peak-search by limiting the inputs.

I can't see the x-ticks in your image but this example ignores any data beyond x=1000.

idx = x < 1000; %hz 
[. . .] = findpeaks(y(idx),x(idx),___);