Finding amplitude and frequency of this signal

Currently, I'm having trouble with finding the amplitude and frequency of this signal I have obtained. I had the idea to use the findpeaks function but it seems to be giving me all the minor peaks in the signal which will affect my calculations for the amplitude. As for the frequency, I was also planning to use the diff in peak times to calculate the period but I'm currently facing the same problem as the findpeaks function also detects the minor peaks. Is there a way to omit the minor peaks in the signal such that a more accurate amplitude calculation can be obtained? Sorry I'm new to Matlab and would appreciate any help I can get!

Here is the graph below!

Answer 1

[Andrey Kiselnikov]

You can try the FFT transform, then find the most significant component. https://www.mathworks.com/help/matlab/ref/fft.html

The magnitude of the "quasi-harmonic" signal changes every time moment, maybe you need to evaluate some effective value?

p.s. Do not forget to apply some window function to your signal before transform.