fit curve to oscillatory data

I have a set of data (an example is attached) and I want to fit the a specific curve and find a parameter. However, I am so new this this signal processing world and I am confused with the different terms and commands. I have this function for one sinisoida wave where i is sqrt(-1); ω is angualr frequency; t is time and B and c are constatnts where B is not known. I imagine for a wave like what I have attached it should be . Σ comes into play since the signal shape tells that it is a combination of sinosoidal waves otherwise there would be no Σ in the formula.

Anybody can help me doing this in order to find the right fit to the dat to find B ? (my understanding is that it might be where Bj is connected to each wave that can perhaps be found using Fourier series; not sure anyway)

Thanks

Answer 1

[Very Determined]

This code helps solving the problem, However, it needs some modifications and setting treshholds.

https://www.mathworks.com/matlabcentral/fileexchange/40017-fourier-series-of-real-signals