how can I force one parameter in 2 fitted function to be the same?

Hello everyone,

I have 2 data sets and I have fitted them to fourier series using the fit function.

the problem is there omega (w) is not the same . The w values are almost the same (0.07842 and 0.07827) but they should be exactly the same

I don't want to tell matlab the values , but I want to force it fit both data sets with the same w.

how to i do that?

Tnx.