Using Peak Fit software to deconvolute the peak of the Si MAS NMR spectrum, how to establish a function that meets the integrated built-in function (Gauss-Lorentz function) in the User-Defined Functions module, and at the same time limit the ratio of half peak width to high Lorentz ( Peak shapes were constrained as pseudo-voigt using a Lorentzian/Gaussian ratio = 0.5, full width at half heigh ≤3 ppm ), I try to establish the function shown in the following figure. I do not know where it is not perfect. How to defined Y is a problem for me.I hope my colleagues will not hesitate to comment. It would be better if you could give a specific function.