How do I fit a Sinuscurve to my Data-Function, WITHOUT Cftool?

C = dlmread('Spektra_Spektrometer2_p.txt.','\t','A3..B652');  

 x1= C(:,1);
 y1= C(:,2);
[fitresult,gof]= sinFit(x1,y1);

i am Missing this. How do I get those numbers that define the Sinusfit

spek2 = dlmread('Spektra_Spektrometer2_p.txt','\t','A3..B652');
x1 = spek2(:,1);
y1 = spek2(:,2);
[fitresult,gof]= sinFit(x1,y1);              
phi = -348.3;                    %how do i get this??
yfit = -0.28*sin(0.016*x1+phi)+1.284;    %how to i get this??

Answer 1

[Star Strider]

See if the approach in Curve fitting to a sinusoidal function will do what you want. It uses only core MATLAB functions, no toolboxes.