sir,please help me out to get psd from time domain function

sir,i want to generate psd by using fft from time domain function i.e,from x vs t graph.i have got the values of x vs t values but i am facing problem during conversion for psd and i have already used 1)psd from fft 2) R2015a suggested by starstrider. But,still i am not getting correct graph sir i will send you two files 1)one file of x vs t from which i have got values 2)second file consist of psd vs frequency where my programme has to match that graph...please help me out sir,in order to get psd