I want to calculate the inverse fourier transform to see if I retrieve my original time series data. My excel file contains time(xaxis) and distance(yaxis). I already transformed the data into the frequency domain using DFT.

[X] = xlsread('40mgml.xlsx'); %import and read excel file

     xdft = fft(X(:,2)); 
     DT = X(2,1)-X(1,1); % sampling interval -- assuming equal sampling
     Fs = 1/DT;          % sampling frequency
     DF = Fs/size(X,1);
     freq = 0:DF:Fs/2;
     xdft = xdft(1:length(xdft)/2+1);
     plot(freq,abs(xdft))
     xlabel('Frequency (ns^-^1)')
     ylabel('Power (nm^2)')
     set(gca, 'YScale', 'log')
     set(gca, 'XScale', 'log')