%% SFDR from Periodogram
% Obtain the power spectrum of a 10 MHz tone with amplitude 1 sampled at 100 MHz. There is a spur at the 1st harmonic (20 MHz) with an amplitude of 3.16\times10^{-4}. Use the one-sided power spectrum and a vector of corresponding frequencies in Hz to compute the SFDR.

deltat = 1e-8;
fs = 1/deltat;
t = 0:deltat:1e-6-deltat;
x = cos(2*pi*10e6*t)+3.16e-4*cos(2*pi*20e6*t);
[sxx,f] = periodogram(x,rectwin(length(x)),length(x),fs,'power');
r = sfdr(sxx,f,'power');

%
% Display the spectrum of the signal. Annotate the fundamental, the DC value, the first spur, and the SFDR.

sfdr(sxx,f,'power');

% Copyright 2015 The MathWorks, Inc.