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    %% Periodogram Using Default Inputs
% Obtain the periodogram of an input signal consisting of a discrete-time
% sinusoid with an angular frequency of $\pi/4$ rad/sample with additive
% $N(0,1)$ white noise.

% Copyright 2015 The MathWorks, Inc.


%%
% Create a sine wave with an angular frequency of $\pi/4$ rad/sample with
% additive $N(0,1)$ white noise. The signal is 320 samples in length.
% Obtain the periodogram using the default rectangular window and DFT
% length. The DFT length is the next power of two greater than the signal
% length, or 512 points. Because the signal is real-valued and has even
% length, the periodogram is one-sided and there are 512/2+1 points.

n = 0:319;
x = cos(pi/4*n)+randn(size(n));
[pxx,w] = periodogram(x);
plot(w,10*log10(pxx))

%%
% Repeat the plot using |periodogram| with no outputs.

periodogram(x)