title: How can I use spectrogram and/or periodogram to plot a PSD?
body: <p>I have a &lt;1,000,000x1 double> vector of m/s^2 data from an accelerometer. I'd like to create a power spectral density plot of this data (power/hz vs frequency). 
  I can run the vector through spectrogram to find frequencies, but I may be using windows incorrectly. I get a &lt;131073x8 complex double> returned but I don't know what it's contents are.
  Can I simply use the function periodogram on my vector to plot power/hz vs frequency? I have tried and matlab returns a blank plot.</p>
  
  <p>Support on this would be very appreciated..
  Thank you,
  Alex</p>