Types of Periodograms
Periodograms come in many flavors and it is important to know the strengths and weaknesses of those that you use. So far we have employed three basic types:
  1. Box Least Square Periodogram
  2. Generalized Lomb Scargle Periodogram
  3. Phase Dispersion Method Periodogram
Let's continue our focus on the overall picture and avoid getting into the weeds. We will come back to how these periodograms work later. 
How do you know what you're looking at?
Some characteristics to look for: