I want to estimate the power spectrum of a given signal using Bartlett's method. I understand the general purpose of the method. However, I do not get my head around the algorithmic description of the method given in the Wikipedia article.
The part I am stumbling over, is in the 2nd step:
For each segment, compute the periodogram by computing the discrete Fourier transform (DFT version which does not divide by M), then computing the squared magnitude of the result and dividing this by M.
Why should one square the magnitude before dividing by M? In my mind, it is the other way round: first normalise the magnitude and then square it to get the power.
I see, that the method works, when I implement it on my own. However, I would like to understand better, what I am doing (and why).
The question arises partly because I intend to plot the power estimate (obtained by Bartlett's method) in dB. I am a little unsure whether I should square the result again or not (as this has already been done)? More specifically, when plotting the power estimate in dB - should I use
Thank you in advance!