# Estimation of Power Spectral Density

I'm learning some basic signal processing to use in my research. So I'm trying to solve this combined signal:

$$x(t)= \text{sin}⁡(60\pi t+\theta)+ 0.5 \text{sin}⁡(120\pi t+\theta)+ 0.3 \text{sin}⁡(240\pi t+\theta)$$

that are uniformly distributed in range $$[0, 2\pi)$$. Duration of the combined signal is 20 seconds.

Select a method (e.g. periodogram estimation, the Bartlett method, the Welch method) for estimation of the Power Spectral Density of the combined digital signal And make a parameter selection for the selected method, that provides the following frequency resolution a) 0.05 Hz b) 0.2 Hz c) 0.5 Hz in the frequency range 0-140 Hz.

How can the Power Spectral Density of the combined digital signal that shown above can be estimated?

• You need to show more of an individual effort than that. Your homework problem lists 3 methods, I'd say choose one and open up a textbook to that section, read the section, try to solve your problem and if you get stuck during that process you can come back with a more specific question – Engineer Apr 6 '20 at 19:48
• i know that i will use welch method for solving that but how how the Power Spectral Density of the combined digital signal that shown above can be calculated. your answer is highly presiated by the way itsnt homwork , its rrefresh for final project – AMEER Apr 6 '20 at 20:40
• If you're using MATLAB and don't mind using the in-built functions, you can look at using pwelch. See the documentation here: uk.mathworks.com/help/signal/ref/pwelch.html – Engineer Apr 6 '20 at 21:11