PSD (Power Spectral Density) & CDF (Cumulative Distribution Function)

The users manual tells what the spectrum analyzer graph indicates reference in reference to PSD & CDF. However, it doesn’t give an explanation of what these are and what they mean to me. May I get some insights on these?

So, the CDF vertical axis on the Spectrum Analyzer shows how often and the strength of noise that occurs on a particular frequency.

Here is an example picture:

As you go higher on the graph, you have stronger noise, Higher PSD, depending on how frequently the noise occurs it will be a different color (indicating CDF). Where I marked with green lines is very infrequent noise, Where I marked with the black arrow is noise that is always present (for my area it’s the background noise)

Think of the color scale as being upside down, going from 1 to 100%. Purple being near one and red being 100% of the time noise at that level is measured as being present.

the PSD is the signal strength of the noise that is heard and the CDF is how frequently the noise is present.

I had the impression that the graph was upside down, from what I was reading. Thank you for the explanation. Now that my impression is confirmed, your explanation makes perfect sense.