Aliasing not sure how to plot.

Thread Starter

wazev

Joined May 26, 2020
9
Alright, so I have a sinus-signal with A = 1, F = 3Hz.
3 Hz means it repeats itself 3 times/second. Then I have a sample frequency of 5 Hz, and if you do theoretical calculations, you get Falias = 5-3 = 2Hz.

My problem? I'm not sure how it should be plotted on the actual graph? (the sample plots with 5Hz sample frequency on my 3Hz signal)
If anyone could show some simple graphics of how this should be done it would be great, and/or simply help me understand where I should put the "dots" in order to plot my sample frequency on my original signal.

//R
 

Papabravo

Joined Feb 24, 2006
14,452
With a sampling frequency of 5 Hz. You can can reconstruct signals in the 0+ to 2.5 Hz. Band. Signals above 2.5 Hz are folded back onto the 0+ to 2.5 Hz band. Your 3 Hz signal would be indistinguishable from a 0.5 Hz signal since that is the difference between 3 Hz and 2.5 Hz.
 
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