HW2-A Ben Horst ECE301Fall2008mboutin - Rhea

The function I chose (at random) from homework1 can be found here.

The function x(t) = cos(t) is periodic in CT, as its period is 2$ \pi $. However, it is not periodic in DT.

Here is the function sampled at a frequency of 5 samples/unit:

cos(t) sampled at 5 per unit

The sampling shown based on index

Here is the function sampled at $ {\pi \over 2} $ (as closely as MATLAB is able to approximate pi)

cos(t) shown sampled at pi/2 per unit

The sampling shown based on index

Notice that the first image of values (from the first sampling) are not periodic. There is no integer 'N' such that sampling(n) = sampling(n+N). However, in the second case, this does occur. One may observe that sampling(n) = sampling(n+10). Thus, the second case is periodic.