Demonstration of linear filtering with DFT

In this program we demonstrate linear filtering operation using DFT. We take sine waves of different frequencies, and plot them. Then we mix all the sine waves to make a composite signal. We take DFT of the composite signal and plot it to show that all the frequencies are present. Then we multiply a mask to the DFT signal to filter the signal. Then we take IDFT and again plot the filtered signal. The plot demonstrates that indeed the signal has been filtered. A low pass filter is implemented in the example.

The program will be beneficial for undergraduate students.

I will update the program with labels for figures and remarks/comments on the code in short time.