a) Compute and plot the 128 point FFT of a 0.125Hz cosine wave:
1) Set t=0:1/16:80;
2) Set t=0:2/16:80;
Compare the differences in the FFT result. Explain why even though the inputs to both FFTs are the same cosine waves, the shapes of the FFTs are different.
b) Calculate and plot the 512-point FFT of the same signal as in part (a), and compare the results.
c) Using the same signal as in part (a), but change the setting to:
1) Set t=0:1/16:8;
2) Set t=0:2/16:8;
Calculate, plot and compare the results of the 512-point FFT of the above signal. What is unique about the way it looks and why?