Answer:
Sampling rate = 90
23 and 45 Hz
Explanation:
The Nyquist criteria states that the sampling frequency must be at least twice of the highest frequency component.
(a) We have 10, 12, 13, 23, and 45 Hz signals
The highest frequency component in this list is 45 Hz
So minimum sampling frequency needed to avoid aliasing would be
Sampling rate = 2*45 = 90 sps
Hence a sampling rate of 90 samples per second would be required to avoid aliasing.
(b) if a sampling rate of 40 sps is used then
40 = 2*f
f = 40/2 = 20 Hz
Hence 23 and 45 Hz components will be aliased.
