Question

As an engineer, you are required to design a digital modulator to send information. One of the important parameter that you are required to determine is the sampling frequency of the modulator. Discuss how you determine the sampling frequency and provide justification to support your answer.

Answer 1

For any modulator, Sampling frequency should obey nyquist criteria.

Justification:

Nyquist theorem states that for a band limited signal it's sampling frequency should be greater than or equal to two times of the frequency of the message signal or the information.

Fs >= 2* Fm

Where,

Fs = Sampling frequency

Fm = message frequency

If we won't select fs<2*fm then aliasing occurs.

Aliasing means overlapping of the signal.

If message signal is overlapped then some information will be lost.

And it is difficult to reconstruct the signal at receiver end.

Note: If you haven't get any point let me know.

I will try to explain.

Thanks