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Communication Systems - Engineering

Q1:

The number of spectral component when two sine wave of same frequency multiplied is

A 2

B 3

C ∞

D 4

ANS:B - 3

@Mukund

It can also be like sin(wt)sin(wt) = sin^2(wt) = (1-cos(2wt))/2 = (0.5) - 0.5cos(2wt).

So only 0.5 will have 0 frequency component and cos term Fourier transform have 2 component θ +2w and θ -2w.

So, a total 3 spectral components.