A signal m(t) is multiplied by a sinusoidal waveform of frequency fc such that v

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Question
A signal m(t) is multiplied by a sinusoidal waveform of frequency f_c such that
v(t)=m(t) cos 2pf_ct
If Fourier transform of m(t) is M(f), Fourier transform of v(t) will be
Options
A. 0.5 M(f + f_c)
B. 0.5 M(f - f_c)
C. 0.5 M(f + f_c) + 0.5 M(f - f_c)
D. 0.5 M(f - f_c) + 0.5 M(f - f_c)

Correct Answer

0.5 M(f + f_c) + 0.5 M(f - f_c)

Explanation

It is a modulation process. The resultant has (f + f_c) and (f - f_c) terms.

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