Electronics and Communication Engineering - Signals and Systems

Exercise :: Signals and Systems - Section 1

31.

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

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)

Answer: Option C

Explanation:

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

Workspace

Report errors

32.

A voltage wave having 5% fifth harmonic content is applied to a series RC circuit. The percentage fifth harmonic content in the current wave will be

A.	5%
B.	more than 5%
C.	less than 5%
D.	equal or more than 5%

Answer: Option B

Explanation:

I_C = V(jωC).

Workspace

Report errors

33.

Assertion (A): If , the initial value of i(t) is 5A

Reason (R): As per initial vaue theroem

A.	Both A and R are correct and R is correct explanation of A
B.	Both A and R are correct but R is not correct explanation of A
C.	A is true, R is false
D.	A is false, R is true