Electronics and Communication Engineering - Signals and Systems
Exercise : Signals and Systems - Section 4
- Signals and Systems - Section 1
- Signals and Systems - Section 2
- Signals and Systems - Section 3
- Signals and Systems - Section 4
- Signals and Systems - Section 5
- Signals and Systems - Section 6
- Signals and Systems - Section 7
- Signals and Systems - Section 8
- Signals and Systems - Section 9
- Signals and Systems - Section 10
11.
The function δ(t - b) is
Answer: Option
Explanation:
δ(t) is an impulse at t = 0, δ(t - b) is in impulse originating at t = b.
12.
An ac network has a power factor of 0.8 lagging for fundamental frequency. If the applied voltage contains thrid and fifth harmonics, the overall power factor will be
Answer: Option
Explanation:
As frequency increases, XL decreases and power factor becomes worse.
13.
what will be sampling rate to aviod aliasing for the signal m(t) = 10 cos 100 pt?
≤ 100 n2
≥ 100 n2
Answer: Option
Explanation:
To avoid aliasing fs ≤ 2fm
.
14.
If Laplace transform of f(t) is F(s), then 
=
=s F(s) - f(0-)
s F(s) + f(0-)
Answer: Option
Explanation:
£f(t) = 
£-1F(s) = f(t)
£[a f1(t) + bf2(t)] = aF1(s) + bF2(s)
where 
£[f(t - T)] = e-sT F(s)
£[e-at f(t)] = F(s + a)
Initial value theorem 
Final value theroem 
Convolution Integral 
where t is dummy variable for t.
15.
Choose the function f(t), - ∞ < t < + ∞, for which a Fourier series cannot be defined
Answer: Option
Explanation:
Fourier series is applicable for periodic or finite duration signal and (c) is neither periodic nor finite duration signal.
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