Quiz-1: 3rd February 2022
Signals & systems
Syllabus: Lecture-00 to 10
Total Marks: 20
1) A system is defined as
y(t) = x(3t)
The system is:
(a) Causal & Time Invariant
(b) Causal & Time Variant
(c) Non-causal & Time Invariant
(d) Non-causal & Time Variant
Ans: (d)
Marks: 1
2) A signal x(t) is shown in the figure below
The signal can be represented as,
(a) u(t+1) – (1-e-at)u(t)
(b) u(-t) – u(-t-1) + e-atu(t)
(c) none of the these.
(d) both of these.
Ans: (d)
Marks: 1
3) Signals f(t) and g(t) are shown below.
Express g(t) in terms of f(t).
(a) g(t) = f(2t+1)
(b) g(t) = f(2t-1)
(c) g(t) = f(2t)
(d) g(t) = f(2t-0.5)
Ans: (b)
Marks: 1
4) A signal x(t) is shown below
Signal g(t) = x(-t-2) will be.
(a)
(b)
(c)
(d)
Ans: (a)
Marks: 1
5) A system is defined as:
y(t) = 2x(t) + e(t+2)
The system is,
(a) Linear and Time Invariant
(b) Non-linear and Time Invariant
(c) Non-linear and Time Variant
(d) Linear and Time Variant
Ans: (C)
Marks: 1
6) A signal x(t) is shown below
Signal g(t) = x(t) + x(1 − t) will be,
(a)
(b)
(c)
(d)
Ans: (a)
Marks: 2
7) Two systems are cascaded as shown below.
The impulse responses of the two systems are
If a1={a1}, a2={a2}, a3={a3}, a4={a4}. And b1={b1}, b2={b2}, b3={b3}.
Then what is the value of h[2], where h[n]is the effective impulse response of the effective system?
Ans: a2*b3 + a3*b2 + a4*b1
Marks: 2
8) The output of a system y[n] for an input x[n], is given by
Assuming zero initial condition (initial rest condition), what is the value of h[3], if h[n] represents
impulse response of the system.
Ans: A3 + 2AB
Marks: 2
9) Two systems are connected as shown below.
The impulse responses of the two systems are
If a1={a1}, a2={a2}, a3={a3}, a4={a4}. And b1={b1}, b2={b2}, b3={b3}.
Then what is the value of h[1], where h[n]is the effective impulse response of the effective system?
Ans: a2+b3
Marks: 2
10) What is the value of the integral
when the value of a= {a}?
Ans: {a}^2
Marks: 1
11) If x(t) = {a} t2 + {b} t + {c}. Then, what is the value of the following integral
at t = {t}?
Ans: {a}*{t}*{t} + {b}*{t} + {c}
Marks: 1
12) The input x(t) and output y(t) of a system are related by
Is this system invertible?
Ans: No
Marks: 1
13) A signal is given by
Is this signal periodic?
Ans: No
Marks: 1
14) The input x(t) and output y(t) of a system are related by
Is this system stable?
Ans: Yes
Marks: 1
15) The input x(t) and output y(t) of a system are related by
Is this system causal?
Ans: Yes
Marks: 1
16) Impulse response of a system is given by,
If a>0, then the system is
a) Causal & stable
b) Non-causal & stable
c) Causal & unstable
d) Non-causal & unstable
Ans: d
Marks: 1