Question 1

(GATE 2019 || EC || PYQ || NAT || 1 MARKS)
12
Question 2
Let the input be u and the output be y of a system, and the other parameters are real constants. Identify which among the following systems is not a linear system:
(GATE 2018 || EC || [PYQ || MCQ || 1 MARKS)


y = au + b, b ≠ 0
y = au
Question 3
Consider a single input single output discrete-time system with x[n] as input y[n] as output, where the two are related as

Which one of the following statements is true about the systems?
(GATE 2017 || EC || PYQ || MCQ || 1 MARKS)
It is causal and stable.
It is causal but not stable.
It is not causal but stable.
It is neither causal nor stable.
Question 4
The input x(t) and output y(t) of a system are related as

The system is
(GATE 2012 || EC || PYQ || MCQ || 2 MARKS)
time-invariant and stable.
stable and not time-invariant.
time-invariant and not stable.
not time-invariant and not stable.
Question 5
Let x(t) be the input and y(t) be the output of a continuous time system. Match the system properties P1, P2 and P3 with system relations R1, R2, R3, R4.
Properties
P1: Linear but NOT time-invariant
P2: Time-invariant but NOT linear
P3: Linear and time-invariant
Relations
R1: y(t) = t2x(t)
R2: y(t) = t|x(t)|
R3: y(t) = |x(t)|
R4: y(t) = x(t – 5)
(GATE 2008 || EC || PYQ || MCQ || 2 MARKS)
(P1, R1), (P2, R3), (P3, R4).
(P1, R2), (P2, R3), (P3, R4).
(P1, R3), (P2, R1), (P3, R2).
(P1, R1), (P2, R2), (P3, R3)
Question 6
The input and output of a continuous time system are respectively denoted by x(t) and y(t). Which of the following descriptions corresponds to a causal system?
(GATE 2008 || EC || PYQ || MCQ || 1 MARKS)
y(t) = x(t – 2) + x(t + 4)
y(t) = (t – 4)x(t + 1)
y(t) = (t + 4)x(t – 1)
y(t) = (t + 5)x(t + 5)
Question 7
A system with input x[n] and output y[n] is given as

The system is
(GATE 2006 || EC || PYQ || MCQ || 2 MARKS)
Linear, stable and invertible
non-linear, stable and non-invertible
Linear, stable and non-invertible
linear, unstable and invertible
Question 8
Let P be linearity, Q be time-invariance, R be causality and S be stability. A discrete-time system has the input-output relationship

where x(n) is the input and y(n) is the output. The above system has the properties
(GATE 2003 || EC || PYQ || MCQ || 2 MARKS)
P, S but not Q, R.
P, Q, S but not R.
P, Q, R, S.
Q, R, S but not P.
Question 9
A system with an input x(t) and output y(t) is described by the relation: y(t)=tx(t). This system is
(GATE 2000 || EC || PYQ || MCQ || 1 MARKS)
linear and time-invariant
linear and time varying
non-linear and time-invariant
non-linear and time-varying
Question 10
There are 18 questions to complete.