Signals and systems MCQs : This section focuses on the "Signals and systems". These Multiple Choice Questions (MCQs) should be practiced to improve the Signals and systems skills required for various interviews (campus interview, walk-in interview, company interview), placement, entrance exam and other competitive examinations.
Question 1
Differentiation of ramp signal gives
A. Step signal
B. Impulse signal
C. 1
D. 0
Question 2
Under which condition among the following, will x(t) be a periodic signal?
A. x(t)=x(t+nT), where T=time period and n=natural number.
B. x(t)=x(t+nT), where T=time period and n=whole number.
C. x(t)=x(t+nT), where T=time period and n=integer
D. x(t)=x(t+nT), where T=time period and n=any finite integer.
Question 3
Feedback path is present in-
A. Open system
B. Closed system
C. Both open and closed system
D. Neither present in open nor in closed systems
Question 4
A system where output depends on past and present inputs but not on future inputs is called-
A. Causal system
B. Non causal system
C. Stable system
D. Unstable system
Question 5
A first order system will never be able to give a __________ response band stopband passall pass Choose the correct option
A. 1, 2, 3 true
B. 1 and 3 true, 2 false
C. 1, 2 are true 3 is false
D. 1, 2 are false, 3 is true
Question 6
A signal g(t) = A then g(t) is a
A. energy signal
B. power signal
C. neither energy nor power signal
D. insufficient data
Question 7
A signal m(t) is multiplied by a sinusoidal waveform of frequency fc such thatv(t)=m(t) cos 2pfctIf Fourier transform of m(t) is M(f), Fourier transform of v(t) will be
A. 0.5 M(f + fc)
B. 0.5 M(f - fc)
C. 0.5 M(f + fc) + 0.5 M(f - fc)
D. 0.5 M(f - fc) + 0.5 M(f - fc)
Question 8
A voltage V(t) is a Gaussian ergodic random process with a mean of zero and a variance of 4 volt2. If it is measured by a dc meter. The reading will be
A. 0
B. 4
C. 2
D. 2
Question 9
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%
Question 10
An energy signal has G(f) = 10. Its energy density spectrum is
A. 10
B. 100
C. 50
D. 20
Question 11
An impulse function consist of
A. pure dc
B. pure a.c
C. entire frequency range with constant phase
D. infinite bandwidth with linear phase vaariations
Question 12
As per time displacement theorem in Laplace transformation, displacement in the time domain by T becomes
A. division by s in the s domain
B. division by e-sT in the s domain
C. multiplication by s in the s domain
D. multiplication by e-sT in the s domain
Question 13
Double integration of a unit step function would lead to
A. an impulse
B. a parabola
C. a ramp
D. a doublet
Question 14
δ(t) is a
A. energy signal
B. power signal
C. neither energy nor power
D. none
Question 15
If £[f(t)] = F(s), then £[f(t - T)] =
A. est F(s)
B. e-st F(s)
Question 16
If f(t) = A d(t - a), F(s) is
A. A e-as
B. A eas
C. A a e-as
D. Aa eas
Question 17
If transfer function of a system is H(z) = 6 + z-1 + z-2 then system is
A. minimun phase
B. maximum phase
C. mixed phase
D. none
Question 18
In an ac circuit the fundamental component of current wave lags the corresponding voltage wave by 20°. The third harmonic component of current wave lags the corresponding voltage by an angle.
A. less than 20°
B. more than 20°
C. equal to 20°
D. equal to or more than 20°
Question 19
In Laplace transform, multiplication by e-at in time domain becomes
A. translation by a in s domain
B. translation by (-a) in s domain
C. multiplication by e-as in s domain
D. none of the above
Question 20
The analog signal given below is sampled by 600 samples per second for m(t) = 3 sin 500 pt + 2 sin 700 pt then folding frequency is
A. 500 Hz
B. 700 Hz
C. 300 Hz
D. 1400 Hz
Question 21
The analog signal m(t) is given below m(t) = 4 cos 100 pt + 8 sin 200 pt + cos 300 pt, the Nyquist sampling rate will be
A. 1/100
B. 1/200
C. 1/300
D. 1/600
Question 22
The Fourier series of an odd periodic function contains
A. odd harmonics only
B. even harmonics only
C. cosine harmonics only
D. sine harmonics only
Question 23
The ROC of sequence in the Z.T. of sequence x[n] = an ∪ [n] is
A. z > a
B. z < a
C. |z| > a
D. |z| < a
Question 24
The signal defined by the equations f(t) = 0 for t < 0, f(t) = E for 0 ≤ t ≤ a and f(t) = 0 for t > a is
A. a step function
B. a pulse function
C. a shifted step function originating at t = a
D. none of the above
Question 25
Two function g1(t) and g2(t) with correlation of 6 has average power of 4 and 5 respectively. The power of g1(t) + g2(t) is
A. 9
B. 21
C. 3
D. 15
Question 26
Which one is a causal system?
A. y(n) = 3x[n] - 2x[n - 1]
B. y(n) = 3x[n] + 2x[n + 1]
C. y(n) = 3x[n + 1] + 2x[n - 1]
D. y(n) = 3x[n + 1] 2x[n - 1] + x[n]
Question 27
Which one is a linear system?
A. y[n] = x[n] x x[n - 1]
B. y[n] = x[n] + x[n - 10]
C. y[n] = x2[n]
D. (a) and (c)
Question 28
Which one most appropriate dynamic system?
A. y(n) + y(n - 1) + y(n + 1)
B. y(n) + y(n - 1)
C. y(n) = x(n)
D. y(n) + y(n - 1) + y(n + 3) = 0
Question 29
Z transform is a non-linear operation.
A. TRUE
B. FALSE