Sampling Theorem Quiz | Sampling Theorem Objective Type Questions and Answers

Questions
21 Drawback of using PAM method is
A Due to varying amplitude of carrier, it is difficult to remove noise at receiver
B Bandwidth is very large as compared to modulating signal
C Varying amplitude of carrier varies the peak power required for transmission
D All of the above

Answer: All of the above
22 In Pulse time modulation (PTM),
A Pulse width modulation and pulse position modulation are the types of PTM
B Amplitude of the carrier is constant
C Position or width of the carrier varies with modulating signal
D All of the above

Answer: All of the above
23 In different types of Pulse Width Modulation,
A Centre of the pulse is kept constant
B Leading edge of the pulse is kept constant
C Tail edge of the pulse is kept constant
D All of the above

Answer: All of the above
24 In pulse width modulation,
A Amplitude of the carrier pulse is varied
B Instantaneous power at the transmitter is constant
C Synchronization is not required between transmitter and receiver
D None of the above

Answer: Synchronization is not required between transmitter and receiver
25 In PWM signal reception, the Schmitt trigger circuit is used
A To produce ramp signal
B For synchronization
C To remove noise
D None of the above

Answer: To remove noise
26 In Pulse Position Modulation, the drawbacks are
A Large bandwidth is required as compared to PAM
B Synchronization is required between transmitter and receiver
C None of the above
D Both a and b

Answer: Both a and b
27 As per sampling theorem –
A Twice each cycle of its highest frequency
B Guard time should be as large as possible
C The signal should be sampled at least twice each cycle of its lowest frequency
D Nyquist rate should be as low as possible

Answer: Twice each cycle of its highest frequency
28 In communication the sampling technique leads to –
A Higher speed of communication
B cheaper equipment
C Higher efficiency
D All of the above

Answer: Higher speed of communication
29 Impulse modulation systems, The number of samples required to ensure no loss of information is given by –
A Parsevals theorem
B Fourier transmission
C Nyquist theorem
D None of the these

Answer: Nyquist theorem
30 If the sampling time is less than the Nyquist interval :
A Simpler filters can be used to obtain the original signal
B Channel Capacity increases
C Bandwidth increases
D Guard time becomes less

Answer: Simpler filters can be used to obtain the original signal
31 The scaling of a sequence x[n] by a factor α is given by
A y[n] = α [x[n]]2
B y[n] = α x[n2]
C y[n] = α x[n]
D y[n] = x[n]x[-n]

Answer: y[n] = α x[n]
32 Causal systems are the systems in which
A The output of the system depends on the present and the past inputs
B The output of the system depends only on the present inputs
C The output of the system depends only on the past inputs
D The output of the system depends on the present input as well as the previous outputs

Answer: The output of the system depends on the present and the past inputs
33 Roll-off factor is
A The bandwidth occupied beyond the Nyquist Bandwidth of the filter
B The performance of the filter or device
C Aliasing effect
D None of the above

Answer: The bandwidth occupied beyond the Nyquist Bandwidth of the filter
34 A signal x[n] is anti symmetric or odd when
A x[-n] = x[n] • x[n]
B x[n] = -x[n]
C x[n] = [x[n]]2
D x[-n] = -x[n]

Answer: x[-n] = -x[n]
35 A signal of maximum frequency of 10 kHz is sampled at Nyquist rate. The time interval between two successive sample is –
A 50 µs
B 100 µs
C 1000 µs
D 5 µs

Answer: 50 µs
16 Time reversal of a discrete time signal refers to
A y[n] = x[-n+k]
B y[n] = x[-n]
C y[n] = x[-n-k]
D y[n] = x[n-k]

Answer: y[n] = x[-n]
37 Time shifting of discrete time signal means
A y[n] = x[n-k]
B y[n] = x[-n-k]
C y[n] = -x[n-k]
D y[n] = x[n+k]

Answer: y[n] = x[n-k]
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