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Free download in PDF Digital Modulation Techniques Multiple Choice Questions with Answers for competitive exams. These short objective type questions with answers are very important for Board exams as well as competitive exams. These short solved questions or quizzes are provided by Gkseries.
61
Matched filter may be optimally used only for
[A]
Gaussian noise
[B]
Transit time noise
[C]
Flicker
[D]
All of the above
62
T1 carrier system is used
[A]
For PCM voice transmission
[B]
For delta modulation
[C]
For frequency modulated signals
[D]
None of the above
Answer: For PCM voice transmission
63
The maximum data transmission rate in T1 carrier system is
[A]
1.544 megabits per second
[B]
1000 megabits per second
[C]
5.6 megabits per second
[D]
2.6 megabits per second
Answer: 1.544 megabits per second
64
In Adaptive Delta Modulation, the slope error reduces and
[A]
Quantization error increases
[B]
Quantization error remains same
[C]
Quantization error decreases
[D]
None of the above
Answer: Quantization error increases
65
The digital modulation scheme in which the step size is not fixed is
[A]
Delta modulation
[B]
Adaptive delta modulation
[C]
DPCM
[D]
PCM
Answer: Adaptive delta modulation
66
The digital modulation technique in which the step size is varied according to the variation in the slope of the input is called
[A]
Delta modulation
[B]
PCM
[C]
Adaptive delta modulation
[D]
PAM
Answer: Adaptive delta modulation
67
The crest factor of a waveform is given as –
[A]
2Peak value/ rms value
[B]
rms value / Peak value
[C]
Peak value/ rms value
[D]
Peak value/ 2rms value
Answer: Peak value/ rms value
68
Granular noise occurs when
[A]
Step size is too small
[B]
Step size is too large
[C]
There is interference from the adjacent channel
[D]
Bandwidth is too large
Answer: Step size is too large
69
The factors that cause quantizing error in delta modulation are
[A]
Slope overload distortion
[B]
Granular noise
[C]
White noise
[D]
Both a and b are correct
Answer: Both a and b are correct
70
The noise that affects PCM
[A]
Transmission noise
[B]
Quantizing noise
[C]
Transit noise
[D]
Both a and b are correct
Answer: Both a and b are correct
71
DPCM suffers from
[A]
Slope over load distortion
[B]
Quantization noise
[C]
Both a & b
[D]
None of the above
72
DPCM is a technique
[A]
Where digital codes are the quantized values of the predicted value
[B]
Where difference between successive samples of the analog signals are encoded into n-bit data streams
[C]
To convert analog signal into digital signal
[D]
All of the above
73
In Differential Pulse Code Modulation techniques, the decoding is performed by
[A]
Accumulator
[B]
Quantizer
[C]
Sampler
[D]
PLL
74
In Delta Modulation, the bit rate is
[A]
N times the sampling frequency
[B]
N times the modulating frequency
[C]
N times the nyquist criteria
[D]
None of the above
Answer: N times the sampling frequency
75
In digital transmission, the modulation technique that requires minimum bandwidth is
[A]
Delta modulation
[B]
PCM
[C]
DPCM
[D]
PAM
76
In Delta modulation,
[A]
One bit per sample is transmitted
[B]
All the coded bits used for sampling are transmitted
[C]
The step size is fixed
[D]
Both a and c are correct
Answer: Both a and c are correct
77
The error probability of a PCM is
[A]
Calculated using noise and inter symbol interference
[B]
Gaussian noise + error component due to inter symbol interference
[C]
Calculated using power spectral density
[D]
All of the above
78
The expression for bandwidth BW of a PCM system, where v is the number of bits per sample and fm is the modulating frequency, is given by
[A]
BW ≥ vfm
[B]
BW ≤ vfm
[C]
BW ≥ 2 vfm
[D]
BW ≥ 1/2 vfm
79
One of the disadvantages of PCM is
[A]
It requires large bandwidth
[B]
Very high noise
[C]
Cannot be decoded easily
[D]
All of the above
Answer: It requires large bandwidth
80
In PCM, the parameter varied in accordance with the amplitude of the modulating signal is
[A]
Phase
[B]
Amplitude
[C]
Frequency
[D]
None of the above
Answer: None of the above
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