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This set of Digital Communication Multiple Choice Questions & Answers (MCQs) focuses on Digital Communication Set 1
Q1 | In uniform quantization process
- the step size remains same
- step size varies according to the values of the input signal
- the quantizer has linear characteristics
- both a and c are correct
Q2 | The process of converting the analog sample into discrete form is called
- modulation
- multiplexing
- quantization
- sampling
Q3 | The characteristics of compressor in μ-law companding are
- continuous in nature
- logarithmic in nature
- linear in nature
- discrete in nature
Q4 | The modulation techniques used to convert analog signal into digitalsignal are
- pulse code modulation
- delta modulation
- adaptive delta modulation
- all of the above
Q5 | The sequence of operations in which PCM is done is
- sampling, quantizing, encoding
- quantizing, encoding, sampling
- quantizing, sampling, encoding
- none of the above
Q6 | In PCM, the parameter varied in accordance with the amplitude of themodulating signal is
- amplitude
- frequency
- phase
- none of the above
Q7 | One of the disadvantages of PCM is
- it requires large bandwidth
- very high noise
- cannot be decoded easily
- all of the above
Q8 | The expression for bandwidth BW of a PCM system, where v is thenumber of bits per sample and fm is the modulating frequency, is given by
- bw ≥ vfm
- bw ≤ vfm
- bw ≥ 2 vfm
- bw ≥ 1/2 vfm
Q9 | The error probability of a PCM is
- calculated using noise and inter symbol interference
- gaussian noise + error component due to inter symbol interference
- calculated using power spectral density
- all of the above
Q10 | In Delta modulation,
- one bit per sample is transmitted
- all the coded bits used for sampling are transmitted
- the step size is fixed
- both a and c are correct
Q11 | In digital transmission, the modulation technique that requiresminimum bandwidth is
- delta modulation
- pcm
- dpcm
- pam
Q12 | In Delta Modulation, the bit rate is
- n times the sampling frequency
- n times the modulating frequency
- n times the nyquist criteria
- none of the above
Q13 | In Differential Pulse Code Modulation techniques, the decoding isperformed by
- accumulator
- sampler
- pll
- quantizer
Q14 | DPCM suffers from
- slope over load distortion
- quantization noise
- both a & b
- none of the above
Q15 | The noise that affects PCM
- transmission noise
- quantizing noise
- transit noise
- both a and b are correct
Q16 | The factors that cause quantizing error in delta modulation are
- slope overload distortion
- granular noise
- white noise
- both a and b are correct
Q17 | Granular noise occurs when
- step size is too small
- step size is too large
- there is interference from the adjacent channel
- bandwidth is too large
Q18 | The crest factor of a waveform is given as –
- 2peak value/ rms value
- rms value / peak value
- peak value/ rms value
- peak value/ 2rms value
Q19 | The digital modulation technique in which the step size is variedaccording to the variation in the slope of the input is called
- delta modulation
- pcm
- adaptive delta modulation
- pam
Q20 | The digital modulation scheme in which the step size is not fixed is
- delta modulation
- adaptive delta modulation
- dpcm
- pcm
Q21 | In Adaptive Delta Modulation, the slope error reduces and
- quantization error decreases
- quantization error increases
- quantization error remains same
- none of the above
Q22 | The number of voice channels that can be accommodated fortransmission in T1 carrier system is
- 24
- 32
- 56
- 64
Q23 | The maximum data transmission rate in T1 carrier system is
- 2.6 megabits per second
- 1000 megabits per second
- 1.544 megabits per second
- 5.6 megabits per second
Q24 | T1 carrier system is used
- for pcm voice transmission
- for delta modulation
- for frequency modulated signals
- none of the above
Q25 | Matched filter may be optimally used only for
- gaussian noise
- transit time noise
- flicker
- all of the above