R4RIN – MCQs, Mock Tests | Electrical measurements Digital Communications MCQs set-4

The main sources of corruption are

1. Sampling and quantizing effects
2. Channel effects
3. Sampling, quantizing and channel effects
4. None of the mentioned

✅ Correct Answer: 3

The distortion in quantization is called as

1. Round off error
2. Truncation error
3. Round off & Truncation error
4. None of the mentioned

✅ Correct Answer: 3

In quantization process, the amount of quantization noise is _______________ to number of levels.

1. Directly proportional
2. Inversely proportional
3. Independent
4. None of the mentioned

✅ Correct Answer: 2

Saturation noises can be avoided or reduced by

1. Automatic gain control
2. Amplifying
3. Filtering
4. None of the mentioned

✅ Correct Answer: 1

Timing jitter can be reduced by

1. Good power supply isolation
2. Stable clock reference
3. Good power supply isolation & Stable clock reference
4. None of the mentioned

✅ Correct Answer: 3

The reasons for the threshold effect are

1. Thermal noise
2. Interference from other users
3. Interference from circuit switching transients
4. All of the mentioned

✅ Correct Answer: 4

When channel bandwidth is greater than the pulse bandwidth, it causes

1. Intersignal interference
2. Intersymbol interference
3. Bandwidth error
4. None of the mentioned

✅ Correct Answer: 2

The _____________ corresponds to average quantization noise power.

1. Mean
2. Variance
3. Probability density function
4. None of the mentioned

✅ Correct Answer: 2

Signal to noise ratio increases as ___________ increases.

1. Quantization level
2. Square of quantization level
3. Square root of quantization level
4. None of the mentioned

✅ Correct Answer: 2

Signal to noise ratio is infinite when

1. Quantization noise is zero
2. Number of levels are infinite
3. Quantization noise is zero & Number of levels are infinite
4. None of the mentioned

✅ Correct Answer: 3

The length of the code-word obtained by encoding quantized sample is equal to

1. l=log(to the base 2)L
2. l=log(to the base 10)L
3. l=2log(to the base 2)L
4. l=log(to the base 2)L/2

✅ Correct Answer: 1

Quantization noise can be reduced by ________ the number of levels.

1. Decreasing
2. Increasing
3. Doubling
4. Squaring

✅ Correct Answer: 2

In PCM encoding, quantization level varies as a function of ________

1. Frequency
2. Amplitude
3. Square of frequency
4. Square of amplitude

✅ Correct Answer: 2

What is bit depth?

1. Number of quantization level
2. Interval between two quantization levels
3. Number of possible digital values to represent each sample
4. None of the mentioned

✅ Correct Answer: 3

Choosing a discrete value that is near but not exactly at the analog signal level leads to

1. PCM error
2. Quantization error
3. PAM error
4. Sampling error

✅ Correct Answer: 2

In PCM the samples are dependent on ________

1. Time
2. Frequency
3. Quanization leavel
4. Interval between quantization level

✅ Correct Answer: 1

DPCM encodes the PCM values based on

1. Quantization level
2. Difference between the current and predicted value
3. Interval between levels
4. None of the mentioned

✅ Correct Answer: 2

Delta modulation uses _____ bits per sample.

1. One
2. Two
3. Four
4. Eight

✅ Correct Answer: 1

Sample resolution for LPCM ____ bits per sample.

1. 8
2. 16
3. 24
4. All of the mentioned

✅ Correct Answer: 4

Adaptive DPCM is used to

1. Increase bandwidth
2. Decrease bandwidth
3. Increase SNR
4. None of the mentioned

✅ Correct Answer: 2

The size of the quantile interval is called as

1. Inter level
2. Step size
3. Quantile size
4. Level width

✅ Correct Answer: 2

Uniform quantization provides better quantization for

1. Weak signals
2. Strong signals
3. Weak & Strong signals
4. None of the mentioned

✅ Correct Answer: 2

Non uniform quantization provides better quantization for

1. Weak signals
2. Coarse signals
3. Weak & Coarse signals
4. None of the mentioned

✅ Correct Answer: 1

In non uniform quantization, the quantization noise is _______ to signal size.

1. Inversely proportional
2. Directly proportional
3. Equal
4. Double

✅ Correct Answer: 2

The output SNR can be made independent of input signal level by using

1. Uniform quantizer
2. Non uniform quantizer
3. Uniform & Non uniform quantizer
4. None of the mentioned

✅ Correct Answer: 2

Companding is the process of

1. Compression
2. Expansion
3. Compression & Expansion
4. None of the mentioned

✅ Correct Answer: 3

Which value of μ corresponds to linear amplification?

1. μ=0
2. μ=1
3. μ>0
4. μ<0

✅ Correct Answer: 1

What is the standard value of μ in μ-law ?

1. 128
2. 255
3. 256
4. 0

✅ Correct Answer: 2

The standard value of A in A-law is

1. 87
2. 88
3. 86.7
4. 87.6

✅ Correct Answer: 4

Which type of quantization is most preferable for audio signals for a human ear?

1. Uniform quantization
2. Non uniform quantization
3. Uniform & Non uniform quantization
4. None of the mentioned

✅ Correct Answer: 2

Which waveforms are also called as line codes?

1. PCM
2. PAM
3. FM
4. AM

✅ Correct Answer: 1

When pulse code modulation is applied to non binary symbols we obtain waveform called as

1. PCM
2. PAM
3. M-ary
4. line codes

✅ Correct Answer: 3

Examples of PCM waveforms are

1. Non return to zero
2. Phase encoded
3. Multilevel binary
4. All of the mentioned

✅ Correct Answer: 4

Which type is used and preferred in digital logic circuits?

1. NRZ-L
2. NRZ-M
3. NRZ-S
4. None of the mentioned

✅ Correct Answer: 1

Which method is called as differential encoding?

1. NRZ-L
2. NRZ-M
3. NRZ-S
4. None of the mentioned

✅ Correct Answer: 2

Which method is preferred in magnetic tape recording?

1. NRZ-L
2. NRZ-M
3. NRZ-S
4. None of the mentioned

✅ Correct Answer: 2

NRZ-S is complement of _______

1. NRZ-L
2. NRZ-M
3. NRZ-L & NRZ-M
4. None of the mentioned

✅ Correct Answer: 2

The return to zero waveform consists of

1. Unipolar RZ
2. Bipolar RZ
3. RZ-AMI
4. All of the mentioned

✅ Correct Answer: 4

Phase encoded group consists of

1. Manchester coding
2. Bi-phase-mark
3. Miller coding
4. All of the mentioned

✅ Correct Answer: 4

In which waveform logic 1 is represented by half bit wide pulse and logic 0 is represented by absence of pulse?

1. Unipolar RZ
2. Bipolar RZ
3. RZ-AMI
4. Manchester coding

✅ Correct Answer: 1

In which waveform logic 1 and logic 0 are represented by opposite one half bit wide pulses?

1. Unipolar RZ
2. Bipolar RZ
3. RZ-AMI
4. Manchester coding

✅ Correct Answer: 2

In which waveform logic 1 is represented by equal amplitude alternating pulses?

1. Unipolar RZ
2. Bipolar RZ
3. RZ-AMI
4. Manchester coding

✅ Correct Answer: 3

Application of phase encoded binary signals are

1. Optical communication
2. Magnetic recording
3. Satellite telemetry
4. All of the mentioned

✅ Correct Answer: 4

In which waveform one is represented by half bit wide pulse positioned during the first half and zero is represented by half bit wide pulse positioned in the second half?

1. Bi-p-L
2. Bi-p-M
3. Bi-p-S
4. Delay modulation

✅ Correct Answer: 1

Which binary waveform uses three levels?

1. Bipolar RZ
2. RZ-AMI
3. Bipolar RZ & RZ-AMI
4. None of the mentioned

✅ Correct Answer: 3

Which waveform type has the feature of clocking?

1. Manchester coding
2. Bbi-p-M
3. Delay modulation
4. NRZ-L

✅ Correct Answer: 1

Which waveform has the feature of error detection?

1. NRZ-L
2. RZ-AMI
3. Manchester coding
4. Duobinary

✅ Correct Answer: 4

Which waveform scheme introduces bandwidth compression?

1. Duobinary
2. Manchester coding
3. Phase encoded waveform
4. Multilevel codes

✅ Correct Answer: 4

Which waveform type has better noise immunity?

1. NRZ
2. RZ
3. Phase encoded
4. Multilevel codes

✅ Correct Answer: 1

In pulse modulation, reciprocal of T(time) is

1. Bandwidth
2. Symbol rate
3. Signal voltage
4. None of the mentioned

✅ Correct Answer: 2