R4RIN – MCQs, Mock Tests | Electrical measurements Digital Communications MCQs set-2

Find the 8-ary waveform for the word ‘HAPPY’.

1. 4040020246
2. 0440020246
3. 6420200440
4. None of the mentioned

✅ Correct Answer: 2

Find the 32-ary waveform for the word ‘HAPPY’.

1. 280856
2. 658082
3. 288056
4. None of the mentioned

✅ Correct Answer: 1

What are the characteristics of an ideal transmission line?

1. Different amplitude
2. No distortion
3. Time delay
4. All of the mentioned

✅ Correct Answer: 4

The point at which the output signal power has fallen to 0.707 of its peak value is called as _____

1. 3db point
2. Half power point
3. 3db & Half power point
4. None of the mentioned

✅ Correct Answer: 3

The ratio of the filter bandwidth at -60db and -6db amplitude response point is called as _____

1. Half point factor
2. Normalized factor
3. Shape factor
4. None of the mentioned

✅ Correct Answer: 3

As the order of the filter increases, the cost ______ and complexity ______

1. Increases, increases
2. Increases, decreases
3. Decreases, increases
4. Decreases, decreases

✅ Correct Answer: 1

Which filter has maximum flatness?

1. Chebyshev filter
2. Butter-worth filter
3. High pass filter
4. Normalized filter

✅ Correct Answer: 2

The measure of the width of the main lobe is called as ________

1. Null to null bandwidth
2. Half power bandwidth
3. Normalized bandwidth
4. Absolute bandwidth

✅ Correct Answer: 1

SQNR can be improved by _______ sampling rate.

1. Increasing
2. Decreasing
3. Does not depend
4. None of the mentioned

✅ Correct Answer: 1

Which offers better SQNR?

1. Delta modulation
2. PCM
3. Delta modulation & PCM
4. None of the mentioned

✅ Correct Answer: 2

Two functions are called as orthogonal if on integrating the product we get

1. One
2. Zero
3. Infinity
4. None of the mentioned

✅ Correct Answer: 2

Eigen functions are not orthogonal.

1. True
2. False
3.
4.

✅ Correct Answer: 2

Shot noise is produced by

1. Electrons
2. Photons
3. Electrons & Photons
4. None of the mentioned

✅ Correct Answer: 3

Shot noise is avoidable when current is

1. Zero
2. One
3. Infinity
4. None of the mentioned

✅ Correct Answer: 1

Which occurs due to equilibrium fluctuations?

1. Thermal noise
2. Johnson noise
3. Thermal & Johnson noise
4. None of the mentioned

✅ Correct Answer: 3

Flicker noise is called as

1. White noise
2. Pink noise
3. Brown noise
4. None of the mentioned

✅ Correct Answer: 2

Which has the same power spectral density?

1. White noise
2. Brown noise
3. White & Brown noise
4. None of the mentioned

✅ Correct Answer: 1

Which noise is useful for dithering?

1. White noise
2. Pink noise
3. Brown noise
4. None of the mentioned

✅ Correct Answer: 3

Capacity of a channel can be increased by

1. Increasing channel bandwidth
2. Increasing signal power
3. Increasing channel bandwidth &signal power
4. None of the mentioned

✅ Correct Answer: 3

Capacity of the channel can be increased by reducing in band noise power.

1. True
2. False
3.
4.

✅ Correct Answer: 1

Thermal noise is a wide sense stationary process.

1. True
2. False
3.
4.

✅ Correct Answer: 1

The maximum likelihood function is

1. Positive
2. Negative
3. Any of the mentioned
4. None of the mentioned

✅ Correct Answer: 1

Matched filtering operation includes

1. Spectral phase matching
2. Spectral amplitude matching
3. Spectral phase & amplitude matching
4. None of the mentioned

✅ Correct Answer: 3

Matched filter is

1. Linear
2. Non linear
3. Linear & Non linear
4. None of the mentioned

✅ Correct Answer: 1

Which consists of less ISI?

1. Nyquist filter
2. Raised cosine filter
3. Nyquist & Raised cosine filter
4. None of the mentioned

✅ Correct Answer: 2

Digital communication is _______ to environmental changes?

1. Less sensitive
2. More sensitive
3. Does not depend
4. None of the mentioned

✅ Correct Answer: 1

Advantages of digital communication are

1. Easy multiplexing
2. Easy processing
3. Reliable
4. All of the mentioned

✅ Correct Answer: 4

What is necessary for digital communication?

1. Precision timing
2. Frame synchronization
3. Character synchronization
4. All of the mentioned

✅ Correct Answer: 4

What are the disadvantages of digital communication?

1. Needs more bandwidth
2. Is more complex
3. Needs more bandwidth & Is more complex
4. None of the mentioned

✅ Correct Answer: 3

Examples of digital communication are

1. ISDN
2. Modems
3. Classical telephony
4. All of the mentioned

✅ Correct Answer: 4

Which system uses digital transmission?

1. ISDN
2. LANs
3. ISDN & LANs
4. None of the mentioned

✅ Correct Answer: 3

The interval of frequencies outside which the spectrum is zero is called as ________

1. null to null bandwidth
2. normalized bandwidth
3. absolute bandwidth
4. none of the mentioned

✅ Correct Answer: 3

The attenuation level in bounded power spectral density is

1. 35
2. 50
3. 35 & 50
4. none of the mentioned

✅ Correct Answer: 3

Synchronization available in digital communication are

1. Symbol synchronization
2. Frame synchronization
3. Carrier synchronization
4. All of the mentioned

✅ Correct Answer: 4

Digital system includes

1. Better encryption algorithm
2. Difficult data multiplexing
3. All of the mentioned
4. None of the mentioned

✅ Correct Answer: 1

Analog to digital conversion includes

1. Sampling
2. Quantization
3. Sampling & Quantization
4. None of the mentioned

✅ Correct Answer: 3

What are the main features of a receiver?

1. Synchronization
2. Multiple parallel receiver chain
3. Synchronization & Multiple parallel receiver chain
4. None of the mentioned

✅ Correct Answer: 3

What conditions must be fulfilled in a good digital communication system?

1. High data rate
2. High fidelity
3. Low transmit power
4. All of the mentioned

✅ Correct Answer: 4

Wired channels are

1. Lossy
2. Lossless
3. Lossy & Lossless
4. None of the mentioned

✅ Correct Answer: 1

The equivalent temperature in a receiver design must be kept

1. Low
2. High
3. Does not affect the receiver
4. None of the mentioned

✅ Correct Answer: 1

Which corrects the sampling time problem in a digital system?

1. Interpolator
2. Decimator
3. Equalizer
4. Filter

✅ Correct Answer: 1

What are the main features of a transmitter?

1. Higher clock speed
2. Linear power amplifier
3. Directional antennas
4. All of the mentioned

✅ Correct Answer: 4

Transmission media used in low frequency band are

1. Air
2. Water
3. Copper cable
4. All of the mentioned

✅ Correct Answer: 4

Transmission media used for medium frequency band are

1. Coaxial cable
2. Copper cable
3. Optical fiber
4. All of the mentioned

✅ Correct Answer: 2

Matched filter technique is used to

1. Increase SNR
2. Decrease SNR
3. SNR is not affected
4. None of the mentioned

✅ Correct Answer: 1

Matched filter can also be used as least squares estimator.

1. True
2. False
3.
4.

✅ Correct Answer: 1

Digital communication system can handle

1. Analog signals
2. 1D signals
3. 2D signals
4. All of the mentioned

✅ Correct Answer: 4

The information source of a digital communication system can be

1. Packetized
2. Continuous
3. Packetized & Continuous
4. None of the mentioned

✅ Correct Answer: 3

Which are the common transmission media used in digital communication system?

1. Coaxial cable
2. Twisted copper cable
3. Radio frequency bands
4. All of the mentioned

✅ Correct Answer: 4

The basic transmission-reception system is a ______ system.

1. Two block system
2. Three block system
3. Four block system
4. None of the mentioned

✅ Correct Answer: 2