R4RIN – MCQs, Mock Tests | Electrical measurements Digital Communications MCQs set-7

M-ary signalling produces _______ error performance with orthogonal signalling and _______ error performance with multiple phase signalling.

1. Degraded, improved
2. Improved, degraded
3. Improved, improved
4. Degraded, degraded

✅ Correct Answer: 2

Which is more vulnerable to noise?

1. 2-ary system
2. 4-ary system
3. Binary system
4. None of the mentioned

✅ Correct Answer: 2

In which system, bit stream is portioned into even and odd stream?

1. BPSK
2. MSK
3. QPSK
4. FSK

✅ Correct Answer: 3

The error performance of MPSK ______ as M or k increases.

1. Increases
2. Decreases
3. Stays constant
4. None of the mentioned

✅ Correct Answer: 2

In MPSK adding new signals _______ make it vulnerable to noise and in MFSK _______ make it vulnerable.

1. Does, does not
2. Does not, does
3. Does, does
4. Does not, does not

✅ Correct Answer: 1

In orthogonal signalling with symbols containing more number of bits we need ____ power.

1. More
2. Less
3. Double
4. None of the mentioned

✅ Correct Answer: 1

For FSK signalling, WT is equal to

1. 0
2. 1
3. 0.737
4. Infinity

✅ Correct Answer: 2

Energy per symbol Es is given as

1. Es=Eb(log2M)
2. Es=Eb/(log2M)
3. Es=2Eb(log2M)
4. Es=Eb/2(log2M)

✅ Correct Answer: 1

The relation between the probability of bit error and probability of symbol error in M-ary orthogonal signalling is

1. M/M-1
2. 2M/M-1
3. (M/2)/M-1
4. M/M+1

✅ Correct Answer: 3

As limit of k increases, the ratio of PB/PE becomes

1. 1:2
2. 2:1
3. 1:3
4. 3:1

✅ Correct Answer: 1

Link budget consists of calculation of

1. Useful signal power
2. Interfering noise power
3. Useful signal & Interfering noise power
4. None of the mentioned

✅ Correct Answer: 3

Link budget can help in predicting

1. Equipment weight and size
2. Technical risk
3. Prime power requirements
4. All of the mentioned

✅ Correct Answer: 4

Which is the primary cost for degradation of error performance?

1. Loss in signal to noise ratio
2. Signal distortion
3. Signal distortion & Loss in signal to noise ratio
4. None of the mentioned

✅ Correct Answer: 3

Which factor adds phase noise to the signal?

1. Jitter
2. Phase fluctuations
3. Jitter & Phase fluctuations
4. None of the mentioned

✅ Correct Answer: 3

Antennas are used

1. As transducer
2. To focus
3. As transducer & To focus
4. None of the mentioned

✅ Correct Answer: 3

Mechanism contributing to a reduction in efficiency is called as

1. Amplitude tapering
2. Blockage
3. Edge diffraction
4. All of the mentioned

✅ Correct Answer: 4

Space loss occurs due to a decrease in

1. Electric field strength
2. Efficiency
3. Phase
4. Signal power

✅ Correct Answer: 1

Antenna’s efficiency is given by the ratio of

1. Effective aperture to physical aperture
2. Physical aperture to effective aperture
3. Signal power to noise power
4. Losses

✅ Correct Answer: 1

Effective radiated power of an isotropic radiator can be given as a product of

1. Radiated power and received power
2. Effective area and physical area
3. Transmitted power and transmitting gain
4. Receiving power and receiving gain

✅ Correct Answer: 3

According to reciprocity theorem, _____ and _____ are identical.

1. Transmitting power and receiving power
2. Transmitting gain and receiving gain
3. Effective area and physical area
4. None of the mentioned

✅ Correct Answer: 2

Field of view is ______ to antenna gain.

1. Proportional
2. Inversely proportional
3. Half the
4. Double

✅ Correct Answer: 2

Antenna gain ______ as effective area increases.

1. Increases
2. Decreases
3. Remains same
4. None of the mentionedv

✅ Correct Answer: 1

The beam-width becomes narrower on

1. Increasing frequency
2. Increasing antenna size
3. Increasing frequency & antenna size
4. None of the mentioned

✅ Correct Answer: 3

Path loss Ls is dependent on

1. Signal power
2. Effective area
3. Wavelength
4. Antenna size

✅ Correct Answer: 3

Thermal noise is generated due to

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

✅ Correct Answer: 1

In analog receivers, noise bandwidth is _________ signal bandwidth.

1. Lesser than
2. Greater than
3. Equal to
4. Not related View Answer

✅ Correct Answer: 2

The link availability measures the percentage of time the link can be ______

1. Open
2. Closed
3. Used
4. None of the mentioned

✅ Correct Answer: 2

Visibility is ________ to required availability.

1. Proportional
2. Inversely proportional
3. Equal
4. Not related

✅ Correct Answer: 2

The stop and wait ARQ needs _______ connection.

1. Half duplex
2. Full duplex
3. Simplex
4. None of the mentioned

✅ Correct Answer: 1

In continuous ARQ will pullback uses _____ system.

1. Half duplex
2. Full duplex
3. Simplex
4. None of the mentioned

✅ Correct Answer: 2

Which method requires less redundancy?

1. Error detection
2. Error correction
3. Error detection & correction
4. None of the mentioned

✅ Correct Answer: 1

Hybrid automatic repeat request is a combination of

1. ARQ and error correction code
2. ARQ and error detection code
3. Error detection and correction codes
4. One of the mentioned

✅ Correct Answer: 1

Automatic repeat request is also called as

1. Forward error correction
2. Backward error correction
3. Forward & Backward error correction
4. None of the mentioned

✅ Correct Answer: 2

Error detection is realized using

1. Hash function
2. Check sum
3. Hash function & Check sum
4. None of the mentioned

✅ Correct Answer: 2

Check-sum scheme has

1. Check bits
2. Parity bits
3. Longitudinal redundancy bits
4. All of the mentioned

✅ Correct Answer: 4

Example of block code is

1. Hamming code
2. Reed-solomon code
3. Repetition code
4. All of the mentioned

✅ Correct Answer: 4

Noise figure measures the

1. Power degradation
2. Noise degradation
3. SNR degradation
4. None of the mentioned

✅ Correct Answer: 3

Noise figure is a parameter that represents a ______ of the system.

1. Noisiness
2. Efficiency
3. Maximum output
4. Maximum power handling capacity

✅ Correct Answer: 1

When two networks are connected in series, its composite noise figure can be given as

1. F1+(F2-1)/G1
2. F1-(F2-1)/G1
3. F2+(F1-1)/G1
4. F1G1+(F2-1)

✅ Correct Answer: 1

The space window region ranges from

1. 1GHz to 10 GHz
2. 10GHz to 100GHZ
3. 5GHz to 50GHz
4. 1MHz to 10MHz

✅ Correct Answer: 1

Atmospheric window region is used for

1. Satellite communication
2. Deep-space communication
3. Satellite & Deep-space communication
4. None of the mentioned

✅ Correct Answer: 3

Which parameter is referred to as receiver sensitivity?

1. S/N ratio
2. G/T ratio
3. EIRP
4. PR/N0

✅ Correct Answer: 2

What are the functions of satellite repeaters?

1. Re transmits
2. Regenerates
3. Reconstitutes
4. All of the mentioned

✅ Correct Answer: 4

What are the functions of non-regenerative repeaters?

1. Amplifies
2. Re transmits
3. Amplifies & Re transmits
4. None of the mentioned

✅ Correct Answer: 3

In which repeaters uplink is decoupled from the downlink?

1. Regenerative
2. Non regenerative
3. Regenerative & Non regenerative
4. None of the mentioned

✅ Correct Answer: 1

AM-to-AM conversion brings about

1. Amplitude variation
2. Phase variation
3. Frequency variation
4. None of the mentioned

✅ Correct Answer: 1

AM-to-PM conversion brings about

1. Amplitude variation
2. Phase variation
3. Frequency variation
4. None of the mentioned

✅ Correct Answer: 2

Channel coding relates to area such as

1. Waveform coding
2. Structured sequence
3. Waveform coding & Structured sequence
4. None of the mentioned

✅ Correct Answer: 3

Examples of structured sequences are

1. Block codes
2. Convolutional codes
3. Turbo codes
4. All of the mentioned

✅ Correct Answer: 4

Antipodal signals are

1. Mirror images
2. 1800 apart
3. One is negative of the other
4. All of the mentioned

✅ Correct Answer: 4