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This section includes InterviewSolutions, each offering curated multiple-choice questions to sharpen your knowledge and support exam preparation. Choose a topic below to get started.

1.

In which repeaters uplink is decoupled from the downlink?(a) Regenerative(b) Non regenerative(c) Regenerative & Non regenerative(d) None of the mentionedThis question was addressed to me in an interview.Origin of the question is Noise Parameters topic in chapter Communication Link Analysis of Digital Communications

Answer»

The correct CHOICE is (a) Regenerative

For explanation: The PRINCIPAL ADVANTAGE of regenerative repeaters over non regenerative repeaters is that the uplink is decoupled from the DOWNLINK so that the uplink noise is not transmitted on the downlink.
Discussion
2.

AM-to-PM conversion brings about(a) Amplitude variation(b) Phase variation(c) Frequency variation(d) None of the mentionedI have been asked this question in an interview for job.My enquiry is from Noise Parameters in section Communication Link Analysis of Digital Communications

Answer»

Right answer is (B) Phase variation

To explain I would SAY: AM-to-PM conversion is ANOTHER common phenomenon in non LINEAR devices. It brings about phase variation that can effect the error PERFORMANCE.
Discussion
3.

AM-to-AM conversion brings about(a) Amplitude variation(b) Phase variation(c) Frequency variation(d) None of the mentionedI had been asked this question during a job interview.Origin of the question is Noise Parameters topic in section Communication Link Analysis of Digital Communications

Answer» RIGHT CHOICE is (a) Amplitude variation

Easiest explanation: AM-to-AM CONVERSION is a PHENOMENON common to non linear devices and it UNDERGOES a non linear transformation and results in amplitude variation.
Discussion
4.

Atmospheric window region is used for(a) Satellite communication(b) Deep-space communication(c) Satellite & Deep-space communication(d) None of the mentionedThis question was posed to me during an interview for a job.My question comes from Noise Parameters topic in chapter Communication Link Analysis of Digital Communications

Answer» CORRECT CHOICE is (c) Satellite & Deep-space communication

The best I can explain: The REGION between 1GHz and 10GHz is called as space WINDOW or ATMOSPHERIC window. Here the temperature will be the lowest. This region is used for satellite communication and deep-space communication.
Discussion
5.

What are the functions of non-regenerative repeaters?(a) Amplifies(b) Re transmits(c) Amplifies & Re transmits(d) None of the mentionedI have been asked this question in an international level competition.My question comes from Noise Parameters in portion Communication Link Analysis of Digital Communications

Answer» CORRECT option is (C) Amplifies & Re transmits

Easiest explanation: A non regenerative REPEATERS can be used with many different modulation formats. It only amplifies and re transmits the message RECEIVED.
Discussion
6.

Which parameter is referred to as receiver sensitivity?(a) S/N ratio(b) G/T ratio(c) EIRP(d) PR/N0I had been asked this question in examination.Question is from Noise Parameters in chapter Communication Link Analysis of Digital Communications

Answer»

Right answer is (B) G/T ratio

Explanation: The figure of PARAMETER G/T0 is called as receiver SENSITIVITY.
Discussion
7.

What are the functions of satellite repeaters?(a) Re transmits(b) Regenerates(c) Reconstitutes(d) All of the mentionedI got this question during an interview for a job.This interesting question is from Noise Parameters topic in portion Communication Link Analysis of Digital Communications

Answer»

Correct ANSWER is (d) All of the mentioned

Easiest explanation: SATELLITE repeaters re transmit the message received. It REGENERATES, demodulates and RECONSTITUTES the digital information embedded in the received WAVEFORM.
Discussion
8.

The space window region ranges from(a) 1GHz to 10 GHz(b) 10GHz to 100GHZ(c) 5GHz to 50GHz(d) 1MHz to 10MHzThe question was asked during an interview.This intriguing question originated from Noise Parameters in division Communication Link Analysis of Digital Communications

Answer»

Correct option is (a) 1GHz to 10 GHz

Explanation: There is a REGION between 1GHz and 10GHz where the temperature will be lowest. This region is called as microwave window or space window.
Discussion
9.

When two networks are connected in series, its composite noise figure can be given as(a) F1+(F2-1)/G1(b) F1-(F2-1)/G1(c) F2+(F1-1)/G1(d) F1G1+(F2-1)I have been asked this question in quiz.I would like to ask this question from Noise Parameters topic in chapter Communication Link Analysis of Digital Communications

Answer» RIGHT ANSWER is (a) F1+(F2-1)/G1

Explanation: When two networks are connected in series, the COMPOSITE noise FIGURE can be written as F1+(F2-1)/G1.
Discussion
10.

Noise figure is a parameter that represents a ______ of the system.(a) Noisiness(b) Efficiency(c) Maximum output(d) Maximum power handling capacityThe question was posed to me in an internship interview.My question is taken from Noise Parameters topic in division Communication Link Analysis of Digital Communications

Answer»

The correct OPTION is (a) Noisiness

To elaborate: Noise FIGURE is a parameter that represents the noisiness of a TWO PORT network or device such as an amplifier, compared with a reference noise.
Discussion
11.

Noise figure measures the(a) Power degradation(b) Noise degradation(c) SNR degradation(d) None of the mentionedI had been asked this question in an internship interview.Question is from Noise Parameters in portion Communication Link Analysis of Digital Communications

Answer»

The CORRECT option is (c) SNR degradation

Easy explanation: Noise FIGURE RELATES the SNR of the input to SNR of the OUTPUT. It MEASURES the SNR degradation caused by the network.
Discussion
12.

Example of block code is(a) Hamming code(b) Reed-solomon code(c) Repetition code(d) All of the mentionedThe question was asked in examination.I'm obligated to ask this question of Link Budget Analysis and Error Control topic in chapter Communication Link Analysis of Digital Communications

Answer»

Right answer is (d) All of the mentioned

Explanation: Some examples of block codes are repetition codes, HAMMING codes, parity CHECK BIT codes, reed-solomon codes, TURBO codes ETC.
Discussion
13.

Check-sum scheme has(a) Check bits(b) Parity bits(c) Longitudinal redundancy bits(d) All of the mentionedThe question was posed to me at a job interview.My question is from Link Budget Analysis and Error Control topic in division Communication Link Analysis of Digital Communications

Answer»

The correct ANSWER is (d) All of the mentioned

The best I can explain: Check-sum SCHEME includes parity bits, longitudinal redundancy bits and check bits.
Discussion
14.

Error detection is realized using(a) Hash function(b) Check sum(c) Hash function & Check sum(d) None of the mentionedThe question was posed to me in quiz.Question is taken from Link Budget Analysis and Error Control topic in portion Communication Link Analysis of Digital Communications

Answer»

The correct OPTION is (b) Check sum

Explanation: Error detection is commonly REALIZED USING a SUITABLE HASH function or check-sum algorithm.
Discussion
15.

Automatic repeat request is also called as(a) Forward error correction(b) Backward error correction(c) Forward & Backward error correction(d) None of the mentionedThis question was addressed to me in an online interview.My question is from Link Budget Analysis and Error Control topic in chapter Communication Link Analysis of Digital Communications

Answer»

Correct choice is (b) BACKWARD error correction

The explanation: Automatic REPEAT REQUEST is ALSO referred to as backward error correction method.
Discussion
16.

Hybrid automatic repeat request is a combination of(a) ARQ and error correction code(b) ARQ and error detection code(c) Error detection and correction codes(d) One of the mentionedI have been asked this question in final exam.This intriguing question originated from Link Budget Analysis and Error Control topic in chapter Communication Link Analysis of Digital Communications

Answer»

The CORRECT choice is (a) ARQ and error CORRECTION code

To explain: An alternate approach for error CONTROL is a hybrid automatic REPEAT request method which is a COMBINATION of ARQ and error correction code.
Discussion
17.

Which method requires less redundancy?(a) Error detection(b) Error correction(c) Error detection & correction(d) None of the mentionedI have been asked this question in an interview for job.I need to ask this question from Link Budget Analysis and Error Control topic in section Communication Link Analysis of Digital Communications

Answer»

The correct answer is (a) Error DETECTION

Explanation: Error detection requires much simpler DECODING equipment and much LESS REDUNDANCY than error correction.
Discussion
18.

In continuous ARQ will pullback uses _____ system.(a) Half duplex(b) Full duplex(c) Simplex(d) None of the mentionedThis question was addressed to me in my homework.This intriguing question originated from Link Budget Analysis and Error Control in section Communication Link Analysis of Digital Communications

Answer»

Right answer is (b) Full DUPLEX

For explanation: The ARQ procedure called continuous ARQ with PULLBACK REQUIRES full duplex connection.
Discussion
19.

The stop and wait ARQ needs _______ connection.(a) Half duplex(b) Full duplex(c) Simplex(d) None of the mentionedI had been asked this question in a national level competition.The question is from Link Budget Analysis and Error Control in chapter Communication Link Analysis of Digital Communications

Answer»

Correct answer is (a) Half duplex

Explanation: The stop and WAIT ARQ NEEDS half duplex system since the transmitter needs ACK for each TRANSMISSION.
Discussion
20.

Visibility is ________ to required availability.(a) Proportional(b) Inversely proportional(c) Equal(d) Not relatedI had been asked this question in an online interview.I need to ask this question from Link Budget Analysis and Error Control topic in division Communication Link Analysis of Digital Communications

Answer» RIGHT CHOICE is (b) Inversely proportional

To EXPLAIN: For a fixed LINK margin, visibility is inversely proportional to the REQUIRED availability, and for a fixed availability visibility increases monotonically with margin.
Discussion
21.

The link availability measures the percentage of time the link can be ______(a) Open(b) Closed(c) Used(d) None of the mentionedI had been asked this question by my school teacher while I was bunking the class.The above asked question is from Link Budget Analysis and Error Control topic in portion Communication Link Analysis of Digital Communications

Answer»

The correct answer is (B) Closed

For explanation: Link availability is the measure of long TERM link UTILITY STATED on an average annual basis for a given GEOGRAPHICAL location, the link availability measures the percentage of time the link can be closed.
Discussion
22.

In analog receivers, noise bandwidth is _________ signal bandwidth.(a) Lesser than(b) Greater than(c) Equal to(d) Not relatedI have been asked this question in an interview for job.The origin of the question is Link Budget Analysis and Error Control in division Communication Link Analysis of Digital Communications

Answer»

Right option is (b) Greater than

The explanation is: With ANALOG receivers, NOISE bandwidth seen by the demodulator is USUALLY greater than the signal bandwidth.
Discussion
23.

Thermal noise is generated due to(a) Lossy coupling(b) Lossless coupling(c) Lossy & Lossless coupling(d) None of the mentionedI had been asked this question in an interview for internship.Question is taken from Link Budget Analysis and Error Control in division Communication Link Analysis of Digital Communications

Answer»

The correct answer is (a) LOSSY coupling

Easy EXPLANATION: THERMAL noise occurs due to the thermal motion of ELECTRONS in all CONDUCTORS. It occurs due to lossy coupling between an antenna and the receiver.
Discussion
24.

Path loss Ls is dependent on(a) Signal power(b) Effective area(c) Wavelength(d) Antenna sizeThe question was asked by my school teacher while I was bunking the class.My doubt is from Link Budget Analysis and Error Control in division Communication Link Analysis of Digital Communications

Answer»

The CORRECT answer is (C) Wavelength

For explanation: The PATH loss is wavelength(FREQUENCY) DEPENDENT.
Discussion
25.

The beam-width becomes narrower on(a) Increasing frequency(b) Increasing antenna size(c) Increasing frequency & antenna size(d) None of the mentionedI have been asked this question during an online interview.My question is from Link Budget Analysis and Error Control topic in chapter Communication Link Analysis of Digital Communications

Answer»

Right choice is (c) Increasing FREQUENCY & ANTENNA size

For explanation: Increasing EITHER the SIGNAL frequency or antenna size results in narrower beam-width.
Discussion
26.

Antenna gain ______ as effective area increases.(a) Increases(b) Decreases(c) Remains same(d) None of the mentionedThis question was addressed to me in a national level competition.My question is from Link Budget Analysis and Error Control topic in chapter Communication Link Analysis of Digital Communications

Answer»

Correct OPTION is (a) INCREASES

Easiest EXPLANATION: Antenna GAIN increases with a decrease in wavelength increase in frequency and increase in EFFECTIVE area.
Discussion
27.

Field of view is ______ to antenna gain.(a) Proportional(b) Inversely proportional(c) Half the(d) DoubleThis question was addressed to me during an internship interview.I'd like to ask this question from Link Budget Analysis and Error Control topic in portion Communication Link Analysis of Digital Communications

Answer» CORRECT option is (b) Inversely proportional

The explanation is: The antenna field of view is the MEASURE of a solid ANGLE in which most of the field power is CONCENTRATED. It is inversely RELATED to antenna gain.
Discussion
28.

Effective radiated power ofan isotropic radiator can be given as a product of(a) Radiated power and received power(b) Effective area and physical area(c) Transmitted power and transmitting gain(d) Receiving power and receiving gainThe question was posed to me in unit test.My query is from Link Budget Analysis topic in section Communication Link Analysis of Digital Communications

Answer»

Right choice is (c) TRANSMITTED power and transmitting gain

To explain I WOULD say: An EFFECTIVE radiated power with respect to an isotropic radiator EIRP can be defined as the PRODUCT of transmitted power and the gain of the transmitting antenna.
Discussion
29.

Antenna’s efficiency is given by the ratio of(a) Effective aperture to physical aperture(b) Physical aperture to effective aperture(c) Signal power to noise power(d) LossesThe question was asked in an international level competition.This question is from Link Budget Analysis topic in section Communication Link Analysis of Digital Communications

Answer»

The correct option is (a) Effective APERTURE to physical aperture

The EXPLANATION: The larger the antenna aperture the larger is the resulting SIGNAL power density in the DESIRED DIRECTION. The ratio of effective aperture to physical aperture is the antenna’s efficiency.
Discussion
30.

According to reciprocity theorem, _____ and _____ are identical.(a) Transmitting power and receiving power(b) Transmitting gain and receiving gain(c) Effective area and physical area(d) None of the mentionedI got this question in a national level competition.The doubt is from Link Budget Analysis topic in section Communication Link Analysis of Digital Communications

Answer»

Right CHOICE is (b) TRANSMITTING gain and receiving gain

The best I can EXPLAIN: The reciprocity theorem states that for a given ANTENNA and carrier WAVELENGTH the transmitting and receiving gain are identical.
Discussion
31.

Space loss occurs due to a decrease in(a) Electric field strength(b) Efficiency(c) Phase(d) Signal powerI had been asked this question in unit test.My query is from Link Budget Analysis in portion Communication Link Analysis of Digital Communications

Answer»

Right ANSWER is (a) Electric FIELD strength

The BEST explanation: DUE to the decrease in electric field strength there will be a decrease in signal strength as a function of distance. This is called as SPACE loss.
Discussion
32.

Mechanism contributing to a reduction in efficiency is called as(a) Amplitude tapering(b) Blockage(c) Edge diffraction(d) All of the mentionedThe question was asked during an interview.My query is from Link Budget Analysis topic in portion Communication Link Analysis of Digital Communications

Answer»

Right choice is (d) All of the mentioned

The explanation: MECHANISM contributing to a reduction in efficiency is CALLED as amplitude TAPERING, SPILLOVER, edge diffraction, blockage, scattering, re-radiation and dissipative LOSS.
Discussion
33.

Antennas are used(a) As transducer(b) To focus(c) As transducer & To focus(d) None of the mentionedThe question was asked at a job interview.The query is from Link Budget Analysis in chapter Communication Link Analysis of Digital Communications

Answer»

Right answer is (C) As transducer & To focus

Easiest explanation: Antennas are used as transducer that converts ELECTRONIC SIGNALS to electromagnetic fields and vice versa. They are also used to focus the electromagnetic ENERGY in the desired direction.
Discussion
34.

Which factor adds phase noise to the signal?(a) Jitter(b) Phase fluctuations(c) Jitter & Phase fluctuations(d) None of the mentionedI got this question during a job interview.I need to ask this question from Link Budget Analysis topic in section Communication Link Analysis of Digital Communications

Answer»

The correct answer is (c) Jitter & Phase fluctuations

The EXPLANATION: When a local oscillator is used in SIGNAL MIXING, phase fluctuations and jitter ADDS phase NOISE to the signal.
Discussion
35.

Which is the primary cost for degradation of error performance?(a) Loss in signal to noise ratio(b) Signal distortion(c) Signal distortion & Loss in signal to noise ratio(d) None of the mentionedI had been asked this question in final exam.My question is based upon Link Budget Analysis topic in portion Communication Link Analysis of Digital Communications

Answer» CORRECT answer is (c) Signal DISTORTION & Loss in signal to noise ratio

For explanation I would say: There are two primary causes for the DEGRADATION of ERROR performance. They are loss in signal to noise ratio and the second is signal distortion caused by intersymbol INTERFERENCE.
Discussion
36.

Link budget can help in predicting(a) Equipment weight and size(b) Technical risk(c) Prime power requirements(d) All of the mentionedI got this question in a job interview.The query is from Link Budget Analysis topic in division Communication Link Analysis of Digital Communications

Answer»

The correct option is (d) All of the mentioned

For EXPLANATION I would say: Link budget can help to PREDICT equipment weight, size, PRIME POWER requirements, technical risk and cost. Link budget is ONE of the system manager’s useful document.
Discussion
37.

Link budget consists of calculation of(a) Useful signal power(b) Interfering noise power(c) Useful signal & Interfering noise power(d) None of the mentionedThe question was asked in an online quiz.I'd like to ask this question from Link Budget Analysis topic in division Communication Link Analysis of Digital Communications

Answer»

The CORRECT option is (c) USEFUL signal & Interfering noise power

Easy EXPLANATION: The LINK analysis and its output, the link budget consists of calculations and tabulations of useful signal power and interfering noise power at the RECEIVER.
Discussion