Explore topic-wise InterviewSolutions in .

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.

51.

Which corrects the sampling time problem in a digital system?(a) Interpolator(b) Decimator(c) Equalizer(d) FilterI got this question during an interview.My enquiry is from Digital Communication System topic in portion Signals and Spectra of Digital Communications

Answer»

Right choice is (a) Interpolator

To EXPLAIN I would say: Interpolator corrects the sampling TIME PROBLEM using DISCRETE time processing.
Discussion
52.

The equivalent temperature in a receiver design must be kept(a) Low(b) High(c) Does not affect the receiver(d) None of the mentionedThis question was posed to me in an online quiz.I'd like to ask this question from Digital Communication System topic in portion Signals and Spectra of Digital Communications

Answer» RIGHT option is (a) Low

For explanation: The equivalent temperature is the function of the receiver DESIGN and it must be ALWAYS KEPT low.
Discussion
53.

Wired channels are(a) Lossy(b) Lossless(c) Lossy & Lossless(d) None of the mentionedThe question was asked in my homework.Query is from Digital Communication System in division Signals and Spectra of Digital Communications

Answer» RIGHT OPTION is (a) LOSSY

Explanation: WIRED CHANNELS are lossy channels.
Discussion
54.

What conditions must be fulfilled in a good digital communication system?(a) High data rate(b) High fidelity(c) Low transmit power(d) All of the mentionedI had been asked this question in exam.Question is from Digital Communication System in chapter Signals and Spectra of Digital Communications

Answer»

The correct option is (d) All of the mentioned

Easy explanation: Some of the conditions which must be SATISFIED in a DIGITAL communication SYSTEM are high data rate, high fidelity, low bandwidth, low TRANSMIT POWER and low transmitter and receiver complexity.
Discussion
55.

What are the main features of a receiver?(a) Synchronization(b) Multiple parallel receiver chain(c) Synchronization & Multiple parallel receiver chain(d) None of the mentionedThis question was addressed to me during an online exam.My question is taken from Digital Communication System topic in section Signals and Spectra of Digital Communications

Answer»

The correct CHOICE is (C) Synchronization & Multiple PARALLEL receiver chain

The explanation is: The main FEATURES of a receiver which increases its complexity are synchronization of carrier, phase, and timing and multiple parallel receiver chain.
Discussion
56.

Analog to digital conversion includes(a) Sampling(b) Quantization(c) Sampling & Quantization(d) None of the mentionedI had been asked this question during an online interview.My doubt stems from Digital Communication in section Signals and Spectra of Digital Communications

Answer» RIGHT option is (C) Sampling & Quantization

Easy explanation: ANALOG to digital conversion is a two step process which INCLUDES sampling and quantization.
Discussion
57.

Digital system includes(a) Better encryption algorithm(b) Difficult data multiplexing(c) All of the mentioned(d) None of the mentionedI got this question during an interview for a job.This interesting question is from Digital Communication in portion Signals and Spectra of Digital Communications

Answer»

Correct choice is (a) Better encryption ALGORITHM

Explanation: DIGITAL SYSTEM has an ADVANTAGE of better encryption algorithm, easier data multiplexing and more reliability.
Discussion
58.

Synchronization available in digital communication are(a) Symbol synchronization(b) Frame synchronization(c) Carrier synchronization(d) All of the mentionedThe question was posed to me in examination.This interesting question is from Digital Communication topic in portion Signals and Spectra of Digital Communications

Answer»

The correct ANSWER is (d) All of the mentioned

The explanation: The synchronization TECHNIQUES AVAILABLE in digital communication are SYMBOL synchronization, frame synchronization and CARRIER synchronization.
Discussion
59.

The attenuation level in bounded power spectral density is(a) 35(b) 50(c) 35 & 50(d) none of the mentionedI had been asked this question in an international level competition.This key question is from Digital Communication topic in division Signals and Spectra of Digital Communications

Answer» CORRECT choice is (c) 35 & 50

For explanation: Bounded power spectral DENSITY is the BANDWIDTH outside which the spectrum must have FALLEN to a stated level below that FOUND at the band center.
Discussion
60.

Which system uses digital transmission?(a) ISDN(b) LANs(c) ISDN & LANs(d) None of the mentionedThe question was posed to me in examination.This is a very interesting question from Digital Communication topic in portion Signals and Spectra of Digital Communications

Answer» RIGHT CHOICE is (c) ISDN & LANs

The explanation is: Though the signal type is analog or DIGITAL, the transmission takes place in the digital domain in ISDN and LANs.
Discussion
61.

What are the disadvantages of digital communication?(a) Needs more bandwidth(b) Is more complex(c) Needs more bandwidth & Is more complex(d) None of the mentionedThis question was addressed to me during an internship interview.Origin of the question is Digital Communication topic in section Signals and Spectra of Digital Communications

Answer»

The CORRECT answer is (c) NEEDS more bandwidth & Is more complex

To explain: Digital communication needs more bandwidth, has HIGHER complexity and LITTLE PERFORMANCE degradation occurs during analog to digital conversion and vice versa.
Discussion
62.

The interval of frequencies outside which the spectrum is zero is called as ________(a) null to null bandwidth(b) normalized bandwidth(c) absolute bandwidth(d) none of the mentionedI have been asked this question in an online interview.Asked question is from Digital Communication topic in division Signals and Spectra of Digital Communications

Answer»

Correct ANSWER is (c) absolute bandwidth

The explanation is: The measure of frequencies outside which spectrum is ZERO is CALLED as absolute bandwidth. It is USUALLY infinite.
Discussion
63.

Examples of digital communication are(a) ISDN(b) Modems(c) Classical telephony(d) All of the mentionedThe question was posed to me by my school principal while I was bunking the class.This intriguing question originated from Digital Communication in division Signals and Spectra of Digital Communications

Answer»

The correct option is (d) All of the mentioned

Explanation: Some of the examples of DIGITAL communication systems are CLASSICAL telephony, ISDN, Modems, LANs, PCM TDM ETC.
Discussion
64.

Digital communication is _______ to environmental changes?(a) Less sensitive(b) More sensitive(c) Does not depend(d) None of the mentionedI have been asked this question in examination.I would like to ask this question from Digital Communication in section Signals and Spectra of Digital Communications

Answer»

Correct choice is (a) Less sensitive

Best EXPLANATION: Digital communication is less sensitive to ENVIRONMENTAL CHANGES like TEMPERATURE etc.
Discussion
65.

What is necessary for digital communication?(a) Precision timing(b) Frame synchronization(c) Character synchronization(d) All of the mentionedThe question was asked during an internship interview.This question is from Digital Communication in section Signals and Spectra of Digital Communications

Answer»

The CORRECT OPTION is (d) All of the mentioned

Explanation: Bit, character, FRAME synchronization and PRECISION timing is necessary for digital COMMUNICATION. This is considered as a disadvantage of digital communication.
Discussion
66.

Advantages of digital communication are(a) Easy multiplexing(b) Easy processing(c) Reliable(d) All of the mentionedThis question was posed to me in a national level competition.This question is from Digital Communication topic in division Signals and Spectra of Digital Communications

Answer»

The CORRECT OPTION is (d) All of the mentioned

The explanation is: Digital COMMUNICATION is a very RELIABLE communication. It is easy for multiplexing, easy for SIGNALLING and processing etc.
Discussion
67.

Thermal noise is a wide sense stationary process.(a) True(b) FalseThis question was posed to me in exam.The above asked question is from Noise topic in portion Signals and Spectra of Digital Communications

Answer»

The CORRECT answer is (a) True

Easiest explanation: Thermal noise is modeled as a wide SENSE stationary stochastic PROCESS.
Discussion
68.

Matched filter is(a) Linear(b) Non linear(c) Linear & Non linear(d) None of the mentionedI got this question in an interview for job.My question is taken from Noise topic in portion Signals and Spectra of Digital Communications

Answer»

Right OPTION is (a) LINEAR

To EXPLAIN I would say: MATCHED FILTER is a linear filter.
Discussion
69.

The maximum likelihood function is(a) Positive(b) Negative(c) Any of the mentioned(d) None of the mentionedThe question was posed to me by my college professor while I was bunking the class.Question is from Noise in section Signals and Spectra of Digital Communications

Answer»

The correct CHOICE is (a) POSITIVE

The best EXPLANATION: The maximum likelihood FUNCTION is always positive.
Discussion
70.

Which consists of less ISI?(a) Nyquist filter(b) Raised cosine filter(c) Nyquist & Raised cosine filter(d) None of the mentionedThe question was posed to me during an internship interview.I'd like to ask this question from Noise in division Signals and Spectra of Digital Communications

Answer»

Right choice is (B) RAISED cosine FILTER

The best EXPLANATION: Raised cosine filter results in less ISI than NYQUIST filter.
Discussion
71.

Matched filtering operation includes(a) Spectral phase matching(b) Spectral amplitude matching(c) Spectral phase &amplitude matching(d) None of the mentionedThis question was posed to me in an interview for internship.This interesting question is from Noise topic in section Signals and Spectra of Digital Communications

Answer»

The correct answer is (C) SPECTRAL phase &AMPLITUDE matching

The EXPLANATION is: MATCHED filtering includes two operations – spectral amplitude matching and spectral phase matching.
Discussion
72.

Capacity of the channel can be increased by reducing in band noise power.(a) True(b) FalseThe question was posed to me in quiz.Asked question is from Noise in portion Signals and Spectra of Digital Communications

Answer» CORRECT option is (a) True

The best I can explain: CAPACITY of a channel can be INCREASED by REDUCING the in band NOISE power.
Discussion
73.

Capacity of a channel can be increased by(a) Increasing channel bandwidth(b) Increasing signal power(c) Increasing channel bandwidth &signal power(d) None of the mentionedThe question was posed to me in homework.The origin of the question is Noise in section Signals and Spectra of Digital Communications

Answer»

Correct answer is (c) Increasing channel bandwidth &signal power

Easy EXPLANATION: Capacity of a channel can be INCREASED by increasing channel bandwidth and also by increasing signal power.
Discussion
74.

Thermal noise is(a) Energy signal(b) Power signal(c) Energy & Power signal(d) None of the mentionedThis question was addressed to me at a job interview.Question is from Noise in chapter Signals and Spectra of Digital Communications

Answer»

The correct ANSWER is (b) Power SIGNAL

Best explanation: THERMAL NOISE is considered as power signal as it has infinite ENERGY.
Discussion
75.

Noise has(a) Infinite energy(b) Infinite power(c) Infinite energy & power(d) None of the mentionedI had been asked this question by my school teacher while I was bunking the class.My question is taken from Noise in portion Signals and Spectra of Digital Communications

Answer»

Correct CHOICE is (a) INFINITE energy

For EXPLANATION I would SAY: NOISE has infinite energy signal.
Discussion
76.

Which noise is useful for dithering?(a) White noise(b) Pink noise(c) Brown noise(d) None of the mentionedI have been asked this question in exam.The question is from Noise in chapter Signals and Spectra of Digital Communications

Answer»

The correct ANSWER is (C) Brown noise

The explanation: Brown noise is SOMETIMES useful for dithering.
Discussion
77.

Shot noise is(a) Stochastic process(b) Poisson process(c) Stochastic & Poisson process(d) None of the mentionedThe question was asked in an online quiz.This is a very interesting question from Noise in section Signals and Spectra of Digital Communications

Answer»

The CORRECT choice is (b) Poisson process

Explanation: SHOT NOISE is a Poisson process.
Discussion
78.

Shot noise is avoidable when current is(a) Zero(b) One(c) Infinity(d) None of the mentionedThe question was posed to me in an interview for job.This question is from Noise in chapter Signals and Spectra of Digital Communications

Answer»

The correct choice is (a) Zero

The explanation: SHOT NOISE is AVOIDABLE only when the current is zero.
Discussion
79.

Flicker noise is called as(a) White noise(b) Pink noise(c) Brown noise(d) None of the mentionedThis question was posed to me in an internship interview.This interesting question is from Noise in chapter Signals and Spectra of Digital Communications

Answer»

Right option is (b) PINK NOISE

For EXPLANATION: Flicker noise is called as pink noise.
Discussion
80.

Which occurs due to equilibrium fluctuations?(a) Thermal noise(b) Johnson noise(c) Thermal & Johnson noise(d) None of the mentionedThis question was addressed to me by my school principal while I was bunking the class.This intriguing question comes from Noise topic in portion Signals and Spectra of Digital Communications

Answer»

The correct choice is (c) Thermal & Johnson noise

To explain I would say: Thermal noise OCCURS DUE to EQUILIBRIUM fluctuations. This noise is ALSO called as Johnson noise.
Discussion
81.

Which has the same power spectral density?(a) White noise(b) Brown noise(c) White & Brown noise(d) None of the mentionedThe question was posed to me in an online interview.My question is from Noise topic in chapter Signals and Spectra of Digital Communications

Answer»
Discussion
82.

Shot noise is produced by(a) Electrons(b) Photons(c) Electrons & Photons(d) None of the mentionedI had been asked this question in an interview for internship.This is a very interesting question from Noise topic in division Signals and Spectra of Digital Communications

Answer»

Right ANSWER is (c) Electrons & Photons

For explanation I WOULD say: Shot noise occurs DUE to particle like the BEHAVIOUR of ELECTRON and photon.
Discussion
83.

Two functions are called as orthogonal if on integrating the product we get(a) One(b) Zero(c) Infinity(d) None of the mentionedThis question was posed to me during an internship interview.I'm obligated to ask this question of Noise in chapter Signals and Spectra of Digital Communications

Answer»

Right option is (B) ZERO

To elaborate: TWO functions are CALLED as orthogonal if the integral value of integrating the product is zero.
Discussion
84.

Eigen functions are not orthogonal.(a) True(b) FalseI got this question in my homework.Question is taken from Noise topic in section Signals and Spectra of Digital Communications

Answer»

Correct answer is (b) False

The explanation is: An IMPORTANT property of EIGEN FUNCTION is that they are orthogonal.
Discussion
85.

SQNR can be improved by _______ sampling rate.(a) Increasing(b) Decreasing(c) Does not depend(d) None of the mentionedThe question was asked during an interview for a job.My doubt stems from Noise topic in section Signals and Spectra of Digital Communications

Answer»

The correct CHOICE is (a) Increasing

Easiest EXPLANATION: SQNR can be improved by increasing the sampling rate.
Discussion
86.

Which offers better SQNR?(a) Delta modulation(b) PCM(c) Delta modulation & PCM(d) None of the mentionedThis question was posed to me in final exam.The above asked question is from Noise topic in portion Signals and Spectra of Digital Communications

Answer»

The correct choice is (B) PCM

For explanation I WOULD say: PCM offers better SQNR than DELTA modulation.
Discussion
87.

The measure of the width of the main lobe is called as ________(a) Null to null bandwidth(b) Half power bandwidth(c) Normalized bandwidth(d) Absolute bandwidthThis question was addressed to me during an interview.I want to ask this question from Baseband Systems and Signal Transmission through Linear Systems in chapter Signals and Spectra of Digital Communications

Answer»

The CORRECT ANSWER is (a) Null to null BANDWIDTH

Easy explanation: The main lobe consists of the MAXIMUM signal power. The measure of the width of the main lobe is called as null to null bandwidth.
Discussion
88.

Which filter has maximum flatness?(a) Chebyshev filter(b) Butter-worth filter(c) High pass filter(d) Normalized filterI got this question during an interview for a job.Asked question is from Baseband Systems and Signal Transmission through Linear Systems topic in portion Signals and Spectra of Digital Communications

Answer»
Discussion
89.

The ratio of the filter bandwidth at -60db and -6db amplitude response point is called as _____(a) Half point factor(b) Normalized factor(c) Shape factor(d) None of the mentionedThe question was posed to me in my homework.My enquiry is from Baseband Systems and Signal Transmission through Linear Systems in portion Signals and Spectra of Digital Communications

Answer»

Right choice is (c) Shape FACTOR

Explanation: Shape factor is a measure of how WELL realizable filter APPROXIMATES to ideal filter. It is the ratio of filter bandwidths -60db and -6DB amplitude POINTS.
Discussion
90.

The point at which the output signal power has fallen to 0.707 of its peak value is called as _____(a) 3db point(b) Half power point(c) 3db & Half power point(d) None of the mentionedI got this question in semester exam.I would like to ask this question from Baseband Systems and Signal Transmission through Linear Systems topic in portion Signals and Spectra of Digital Communications

Answer»

Right choice is (c) 3DB & HALF power point

For EXPLANATION: The frequency at which the OUTPUT signal power falls to half the peak value is called as half power point or 3db point.
Discussion
91.

As the order of the filter increases, the cost ______ and complexity ______(a) Increases, increases(b) Increases, decreases(c) Decreases, increases(d) Decreases, decreasesI had been asked this question in an interview for internship.This intriguing question originated from Baseband Systems and Signal Transmission through Linear Systems topic in division Signals and Spectra of Digital Communications

Answer»

The CORRECT choice is (a) Increases, increases

The best I can explain: According to the design of the filter as the order increases the complexity and COST of the filter ALSO increases.
Discussion
92.

What are the characteristics of an ideal transmission line?(a) Different amplitude(b) No distortion(c) Time delay(d) All of the mentionedThis question was posed to me in an internship interview.I want to ask this question from Baseband Systems and Signal Transmission through Linear Systems in section Signals and Spectra of Digital Communications

Answer»

Correct answer is (d) All of the mentioned

For EXPLANATION: The output from the ideal transmission LINE has some time delay DIFFERENT AMPLITUDE but it should not have distortion it should have the same shape as the input.
Discussion
93.

Find the 32-ary waveform for the word ‘HAPPY’.(a) 280856(b) 658082(c) 288056(d) None of the mentionedThis question was addressed to me in a job interview.My question is from Baseband Systems and Signal Transmission through Linear Systems in chapter Signals and Spectra of Digital Communications

Answer»

The correct option is (a) 280856

To EXPLAIN: “HAPPY”

 ASCII value: H-000100; A-100000; P-000010; P-000010; Y-100110

 32-ary symbols: 2 8 0 8 5 6.
Discussion
94.

Find the 32-ary waveform for the word ‘THINK’.(a) 514172520(b) 202517415(c) 541172520(d) None of the mentionedI had been asked this question during an internship interview.This interesting question is from Baseband Systems and Signal Transmission through Linear Systems in section Signals and Spectra of Digital Communications

Answer» CORRECT choice is (a) 514172520

Best explanation: “THINK”

 ASCII value: T-001010; H-000100; I-100100; N-011100; K-110100

 32-ary symbols(SPLIT into 5 bits): 5 1 4 17 25 20.
Discussion
95.

Find the 8-ary waveform for the word ‘HAPPY’.(a) 4040020246(b) 0440020246(c) 6420200440(d) None of the mentionedThis question was posed to me during an internship interview.My doubt is from Baseband Systems and Signal Transmission through Linear Systems topic in portion Signals and Spectra of Digital Communications

Answer»

Right answer is (b) 0440020246

The explanation: “HAPPY”

 ASCII value: H-000100; A-100000; P-000010; P-000010; Y-100110

 8-ary SYMBOLS: 0 4 4 0 0 2 0 2 4 6.
Discussion
96.

Perform the bit stream partitioning and find the 8-ary waveform for the word ‘THINK’.(a) 1204443464(b) 4643444021(c) 1240443464(d) none of the mentionedThis question was posed to me by my school teacher while I was bunking the class.Enquiry is from Baseband Systems and Signal Transmission through Linear Systems topic in section Signals and Spectra of Digital Communications

Answer»

The correct answer is (a) 1204443464

Explanation: “THINK”

ASCII value: T-001010 ; H-000100; I-100100; N-011100; K-110100

 8-ary symbols(SPLIT into 3 BITS): 1 2 0 4 4 4 3 4 6 4.
Discussion
97.

For the number of bits, k=1 and number of symbols, M=2 the system is called as(a) Unary(b) Binary(c) Quarternary(d) None of the mentionedI got this question in an interview for internship.Asked question is from Baseband Systems and Signal Transmission through Linear Systems topic in portion Signals and Spectra of Digital Communications

Answer»

Right answer is (b) BINARY

The explanation is: For K number of bits, the number of SYMBOLS are M=2^k. For k=1 and M=2 the system is called as binary CODING.
Discussion
98.

The process that transforms text into binary digits is called as _______(a) Binary coding(b) Data coding(c) Character coding(d) SamplingI got this question in class test.The query is from Baseband Systems and Signal Transmission through Linear Systems in portion Signals and Spectra of Digital Communications

Answer»

Right ANSWER is (c) CHARACTER CODING

To EXPLAIN I would SAY: According to the definition the process of converting textual data to binary digits is called as character coding.
Discussion
99.

White noise has _____ mean and ______ variance.(a) Zero and zero(b) Finite and zero(c) Zero and finite(d) One and zeroI got this question in an internship interview.The above asked question is from Random Signals topic in portion Signals and Spectra of Digital Communications

Answer» RIGHT option is (C) Zero and finite

To explain: WHITE NOISE is a zero mean function with infinite AVERAGE power, finite variance and infinite bandwidth.
Discussion
100.

Analog information is converted to digital data using(a) Sampling(b) Quantization(c) Coding(d) All of the mentionedI got this question during an online exam.My enquiry is from Baseband Systems and Signal Transmission through Linear Systems topic in section Signals and Spectra of Digital Communications

Answer» CORRECT option is (d) All of the mentioned

Best explanation: Textual information, analog information and DIGITAL information undergoes different PROCESSES before converting to binary or digital data. The method USED for converting analog information are the given METHODS.
Discussion