25 + Interview Questions in Source Coding in Digital Communications Page 1 InterviewSolution

1.	The type of noise that interferes much with high frequency transmission is(a) White(b) Flicker(c) Transit time(d) ShotThis question was addressed to me in examination.This interesting question is from Quantization topic in chapter Source Coding of Digital Communications
Answer» RIGHT option is (C) Transit TIME Easy explanation: The TYPE of noise that interferes MUCH with high frequency transmission is transit time.

Discussion

2.	Thermal noise power of a resistor depends upon(a) Its resistance value(b) Noise temperature(c) Bandwidth(d) Ambient temperatureThe question was asked in final exam.My question is taken from Quantization in division Source Coding of Digital Communications
Answer» Correct answer is (B) Noise temperature Best explanation: Thermal noise POWER of a RESISTOR DEPENDS upon noise temperature.

Discussion

3.	The probability density function of the envelope of narrow band noise is(a) Uniform(b) Gaussian(c) Rayleigh(d) RicianI have been asked this question during a job interview.I want to ask this question from Quantization in portion Source Coding of Digital Communications
Answer» Correct answer is (b) Gaussian For EXPLANATION I WOULD say: The PROBABILITY density FUNCTION of the envelope of NARROW band noise is Gaussian function.

Discussion

4.	The spectral density of white noise is(a) Exponential(b) Uniform(c) Poisson(d) GaussianI got this question by my school teacher while I was bunking the class.Question is taken from Quantization in portion Source Coding of Digital Communications
Answer» The correct option is (B) Uniform Best EXPLANATION: The spectral DENSITY of white NOISE is uniform.

Discussion

5.	Non uniform quantizer ______ distortion.(a) Increases(b) Decreases(c) Does not effect(d) None of the mentionedI had been asked this question during an online interview.My doubt stems from Quantization topic in chapter Source Coding of Digital Communications
Answer» CORRECT CHOICE is (B) Decreases Easy explanation: Distortion can be reduced by using NON uniform QUANTIZER.

Discussion

6.	Vector quantization is used in(a) Audio coding(b) Video coding(c) Speech coding(d) All of the mentionedI got this question in semester exam.Origin of the question is Quantization in portion Source Coding of Digital Communications
Answer» The CORRECT answer is (c) Speech coding To elaborate: VECTOR quantization is WIDELY used in speech coding for DIGITAL cellular systems.

Discussion

7.	The theoretical gain in zero crossing TED is greater than early late TED.(a) True(b) FalseThe question was posed to me in quiz.This interesting question is from Quantization in section Source Coding of Digital Communications
Answer»

Discussion

8.	The low pass filter at the output end of delta modulator depends on(a) Step size(b) Quantization noise(c) Bandwidth(d) None of the mentionedThe question was asked during an internship interview.My question comes from Quantization topic in division Source Coding of Digital Communications
Answer» CORRECT ANSWER is (c) Bandwidth Best explanation: The design of LOW pass filter at the OUTPUT end of DELTA modulator depends on bandwidth.

Discussion

9.	In early late timing error detection method if the bit is constant, then the slope will be(a) Close to zero(b) Close to infinity(c) Close to origin(d) None of the mentionedI have been asked this question during an internship interview.Enquiry is from Quantization topic in division Source Coding of Digital Communications
Answer» CORRECT choice is (a) Close to zero To explain: In early timing ERROR DETECTION method if the bit is constant and doesn’t CHANGE, then the slope will be close to zero.

Discussion

10.	Which helps in maintaining the step size?(a) Delta modulation(b) PCM(c) DPCM(d) Adaptive delta modulationThe question was asked in class test.The question is from Quantization in division Source Coding of Digital Communications
Answer» Correct answer is (d) Adaptive DELTA modulation To EXPLAIN: Step size if EFFECTIVELY maintained USING adaptive delta modulation.

Discussion

11.	If step size is increased _____ occurs.(a) Slope overload distortion(b) Granular noise(c) Slope overload distortion & Granular noise(d) None of the mentionedI have been asked this question in quiz.My doubt stems from Quantization topic in division Source Coding of Digital Communications
Answer» The correct answer is (b) GRANULAR noise To explain I WOULD SAY: When step size is increased to prevent SLOPE overload DISTORTION, granular noise occurs.

Discussion

12.	Prediction gain _____ for better prediction.(a) Increases(b) Decreases(c) Remains same(d) None of the mentionedThis question was addressed to me in final exam.The above asked question is from Quantization topic in chapter Source Coding of Digital Communications
Answer» CORRECT answer is (a) INCREASES The best I can EXPLAIN: Prediction GAIN increases for BETTER prediction.

Discussion

13.	1 bit quantizer is a(a) Hard limiter(b) Two level comparator(c) Hard limiter & Two level comparator(d) None of the mentionedThe question was asked in an international level competition.I would like to ask this question from Quantization topic in division Source Coding of Digital Communications
Answer» RIGHT option is (c) Hard limiter & TWO level COMPARATOR To explain I would SAY: 1 bit quantizer is ALSO called as two level comparator and also as hard limiter.

Discussion

14.	The SNR value can be increased by _____ the number of levels.(a) Increasing(b) Decreasing(c) Does not depend on(d) None of the mentionedI have been asked this question at a job interview.I need to ask this question from Quantization in section Source Coding of Digital Communications
Answer» Correct ANSWER is (a) Increasing The explanation is: The signal to noise RATIO can be INCREASED by increasing the number of LEVELS.

Discussion

15.	Delta modulation is(a) 1 bit DPCM(b) 2 bit DPCM(c) 4 bit DPCM(d) None of the mentionedThe question was asked by my school teacher while I was bunking the class.The above asked question is from Quantization topic in section Source Coding of Digital Communications
Answer» The correct OPTION is (a) 1 bit DPCM The explanation is: DELTA MODULATION is also CONSIDERED as 1 bit DPCM.

Discussion

16.	When the base of the logarithm is e, the unit of measure of information is(a) Bits(b) Bytes(c) Nats(d) None of the mentionedI got this question in an interview for job.This key question is from Quantization in section Source Coding of Digital Communications
Answer» Right answer is (c) Nats The explanation is: The UNIT of measure of information is DETERMINED BASED on the BASE of logarithm. If the base is E then the unit is nats( natural unit).

Discussion

17.	Uniform quantizer is also known as(a) Low rise type(b) Mid rise type(c) High rise type(d) None of the mentionedI got this question during an internship interview.Asked question is from Quantization in division Source Coding of Digital Communications
Answer» CORRECT choice is (B) MID rise TYPE Explanation: Uniform QUANTIZER is also known as mid rise type quantizer.

Discussion

18.	The output of an information source is(a) Random(b) Deterministic(c) Random & Deterministic(d) None of the mentionedThe question was posed to me in semester exam.My question is based upon Quantization topic in section Source Coding of Digital Communications
Answer» The CORRECT option is (a) Random The best I can EXPLAIN: The OUTPUT of any INFORMATION SOURCE is random.

Discussion

19.	The mutual information between a pair of events is(a) Positive(b) Negative(c) Zero(d) All of the mentionedI have been asked this question in semester exam.Enquiry is from Quantization topic in section Source Coding of Digital Communications
Answer» Right answer is (d) All of the mentioned To EXPLAIN: The MUTUAL information between a pair of EVENTS can be POSITIVE negative or zero.

Discussion

20.	The output of the source encoder is an analog signal.(a) True(b) FalseThe question was asked in a national level competition.My question is based upon Quantization topic in portion Source Coding of Digital Communications
Answer» The correct answer is (b) False Best explanation: The OUTPUT of the SOURCE ENCODER is a SEQUENCE of BINARY digits. The conversion of source output to digital form is done here in source encoder.

Discussion

21.	If the channel is noiseless information conveyed is ___ and if it is useless channel information conveyed is ___(a) 0,0(b) 1,1(c) 0,1(d) 1,0This question was addressed to me during an online interview.The above asked question is from Quantization topic in portion Source Coding of Digital Communications
Answer» CORRECT option is (d) 1,0 The BEST explanation: If the CHANNEL is NOISELESS information conveyed is 1 and if it is USELESS channel information conveyed is 0.

Discussion

22.	Quantization is a _____ process.(a) Few to few mapping(b) Few to many mapping(c) Many to few mapping(d) Many to many mappingThis question was posed to me in final exam.I need to ask this question from Quantization in section Source Coding of Digital Communications
Answer» The CORRECT option is (c) MANY to few MAPPING The best explanation: Quantization is a many to few mapping PROCESS.

Discussion

23.	Which conveys more information?(a) High probability event(b) Low probability event(c) High & Low probability event(d) None of the mentionedI had been asked this question in quiz.The doubt is from Quantization topic in division Source Coding of Digital Communications
Answer» Right CHOICE is (B) LOW probability event Best explanation: High probability event conveys less INFORMATION than a low probability event.

Discussion

24.	Which is a quantization process?(a) Rounding(b) Truncation(c) Rounding & Truncation(d) None of the mentionedThis question was addressed to me in an internship interview.Query is from Quantization in chapter Source Coding of Digital Communications
Answer» The correct OPTION is (c) Rounding & TRUNCATION To explain: Rounding and truncation are examples of quantization PROCESS.

Discussion

25.	Spread spectrum is used for(a) Encrypting signal(b) Hiding signal(c) Encrypting & Hiding signal(d) None of the mentionedThe question was posed to me in an online quiz.Question is taken from Quantization in division Source Coding of Digital Communications
Answer» Right choice is (C) ENCRYPTING & Hiding signal The explanation: SPREAD spectrum is used for hiding and encrypting SIGNALS.

Discussion

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The type of noise that interferes much with high frequency transmission is(a) White(b) Flicker(c) Transit time(d) ShotThis question was addressed to me in examination.This interesting question is from Quantization topic in chapter Source Coding of Digital Communications

Thermal noise power of a resistor depends upon(a) Its resistance value(b) Noise temperature(c) Bandwidth(d) Ambient temperatureThe question was asked in final exam.My question is taken from Quantization in division Source Coding of Digital Communications

The probability density function of the envelope of narrow band noise is(a) Uniform(b) Gaussian(c) Rayleigh(d) RicianI have been asked this question during a job interview.I want to ask this question from Quantization in portion Source Coding of Digital Communications

The spectral density of white noise is(a) Exponential(b) Uniform(c) Poisson(d) GaussianI got this question by my school teacher while I was bunking the class.Question is taken from Quantization in portion Source Coding of Digital Communications

Non uniform quantizer ______ distortion.(a) Increases(b) Decreases(c) Does not effect(d) None of the mentionedI had been asked this question during an online interview.My doubt stems from Quantization topic in chapter Source Coding of Digital Communications

Vector quantization is used in(a) Audio coding(b) Video coding(c) Speech coding(d) All of the mentionedI got this question in semester exam.Origin of the question is Quantization in portion Source Coding of Digital Communications

The theoretical gain in zero crossing TED is greater than early late TED.(a) True(b) FalseThe question was posed to me in quiz.This interesting question is from Quantization in section Source Coding of Digital Communications

The low pass filter at the output end of delta modulator depends on(a) Step size(b) Quantization noise(c) Bandwidth(d) None of the mentionedThe question was asked during an internship interview.My question comes from Quantization topic in division Source Coding of Digital Communications

Which helps in maintaining the step size?(a) Delta modulation(b) PCM(c) DPCM(d) Adaptive delta modulationThe question was asked in class test.The question is from Quantization in division Source Coding of Digital Communications

If step size is increased _____ occurs.(a) Slope overload distortion(b) Granular noise(c) Slope overload distortion & Granular noise(d) None of the mentionedI have been asked this question in quiz.My doubt stems from Quantization topic in division Source Coding of Digital Communications

Prediction gain _____ for better prediction.(a) Increases(b) Decreases(c) Remains same(d) None of the mentionedThis question was addressed to me in final exam.The above asked question is from Quantization topic in chapter Source Coding of Digital Communications

1 bit quantizer is a(a) Hard limiter(b) Two level comparator(c) Hard limiter & Two level comparator(d) None of the mentionedThe question was asked in an international level competition.I would like to ask this question from Quantization topic in division Source Coding of Digital Communications

The SNR value can be increased by _____ the number of levels.(a) Increasing(b) Decreasing(c) Does not depend on(d) None of the mentionedI have been asked this question at a job interview.I need to ask this question from Quantization in section Source Coding of Digital Communications

Delta modulation is(a) 1 bit DPCM(b) 2 bit DPCM(c) 4 bit DPCM(d) None of the mentionedThe question was asked by my school teacher while I was bunking the class.The above asked question is from Quantization topic in section Source Coding of Digital Communications

When the base of the logarithm is e, the unit of measure of information is(a) Bits(b) Bytes(c) Nats(d) None of the mentionedI got this question in an interview for job.This key question is from Quantization in section Source Coding of Digital Communications

Uniform quantizer is also known as(a) Low rise type(b) Mid rise type(c) High rise type(d) None of the mentionedI got this question during an internship interview.Asked question is from Quantization in division Source Coding of Digital Communications

The output of an information source is(a) Random(b) Deterministic(c) Random & Deterministic(d) None of the mentionedThe question was posed to me in semester exam.My question is based upon Quantization topic in section Source Coding of Digital Communications

The mutual information between a pair of events is(a) Positive(b) Negative(c) Zero(d) All of the mentionedI have been asked this question in semester exam.Enquiry is from Quantization topic in section Source Coding of Digital Communications

The output of the source encoder is an analog signal.(a) True(b) FalseThe question was asked in a national level competition.My question is based upon Quantization topic in portion Source Coding of Digital Communications

If the channel is noiseless information conveyed is _ and if it is useless channel information conveyed is _(a) 0,0(b) 1,1(c) 0,1(d) 1,0This question was addressed to me during an online interview.The above asked question is from Quantization topic in portion Source Coding of Digital Communications

Quantization is a _____ process.(a) Few to few mapping(b) Few to many mapping(c) Many to few mapping(d) Many to many mappingThis question was posed to me in final exam.I need to ask this question from Quantization in section Source Coding of Digital Communications

Which conveys more information?(a) High probability event(b) Low probability event(c) High & Low probability event(d) None of the mentionedI had been asked this question in quiz.The doubt is from Quantization topic in division Source Coding of Digital Communications

Which is a quantization process?(a) Rounding(b) Truncation(c) Rounding & Truncation(d) None of the mentionedThis question was addressed to me in an internship interview.Query is from Quantization in chapter Source Coding of Digital Communications

Spread spectrum is used for(a) Encrypting signal(b) Hiding signal(c) Encrypting & Hiding signal(d) None of the mentionedThe question was posed to me in an online quiz.Question is taken from Quantization in division Source Coding of Digital Communications