58 + Interview Questions in Baseband Demodulation and Detection in Digital Communications Page 1 InterviewSolution

1.	Which is the main system consideration?(a) Probability of error(b) System complexity(c) Random fading channel(d) All of the mentionedThe question was asked by my school teacher while I was bunking the class.The above asked question is from Equalization and Non Coherent Detection topic in chapter Baseband Demodulation and Detection of Digital Communications
Answer» The correct option is (d) All of the mentioned Easiest explanation: The major system CONSIDERATIONS are error PROBABILITY,complexity and RANDOM fading channel. CONSIDERING all this non coherent system is more DESIRABLE than coherent.

Discussion

2.	Which is easier to implement and is preferred?(a) Coherent system(b) Non coherent system(c) Coherent & Non coherent system(d) None of the mentionedThis question was addressed to me in an interview for internship.My question is based upon Equalization and Non Coherent Detection in portion Baseband Demodulation and Detection of Digital Communications
Answer» The correct ANSWER is (B) Non coherent system To explain: A non coherent system is DESIRABLE because there may be DIFFICULTY is establishing and maintaining a coherent reference.

Discussion

3.	Coherent PSK and non coherent orthogonal FSK have a difference of ______ in PB.(a) 1db(b) 3db(c) 4db(d) 6dbI have been asked this question during a job interview.Enquiry is from Equalization and Non Coherent Detection topic in portion Baseband Demodulation and Detection of Digital Communications
Answer» Right ANSWER is (c) 4DB The best explanation: The difference of PB is approximately 4db for the best ( coherent PSK ) and the WORST (non coherent ORTHOGONAL FSK).

Discussion

4.	The DPSK needs ________ Eb/N0 than BPSK.(a) 1db more(b) 1db less(c) 3db more(d) 3db lessThe question was posed to me during a job interview.My doubt stems from Equalization and Non Coherent Detection in portion Baseband Demodulation and Detection of Digital Communications
Answer» Right choice is (a) 1DB more Easy explanation: The DPSK SYSTEM is easier to IMPLEMENT than PSK and itneeds 1db more Eb/N0 than BPSK.

Discussion

5.	The non coherent FSK needs ________ Eb/N0 than coherent FSK.(a) 1db more(b) 1db less(c) 3db more(d) 3db lessThe question was asked in a national level competition.The doubt is from Equalization and Non Coherent Detection in chapter Baseband Demodulation and Detection of Digital Communications
Answer» The correct answer is (a) 1db more To explain: The non COHERENT RECEIVER is easier to implement. The non coherent FSK NEEDS 1db more Eb/N0 than coherent FSK.

Discussion

6.	A Gaussian distribution into the non linear envelope detector yields(a) Rayleigh distribution(b) Normal distribution(c) Poisson distribution(d) Binary distributionThe question was posed to me in class test.I want to ask this question from Equalization and Non Coherent Detection topic in portion Baseband Demodulation and Detection of Digital Communications
Answer» The CORRECT choice is (a) RAYLEIGH distribution To elaborate: The two output SIGNALS of Gaussian distribution YIELDS Rayleigh and Rician distribution.

Discussion

7.	Performance of BFSK signal is ________ than BPSK.(a) 3db worse(b) 3db better(c) 6db worse(d) 6db betterI got this question in homework.The doubt is from Equalization and Non Coherent Detection in division Baseband Demodulation and Detection of Digital Communications
Answer» RIGHT OPTION is (a) 3db worse For explanation I would say: The performance of BFSK is 3db worse than BPSK signalling, since for a given signal power, the distance squared between orthogonal vectors is a factor of two less than the distance squared between orthopodal SIGNALS.

Discussion

8.	For AWGN, the noise variance is(a) N0(b) N0/2(c) 2N0(d) N0/4I got this question during an interview.The origin of the question is Equalization and Non Coherent Detection in chapter Baseband Demodulation and Detection of Digital Communications
Answer» CORRECT ANSWER is (B) N0/2 The best explanation: The noise variance out of the CORRELATOR for AWGN is N0/2.

Discussion

9.	The disadvantage of preset equalizer is that(a) It doesnot requires initial training pulse(b) Time varying channel degrades the performance of the system(c) All of the mentioned(d) None of the mentionedThis question was posed to me in an interview for internship.This key question is from Equalization and Non Coherent Detection in division Baseband Demodulation and Detection of Digital Communications
Answer»

Discussion

10.	If the filter’s tap weight remains fixed during transmission of data, then the equalization is called as(a) Preset equalization(b) Adaptive equalization(c) Fixed equalization(d) None of the mentionedThis question was addressed to me by my school teacher while I was bunking the class.Question is taken from Equalization and Non Coherent Detection topic in portion Baseband Demodulation and Detection of Digital Communications
Answer» The correct answer is (a) Preset EQUALIZATION Easiest explanation: If the weight remains FIXED during transmission of data then the equalization is called as preset equalization. It is a SIMPLE method which consists of setting the tap weight according to some average knowledge of the CHANNEL.

Discussion

11.	Preamble is used for(a) Detect start of transmission(b) To set automatic gain control(c) To align internal clocks(d) All of the mentionedI got this question in an online quiz.This interesting question is from Equalization and Non Coherent Detection topic in division Baseband Demodulation and Detection of Digital Communications
Answer» The correct option is (d) All of the mentioned Easy explanation: The receiver uses preamble for DETECTING the START of TRANSMISSION, to set automatic GAIN control, and to ALIGN internal clocks and local oscillator with the received signal.

Discussion

12.	Equalization method which is done by tracking a slowly time varying channel response is(a) Preset equalization(b) Adaptive equalization(c) Variable equalization(d) None of the mentionedThis question was posed to me in a national level competition.This intriguing question originated from Equalization and Non Coherent Detection topic in portion Baseband Demodulation and Detection of Digital Communications
Answer» The correct option is (b) Adaptive equalization For explanation I would SAY: This method is IMPLEMENTED to perform tap weight ADJUSTMENT periodically or continually. Equalization is done by tracking a slowly varying channel RESPONSE.

Discussion

13.	The index value n, in transversal filter can be used as.(a) Time offset(b) Filter coefficient identifier(c) Time offset & Filter coefficient identifier(d) None of the mentionedThis question was addressed to me during an interview for a job.My question is taken from Equalization and Non Coherent Detection topic in division Baseband Demodulation and Detection of Digital Communications
Answer»

Discussion

14.	The over-determined set of equations can be solved using(a) Zero forcing(b) Minimum mean square error(c) Zero forcing & Minimum mean square error(d) None of the mentionedThis question was addressed to me during an interview for a job.Origin of the question is Equalization and Non Coherent Detection topic in section Baseband Demodulation and Detection of Digital Communications
Answer» RIGHT OPTION is (c) Zero forcing & Minimum mean square error For explanation: The matrix x in transversal equalizer if non square with dimensions 4N+1 and 2N+1. Such equations are called as over-determined set. This can be SOLVED by two methods called as zero forcing method and minimum mean square error method.

Discussion

15.	Pseudo noise signal has _______ and _______ SNR for the same peak transmitted power.(a) Larger, smaller(b) Smaller, larger(c) Larger, larger(d) Smaller, smallerThis question was addressed to me in a job interview.My query is from Equalization and Non Coherent Detection in section Baseband Demodulation and Detection of Digital Communications
Answer» The correct choice is (C) Larger, larger To ELABORATE: A training pulse is applied to the equalizer and CORRESPONDING impulse RESPONSE is observed. Pseudo noise is preferred as the training pulse as it has larger SNR value and larger average POWER value.

Discussion

16.	As the eye opens, ISI _______(a) Increases(b) Decreases(c) Remains the same(d) None of the mentionedThis question was addressed to me in an online quiz.My question comes from Equalization and Non Coherent Detection in division Baseband Demodulation and Detection of Digital Communications
Answer» The correct option is (B) Decreases Easiest EXPLANATION: As the eye CLOSES, ISI increases and as the eye opens ISI decreases.

Discussion

17.	The range of amplitude difference gives the value of(a) Width(b) Distortion(c) Timing jitter(d) Noise marginI got this question during an internship interview.I'd like to ask this question from Equalization and Non Coherent Detection in division Baseband Demodulation and Detection of Digital Communications
Answer» Right ANSWER is (b) DISTORTION To elaborate: In the eye PATTERN, the amplitude difference GIVES the value of distortion CAUSED by ISI.

Discussion

18.	The _______ of the opening of eye pattern indicates the time over which the sampling for detection might be performed.(a) Length(b) Width(c) X-axis value(d) Y-axis valueI got this question during an internship interview.I would like to ask this question from Equalization topic in section Baseband Demodulation and Detection of Digital Communications
Answer» The correct answer is (b) Width For explanation I would SAY: An eye pattern is a display that RESULTS from measuring a system’s response to baseband signals in a prescribed WAY. The width of the opening GIVES the time over which the sampling for DETECTION might be performed.

Discussion

19.	Range of time difference of the zero crossing gives the value of(a) Width(b) Distortion(c) Timing jitter(d) Noise marginThis question was posed to me in my homework.This key question is from Equalization topic in chapter Baseband Demodulation and Detection of Digital Communications
Answer» CORRECT option is (C) TIMING jitter To elaborate: The time difference of the zero crossing in the eye PATTERN gives the VALUE of timing jitter.

Discussion

20.	Symbol spaced has ____ sample per symbol and fractionally spaced has ___ samples per symbol.(a) One, many(b) Many, one(c) One, one(d) Many, manyThis question was addressed to me during an interview for a job.Origin of the question is Equalization in chapter Baseband Demodulation and Detection of Digital Communications
Answer» CORRECT option is (a) ONE, many Easy explanation: Predetection samples are provided only on SYMBOL boundaries. A condition in which only one sample per symbol are provided is CALLED as symbol SPACED and the condition in which multiple samples are provided per symbol is called as fractionally spaced.

Discussion

21.	Transversal equalizers are ________ and decision feedback equalizers are ______(a) Feed forward, feed back(b) Feed back, feed forward(c) Feed forward, feed forward(d) Feedback, feedbackThe question was posed to me by my school teacher while I was bunking the class.My doubt is from Equalization in chapter Baseband Demodulation and Detection of Digital Communications
Answer» The correct CHOICE is (a) Feed forward, feed back For explanation I would say: Linear devices with only feed forward elements are CALLED as transversal EQUALIZERS and non linear devices with both feed forward and feed back elements are called as DECISION feedback equalizers.

Discussion

22.	The maximum likelihood sequence estimator adjusts _______ according to _____ environment.(a) Receiver, transmitter(b) Transmitter, receiver(c) Receiver, receiver(d) None of the mentionedThe question was asked by my school teacher while I was bunking the class.This key question is from Equalization topic in portion Baseband Demodulation and Detection of Digital Communications
Answer» CORRECT option is (a) Receiver, transmitter Explanation: In MAXIMUM likelihood SEQUENCE estimator it measures the impulse response value and ADJUSTS the receiver environment according to that of the transmitter.

Discussion

23.	The filters used with the equalizer is of ______ types.(a) Feed forward(b) Feed backward(c) Feed forward and feedback(d) None of the mentionedThe question was posed to me in an online interview.This key question is from Equalization in chapter Baseband Demodulation and Detection of Digital Communications
Answer» The correct choice is (C) FEED forward and feedback Easy explanation: The filters USED with equalizers can be linear devices that CONTAIN only feed forward elements or non linear devices with both feed forward and feed back elements.

Discussion

24.	Equalization process includes(a) Maximum likelihood sequence estimation(b) Equalization with filters(c) Maximum likelihood sequence estimation & Equalization with filters(d) None of the mentionedThe question was posed to me in quiz.My doubt stems from Equalization in section Baseband Demodulation and Detection of Digital Communications
Answer» The correct choice is (C) MAXIMUM likelihood SEQUENCE ESTIMATION & Equalization with filters To elaborate: Equalization process can be divided into two major categories called as maximum likelihood sequence ESTIMATOR and equalizer with a filter.

Discussion

25.	Phase distortion occurs when(a) Phase response is function of frequency(b) Phase response is not a function of frequency(c) All of the mentioned(d) None of the mentionedThe question was asked by my college director while I was bunking the class.This key question is from Equalization in division Baseband Demodulation and Detection of Digital Communications
Answer» The CORRECT option is (B) Phase RESPONSE is not a FUNCTION of frequency Explanation: When channels phase response is not a linear function of frequency within W then phase distortion occurs.

Discussion

26.	Amplitude distortion occurs when(a) Impulse response is not constant(b) Impulse response is constant(c) Frequency transfer function is constant(d) Frequency transfer function is not constantThe question was posed to me in semester exam.My doubt is from Equalization topic in division Baseband Demodulation and Detection of Digital Communications
Answer» The correct choice is (d) Frequency TRANSFER function is not constant For explanation I WOULD say: When modulus of CHANNEL’s transfer function is not constant WITHIN W then AMPLITUDE distortion occurs.

Discussion

27.	Channel’s phase response must be a linear function of(a) Time(b) Frequency(c) Time & Frequency(d) None of the mentionedI got this question in a national level competition.I'd like to ask this question from Equalization in portion Baseband Demodulation and Detection of Digital Communications
Answer» Right choice is (b) Frequency Explanation: To achieve ideal transmission characteristics, the signal’s bandwidth must be CONSTANT and the channel’s phase RESPONSE must be a LINEAR function of frequency.

Discussion

28.	Example for antipodal bandpass signaling is(a) BPSK(b) ASK(c) FSK(d) MSKThis question was addressed to me in final exam.My doubt is from Intersymbol Interference-2 in chapter Baseband Demodulation and Detection of Digital Communications
Answer»

Discussion

29.	The impulse response of the filter is the ________ of the mirror image of the signal waveform.(a) Delayed version(b) Same version(c) Delayed & Same version(d) None of the mentionedThis question was posed to me in quiz.This question is from Intersymbol Interference-2 topic in section Baseband Demodulation and Detection of Digital Communications
Answer» Correct option is (a) DELAYED version The best EXPLANATION: The MATCHED filter’s basic PROPERTY is that the IMPULSE response of the filter is the delayed version of the mirror image of the signal waveform.

Discussion

30.	Matched filter provides _____ signal to noise ratio.(a) Maximum(b) Minimum(c) Zero(d) InfinityThe question was posed to me during an interview for a job.My question comes from Intersymbol Interference-2 topic in section Baseband Demodulation and Detection of Digital Communications
Answer» Right choice is (a) MAXIMUM Easy explanation: A matched filter is a linear filter designed to give a maximum SIGNAL to noise RATIO power at the OUTPUT.

Discussion

31.	The symbol of the probability under the tail of Gaussian pdf is called as(a) Complementary error function(b) Co error function(c) Complementary error & Co error function(d) None of the mentionedThis question was addressed to me in semester exam.This is a very interesting question from Intersymbol Interference-2 topic in portion Baseband Demodulation and Detection of Digital Communications
Answer» Right choice is (c) Complementary ERROR & Co error FUNCTION For explanation I would SAY: The co error function or complementary error function is a commonly used symbol for PROBABILITY under the tail of GAUSSIAN pdf.

Discussion

32.	Optimum threshold value is given by(a) a0+a1/2(b) a0-a1/2(c) a0/2(d) a1/2This question was posed to me in homework.Enquiry is from Intersymbol Interference-2 topic in section Baseband Demodulation and Detection of Digital Communications
Answer» Right CHOICE is (a) a0+a1/2 Explanation: The optimum THRESHOLD LEVEL VALUE for error probability REDUCTION is given by a0+a1/2.

Discussion

33.	For a M-ary signal or symbol the number of likelihood functions are(a) M(b) M+1(c) M-1(d) 2MI had been asked this question in an interview for internship.My question is based upon Intersymbol Interference-2 in portion Baseband Demodulation and Detection of Digital Communications
Answer» RIGHT OPTION is (a) M The best explanation: For a M-ary SIGNAL there will be M LIKELIHOOD functions representing M signal classes to which a received signal might belong.

Discussion

34.	An error in binary decision making occurs when the channel noise is(a) Greater than the optimum threshold level(b) Lesser than the optimum threshold level(c) Greater or Lesser than the optimum threshold level(d) None of the mentionedThe question was asked by my school teacher while I was bunking the class.This interesting question is from Intersymbol Interference-2 topic in division Baseband Demodulation and Detection of Digital Communications
Answer» CORRECT CHOICE is (c) Greater or LESSER than the optimum threshold level Easy explanation: An error will OCCUR when s1(t) or s2(t) is sent and if the CHANNEL noise is greater or lesser than the optimum threshold level.

Discussion

35.	The detector that minimizes the error probability is called as(a) Maximum likelihood detector(b) Minimum likelihood detector(c) Maximum & Minimum likelihood detector(d) None of the mentionedThe question was asked in examination.My question is based upon Intersymbol Interference-2 in chapter Baseband Demodulation and Detection of Digital Communications
Answer» Correct CHOICE is (a) MAXIMUM likelihood detector To explain: For the signals that are equally likely, the detector used to MINIMIZE the error probability is CALLED as maximum likelihood detector.

Discussion

36.	According to the rule of minimizing the error probabilities, the hypothesis should be like if the priori probabilities are ________ than the ratio of likelihoods.(a) Lesser(b) Greater(c) Equal(d) None of the mentionedThis question was addressed to me in unit test.This interesting question is from Intersymbol Interference-2 topic in division Baseband Demodulation and Detection of Digital Communications
Answer» The correct option is (a) Lesser The best I can EXPLAIN: The rule of MINIMIZING the error probabilities SHOW that the hypothesis should be LIKE if the RATIO of likelihoods should be greater than the priori probabilities.

Discussion

37.	The likelihood ratio test is done between(a) Likelihood of s1 by likelihood of s2(b) Likelihood of s2 by likelihood of s1(c) Likelihood of s1 by likelihood of s1(d) None of the mentionedI had been asked this question during an online exam.My enquiry is from Intersymbol Interference-2 topic in chapter Baseband Demodulation and Detection of Digital Communications
Answer» CORRECT answer is (a) Likelihood of S1 by likelihood of s2 The BEST explanation: The likelihood ratio is given with the help of CONDITIONAL probabilities.

Discussion

38.	Examples of double side band signals are(a) ASK(b) PSK(c) ASK & PSK(d) None of the mentionedI have been asked this question in my homework.My enquiry is from Intersymbol Interference-1 in section Baseband Demodulation and Detection of Digital Communications
Answer» Correct answer is (c) ASK & PSK The BEST EXPLANATION: ASK and PSK NEEDS TWICE the TRANSMISSION bandwidth of equivalent baseband signals. Thus these are called as double side band signals.

Discussion

39.	A pulse shaping filter should satisfy two requirements. They are(a) Should be realizable(b) Should have proper roll off factor(c) Should be realizable & have proper roll off factor(d) None of the mentionedThis question was addressed to me in a job interview.Question is taken from Intersymbol Interference-1 in portion Baseband Demodulation and Detection of Digital Communications
Answer» Correct choice is (c) Should be realizable & have proper ROLL off factor The BEST explanation: A PULSE shaping FILTER should provide the desired roll off and should be realizable, that is the impulse response needs to be truncated to a finite length.

Discussion

40.	Which value of r (roll off factor)is considered as Nyquist minimum bandwidth case?(a) 0(b) 1(c) Infinity(d) None of the mentionedThis question was addressed to me in an internship interview.I'd like to ask this question from Intersymbol Interference-1 topic in portion Baseband Demodulation and Detection of Digital Communications
Answer» The correct option is (a) 0 Easiest explanation: For the roll off factor of 0 an ideal rectangular NYQUIST pulse is obtained. This is CALLED as nyquist MINIMUM bandwidth case.

Discussion

41.	Roll off factor is the fraction of(a) Excess bandwidth and absolute bandwidth(b) Excess bandwidth and minimum nyquist bandwidth(c) Absolute bandwidth and minimum nyquist bandwidth(d) None of the mentionedI have been asked this question in an interview.I need to ask this question from Intersymbol Interference-1 in division Baseband Demodulation and Detection of Digital Communications
Answer» The CORRECT option is (b) Excess bandwidth and minimum nyquist bandwidth Easiest explanation: The roll off FACTOR is DEFINED by a fraction of excess bandwidth and the minimum nyquist BANDWITH. It ranges from 0 to 1.

Discussion

42.	The minimum nyquist bandwidth for the rectangular spectrum in raised cosine filter is(a) 2T(b) 1/2T(c) T^2(d) 2/TI got this question in an internship interview.Origin of the question is Intersymbol Interference-1 in section Baseband Demodulation and Detection of Digital Communications
Answer» Right option is (b) 1/2T Easy EXPLANATION: For raised COSINE spectrum the minimum NYQUIST BANDWIDTH is equal to 1/2T.

Discussion

43.	A nyquist pulse is the one which can be represented by _____ shaped pulse multiplied by another time function.(a) Sine(b) Cosine(c) Sinc(d) None of the mentionedThe question was asked in a job interview.My question is taken from Intersymbol Interference-1 topic in portion Baseband Demodulation and Detection of Digital Communications
Answer» Right option is (c) Sinc For EXPLANATION I would say: A nyquist FILTER is one whose frequency transfer FUNCTION can be represented by a rectangular function convolved with any real EVEN symmetric frequency function and a nyquist pulse is one whose shape can be represented by sinc function multiplied by another time function.

Discussion

44.	Examples of nyquist filters are(a) Root raised cosine filter(b) Raised cosine filter(c) Root raised & Raised cosine filter(d) None of the mentionedThis question was posed to me by my college director while I was bunking the class.The origin of the question is Intersymbol Interference-1 topic in division Baseband Demodulation and Detection of Digital Communications
Answer» The CORRECT choice is (c) Root raised & Raised COSINE filter Easiest explanation: The most popular among the CLASS of NYQUIST filters are raised cosine and root raised cosine filter.

Discussion

45.	What is symbol rate packing?(a) Maximum possible symbol transmission rate(b) Maximum possible symbol receiving rate(c) Maximum bandwidth(d) Maximum ISI value allowedThe question was asked in an international level competition.The query is from Intersymbol Interference-1 topic in chapter Baseband Demodulation and Detection of Digital Communications
Answer» Right CHOICE is (a) Maximum possible SYMBOL transmission RATE The explanation: A system with bandwidth Rs/2 can support a maximum transmission rate of Rs without ISI. Thus for ideal Nyquist filtering the maximum possible symbol transmission rate is CALLED as symbol rate packing and it is equal to 2 symbols/s/Hz.

Discussion

46.	If each pulse of the sequence to be detected is in _____ shape, the pulse can be detected without ISI.(a) Sine(b) Cosine(c) Sinc(d) None of the mentionedI had been asked this question during an online interview.This interesting question is from Intersymbol Interference-1 topic in chapter Baseband Demodulation and Detection of Digital Communications
Answer» RIGHT answer is (c) SINC To EXPLAIN I would say: The sinc shaped pulse is the ideal nyquist pulse. If each pulse in the sequence to be detected is in sinc SHAPE the PULSES can be detected without ISI.

Discussion

47.	The method in which the tail of one pulse smears into adjacent symbol interval is called as(a) Intersymbol interference(b) Interbit interference(c) Interchannel interference(d) None of the mentionedThe question was posed to me by my college director while I was bunking the class.This intriguing question comes from Intersymbol Interference-1 in portion Baseband Demodulation and Detection of Digital Communications
Answer» RIGHT option is (a) Intersymbol interference For EXPLANATION: DUE to the effect of system FILTERING the received pulse can overlap on one and another. The tail of one pulse smears into the adjacent symbol interval thereby interfering the detection process. This process is called as intersymbol interference.

Discussion

48.	Channels display multi-path due to(a) Scattering(b) Time delayed reflections(c) Diffraction(d) All of the mentionedThis question was posed to me in homework.I want to ask this question from Signals and Noises in division Baseband Demodulation and Detection of Digital Communications
Answer» The correct CHOICE is (d) All of the mentioned The best I can explain: WIRELESS wide-band channels DISPLAY multi-path due to time DELAYED reflections, diffraction and also scattering.

Discussion

49.	The channel may be affected by(a) Thermal noise(b) Interference from other signals(c) Thermal noise & Interference from other signals(d) None of the mentionedThe question was asked in my homework.Question is taken from Signals and Noises in portion Baseband Demodulation and Detection of Digital Communications
Answer» Correct answer is (C) Thermal noise & Interference from other SIGNALS Easiest EXPLANATION: A CHANNEL can be modelled as a LINEAR filter with additional noise. The noise comes from thermal noise source and also from interference from other signals.

Discussion

50.	The sample from the demodulation process consists of sample which is _______ to energy of the received symbol and _____ to noise.(a) Directly and inversely proportional(b) Inversely and directly proportional(c) Both directly proportional(d) Both inversely proportionalThe question was asked in an interview for job.I want to ask this question from Signals and Noises in section Baseband Demodulation and Detection of Digital Communications
Answer» Right choice is (a) Directly and INVERSELY proportional To EXPLAIN I would say: The output symbol of the sampler CONSISTS of sample which is directly proportional to the ENERGY of the received SIGNAL and inversely proportional to the noise.

Discussion

Explore topic-wise InterviewSolutions in .

Coherent PSK and non coherent orthogonal FSK have a difference of ______ in PB.(a) 1db(b) 3db(c) 4db(d) 6dbI have been asked this question during a job interview.Enquiry is from Equalization and Non Coherent Detection topic in portion Baseband Demodulation and Detection of Digital Communications

The DPSK needs ________ Eb/N0 than BPSK.(a) 1db more(b) 1db less(c) 3db more(d) 3db lessThe question was posed to me during a job interview.My doubt stems from Equalization and Non Coherent Detection in portion Baseband Demodulation and Detection of Digital Communications

The non coherent FSK needs ________ Eb/N0 than coherent FSK.(a) 1db more(b) 1db less(c) 3db more(d) 3db lessThe question was asked in a national level competition.The doubt is from Equalization and Non Coherent Detection in chapter Baseband Demodulation and Detection of Digital Communications

Performance of BFSK signal is ________ than BPSK.(a) 3db worse(b) 3db better(c) 6db worse(d) 6db betterI got this question in homework.The doubt is from Equalization and Non Coherent Detection in division Baseband Demodulation and Detection of Digital Communications

For AWGN, the noise variance is(a) N0(b) N0/2(c) 2N0(d) N0/4I got this question during an interview.The origin of the question is Equalization and Non Coherent Detection in chapter Baseband Demodulation and Detection of Digital Communications

As the eye opens, ISI _______(a) Increases(b) Decreases(c) Remains the same(d) None of the mentionedThis question was addressed to me in an online quiz.My question comes from Equalization and Non Coherent Detection in division Baseband Demodulation and Detection of Digital Communications

Range of time difference of the zero crossing gives the value of(a) Width(b) Distortion(c) Timing jitter(d) Noise marginThis question was posed to me in my homework.This key question is from Equalization topic in chapter Baseband Demodulation and Detection of Digital Communications

Channel’s phase response must be a linear function of(a) Time(b) Frequency(c) Time & Frequency(d) None of the mentionedI got this question in a national level competition.I'd like to ask this question from Equalization in portion Baseband Demodulation and Detection of Digital Communications

Example for antipodal bandpass signaling is(a) BPSK(b) ASK(c) FSK(d) MSKThis question was addressed to me in final exam.My doubt is from Intersymbol Interference-2 in chapter Baseband Demodulation and Detection of Digital Communications

Matched filter provides _____ signal to noise ratio.(a) Maximum(b) Minimum(c) Zero(d) InfinityThe question was posed to me during an interview for a job.My question comes from Intersymbol Interference-2 topic in section Baseband Demodulation and Detection of Digital Communications

Optimum threshold value is given by(a) a0+a1/2(b) a0-a1/2(c) a0/2(d) a1/2This question was posed to me in homework.Enquiry is from Intersymbol Interference-2 topic in section Baseband Demodulation and Detection of Digital Communications

For a M-ary signal or symbol the number of likelihood functions are(a) M(b) M+1(c) M-1(d) 2MI had been asked this question in an interview for internship.My question is based upon Intersymbol Interference-2 in portion Baseband Demodulation and Detection of Digital Communications

Examples of double side band signals are(a) ASK(b) PSK(c) ASK & PSK(d) None of the mentionedI have been asked this question in my homework.My enquiry is from Intersymbol Interference-1 in section Baseband Demodulation and Detection of Digital Communications

The minimum nyquist bandwidth for the rectangular spectrum in raised cosine filter is(a) 2T(b) 1/2T(c) T^2(d) 2/TI got this question in an internship interview.Origin of the question is Intersymbol Interference-1 in section Baseband Demodulation and Detection of Digital Communications

Channels display multi-path due to(a) Scattering(b) Time delayed reflections(c) Diffraction(d) All of the mentionedThis question was posed to me in homework.I want to ask this question from Signals and Noises in division Baseband Demodulation and Detection of Digital Communications