34 + Interview Questions in Phase Locked Loop & Pulse Modulation in Analog Communications Page 1 InterviewSolution

1.	An antenna is adjusted by adjusting the two “look angles” called _________(a) coverage and elevation(b) declination and elevation(c) azimuth and declination(d) azimuth and elevationThe question was posed to me in exam.My enquiry is from Phase Comparator in chapter Phase Locked Loop & Pulse Modulation of Analog Communications
Answer» Right choice is (d) AZIMUTH and elevation The BEST I can explain: Azimuth and Elevation are two LOOK ANGLES of any antenna. So any antenna can be adjusted by adjusting these two angles properly.

Discussion

2.	The velocity required to stay in orbit is ________(a) constant(b) infinite(c) lower close to the earth than far from the earth(d) higher close to the earth than far from the earthThis question was posed to me in unit test.This intriguing question originated from Phase Comparator in section Phase Locked Loop & Pulse Modulation of Analog Communications
Answer» The correct choice is (d) HIGHER close to the EARTH than far from the earth Explanation: The velocity in orbit must be higher close to the earth than far from the earth. Then only COMPONENTS can STAY in orbit.

Discussion

3.	PCS stands for ________(a) Portable Control Service(b) Personal Communication Systems(c) Personal Control Signal(d) Portable Communication SystemsI got this question in semester exam.The query is from Phase Comparator in chapter Phase Locked Loop & Pulse Modulation of Analog Communications
Answer» The correct OPTION is (b) PERSONAL Communication Systems Easy explanation: PCs stands for Personal Communication Systems. It is a wireless phone service SIMILAR to cellular service but emphasizing on personal service and extending MOBILITY.

Discussion

4.	What is the full form of MIN?(a) Multistage Interconnection Network(b) Mobile Identification Number(c) Maximum In-band Noise(d) Minimum In-band NoiseI got this question in an interview for job.My query is from Phase Comparator in section Phase Locked Loop & Pulse Modulation of Analog Communications
Answer» The CORRECT OPTION is (b) Mobile Identification Number For explanation: MIN stands for Mobile Identification Number. It refers to the 10 digit unique number that a wireless carrier uses to identify a mobile phone.

Discussion

5.	Which term is used for voice channels, in GSM?(a) traffic channels(b) noise channels(c) receiver channels(d) transmitter channelsI had been asked this question during an interview.Question is from Phase Comparator in portion Phase Locked Loop & Pulse Modulation of Analog Communications
Answer» CORRECT answer is (a) traffic CHANNELS Easiest explanation: Traffic channel is the term USED for VOICE channels, in GSM.

Discussion

6.	Pagers use _________(a) VHF band(b) UHF band(c) Both VHF and UHF bands(d) HF bandI had been asked this question in homework.I would like to ask this question from Phase Comparator topic in chapter Phase Locked Loop & Pulse Modulation of Analog Communications
Answer» Right ANSWER is (C) Both VHF and UHF bands The EXPLANATION: A pager is a telecommunication DEVICE that RECEIVES alert signals and short messages. It can use both UHF and VHF band.

Discussion

7.	What is the approximate IEEE specification covering wireless LANs?(a) 802.13(b) 802.12(c) 802.11(d) 802.10The question was posed to me by my college director while I was bunking the class.My question is taken from Phase Comparator in section Phase Locked Loop & Pulse Modulation of Analog Communications
Answer» Right ANSWER is (c) 802.11 For explanation: 802.11 is the approximate IEEE specification for COVERING wireless LANS. LAN stands for Local Area Network, which connects multiple DEVICES sharing a common network or being connected to the same server.

Discussion

8.	TDD stands for _________(a) Time Division Duplex(b) Time Delayed Duplex(c) Telecommunication Display Device(d) Time Definite DeliveryI had been asked this question in a job interview.My question is taken from Phase Comparator topic in portion Phase Locked Loop & Pulse Modulation of Analog Communications
Answer» The correct answer is (a) TIME DIVISION DUPLEX Explanation: TDD stands for Time Division Duplex. It refers to duplex communication links where uplink is separated from downlink. They are separated by allocating them DIFFERENT time slots in the same frequency BAND.

Discussion

9.	A Bluetooth “piconet” has ________(a) 1 node(b) 2 nodes(c) 2 to 8 nodes(d) 2 to 16 nodesI got this question during an interview.Origin of the question is Bandwidth Requirement for PAM Transition topic in division Phase Locked Loop & Pulse Modulation of Analog Communications
Answer» The correct choice is (c) 2 to 8 NODES To explain: Bluetooth is wireless technology. It is used for exchanging data over SHORT distances. It usually uses frequency hopping. In frequency hopping, the transmitter changes the frequency with respect to a certain hopping pattern. A Bluetooth piconet has 2 to 8 nodes.

Discussion

10.	POCSAG stands for ________(a) Post Office Code Standardization Advisory Group(b) Post Office Common Standardization Advisory Group(c) Pager Office Code Standardization Advisory Group(d) Pager Office Common Standardization Advisory GroupThis question was posed to me in examination.This intriguing question comes from Bandwidth Requirement for PAM Transition in chapter Phase Locked Loop & Pulse Modulation of Analog Communications
Answer» Correct answer is (a) POST Office Code Standardization Advisory Group For explanation I would say: POCSAG stands for Post Office Code Standardization Advisory Group. It formulates a paging protocol, known as POCSAG protocol. This protocol is asynchronous in nature and is used to DELIVER data to PAGERS.

Discussion

11.	Who invented the technology CDMA?(a) Qualcomm(b) Bell Labs(c) SAP Labs(d) AT&TThis question was addressed to me in an internship interview.The above asked question is from Bandwidth Requirement for PAM Transition in division Phase Locked Loop & Pulse Modulation of Analog Communications
Answer» Correct option is (a) Qualcomm Easiest explanation: CDMA STANDS for CODE Division MULTIPLE Access. CDMA was invented by Qualcomm. CDMA is a channel access method USED by various radio communication technologies. It is a kind of multiplexing where various signals uses the same transmission channel in a more optimized way.

Discussion

12.	AMPS was designed for POTS only.(a) True(b) FalseThis question was addressed to me by my school principal while I was bunking the class.My enquiry is from Bandwidth Requirement for PAM Transition topic in section Phase Locked Loop & Pulse Modulation of Analog Communications
Answer» Right answer is (B) False The BEST EXPLANATION: AMPS (Advanced Mobile Phone Service) was designed for POTS (Plain Old Telephone Service) as well as for voice. It was also designed for the use built into an automobile.

Discussion

13.	What is the full form of MTSO?(a) Minimum Transmitted Signal Output(b) Maximum Transmitted Signal Output(c) Mobile Telephone Switching Office(d) Mobile Telephone Signal OfficeThis question was addressed to me in unit test.I need to ask this question from Bandwidth Requirement for PAM Transition in portion Phase Locked Loop & Pulse Modulation of Analog Communications
Answer» The correct option is (c) Mobile TELEPHONE SWITCHING Office To explain I would say: MTSO STANDS for Mobile Telephone Switching Office. It contains the switching EQUIPMENT for routing mobile phone calls. It is a mobile version of PSTN (Public Switched Telephone Network).

Discussion

14.	AMPS stands for ________(a) American Mobile Phone System(b) Advanced Mobile Phone Service(c) American Mobile Phone Service(d) Advanced Mobile Phone SystemThe question was asked during an internship interview.Question is from Bandwidth Requirement for PAM Transition topic in section Phase Locked Loop & Pulse Modulation of Analog Communications
Answer» The correct ANSWER is (b) Advanced Mobile Phone Service The explanation is: AMPS stands for Advanced Mobile Phone Service. It is a STANDARD system for analog signal CELLULAR TELEPHONE service in the United States and in other countries. It is based on the electromagnetic radiation spectrum stated by FCC (Federal Communications COMMISSION).

Discussion

15.	“Station-keeping” refers to ___________(a) antenna maintenance(b) power level adjustments(c) orbital adjustments(d) range of frequenciesThis question was posed to me in my homework.Asked question is from Bandwidth Requirement for PAM Transition topic in section Phase Locked Loop & Pulse Modulation of Analog Communications
Answer» The CORRECT CHOICE is (c) orbital adjustments Easiest EXPLANATION: Station KEEPING refers to the orbital adjustments, whereas Bandwidth refers to RANGE of frequencies.

Discussion

16.	The area on the earth that is covered by a satellite is called __________(a) plate(b) footprint(c) downlink(d) earth stationThe question was asked during an online exam.Asked question is from Bandwidth Requirement for PAM Transition topic in chapter Phase Locked Loop & Pulse Modulation of Analog Communications
Answer» CORRECT answer is (b) footprint Explanation: Footprint refers to the AREA covered by a satellite on earth. Transmission from earth to satellite is CALLED uplink and transmission from satellite to earth is called DOWNLINK. Earth STATION is used to deliver signals obtained from satellites.

Discussion

17.	Fiber-optic cable can be used to connect a transmitter to an antenna.(a) True(b) FalseThis question was posed to me during an internship interview.My question is taken from Noise in Pulse Modulated System topic in section Phase Locked Loop & Pulse Modulation of Analog Communications
Answer» Right option is (b) False The explanation is: A fiber-optic cable consists of a BUNDLE of glass THREADS, each of which is capable of transmitting messages. Fiber-optic cable cannot be USED to connect a transmitter with an antenna. An antenna is a collection of conductors is connected electrically to the transmitter.

Discussion

18.	The loss in single-mode fiber optic cable due to the glass is about ________(a) 40 dB per km(b) 0.4 dB per km(c) zero(d) 100 dB per kmThe question was posed to me in quiz.Enquiry is from Noise in Pulse Modulated System in portion Phase Locked Loop & Pulse Modulation of Analog Communications
Answer» Correct choice is (b) 0.4 dB per km The explanation: A duplex arrangement is a cordless telephone that uses separate frequencies for TRANSMISSION in base and portable units. In duplex COMMUNICATION, SENDER and receiver can INTERACT simultaneously while in half-duplex, sender and receiver communicates one at a TIME.

Discussion

19.	Scattering causes _________(a) refraction(b) loss(c) dispersion(d) reflectionThis question was addressed to me in exam.Asked question is from Noise in Pulse Modulated System in division Phase Locked Loop & Pulse Modulation of Analog Communications
Answer» CORRECT ANSWER is (b) loss To explain: In scattering, particles are forced to deviate from a straight TRAJECTORY due to non-uniformities in the medium. Thus, it causes loss of DATA.

Discussion

20.	The loss in single-mode fiber optic cable due to the splice is about ________(a) 0.2 dB per km(b) 0.02 dB per km(c) 0.0002 dB per km(d) 2 dB per kmThis question was addressed to me during an internship interview.This key question is from Noise in Pulse Modulated System in chapter Phase Locked Loop & Pulse Modulation of Analog Communications
Answer» RIGHT answer is (B) 0.02 DB per km For explanation: A fiber-optic CABLE CONSIST of a bundle of glass threads, each of which is capable of transmitting messages. The loss in single-mode fiber optic cable due to the splice is about 0.02 dB per km. In single mode fiber optical cable, only a single light ray is transmitted.

Discussion

21.	The loss in single-mode fiber optic cable due to the connector is about ________(a) 0.2 dB per km(b) 0.02 dB per km(c) 0.0002 dB per km(d) 2 dB per kmThe question was posed to me in unit test.Question is from Noise in Pulse Modulated System in portion Phase Locked Loop & Pulse Modulation of Analog Communications
Answer» Correct choice is (a) 0.2 dB per km Easy explanation: A fiber-optic cable consist of a bundle of glass THREADS, each of which is CAPABLE of transmitting messages. The LOSS in single-mode fiber optic cable due to the CONNECTOR is about 0.2 dB per km. In single mode fiber optical cable, only a single light ray is TRANSMITTED.

Discussion

22.	What is the full form of FITL ________(a) Fiber Input Timing Loss(b) Fibre Impedance To The Loop(c) Fiber Input Timing Loop(d) Fiber In The LoopI have been asked this question in examination.This interesting question is from Noise in Pulse Modulated System in portion Phase Locked Loop & Pulse Modulation of Analog Communications
Answer» Correct ANSWER is (d) Fiber In The LOOP For explanation: FITL stands for Fiber In The Loop. It is a system used to upgrade PSTN (Public Switched TELEPHONE NETWORK) network Local loop. PSTN consists of all circuit-switched telephone in the whole world.

Discussion

23.	Adding bits to synchronize one digital signal to another is called _________(a) WDM(b) TDM(c) Bit stuffing(d) Bit synchronizationI had been asked this question in an internship interview.Question is taken from Noise in Pulse Modulated System in portion Phase Locked Loop & Pulse Modulation of Analog Communications
Answer» Right OPTION is (c) Bit stuffing Easy explanation: Bit stuffing is the addition of bits for SYNCHRONIZATION of one digital SIGNAL to another. It is MAINLY used in the TRANSMISSION process of the network and communication protocols.

Discussion

24.	What is used in Hartley oscillator?(a) a piezoelectric crystal(b) two resistor divider(c) a two-capacitor divider(d) a tapped inductorThis question was addressed to me in semester exam.I need to ask this question from PWM in chapter Phase Locked Loop & Pulse Modulation of Analog Communications
Answer» Correct answer is (d) a tapped inductor To explain I would say: In HARTLEY oscillator, the oscillation frequency is determined by a tuned circuit consisting of capacitors and INDUCTORS. Thus, it is an LC oscillator whose frequency can be varied. Hartley oscillator was INVENTED in 1915.

Discussion

25.	What is represented by “Figure Of Merit”?(a) how much noise is in the channel(b) how much noise is in the communication system(c) how much noise an amplifier adds to the signal(d) signal to noise ratio in dBI have been asked this question during an interview for a job.Asked question is from Noise in Pulse Modulated System in section Phase Locked Loop & Pulse Modulation of Analog Communications
Answer» CORRECT OPTION is (c) how much noise an amplifier adds to the signal Easy explanation: Figure Of Merit is a MEASURE of efficiency or effectiveness. It BASICALLY represents that how much noise is being added by an amplifier to the signal. HOWEVER, the signal to noise ratio is the measure of the amount of signal present with respect to the surrounding noise.

Discussion

26.	In a balanced mixer, the output _________(a) contains equal amount of all input frequencies(b) does not contain the input frequencies(c) contains the input frequencies(d) is a non-linear mixture of input signalsThe question was posed to me during an interview.The origin of the question is Noise in Pulse Modulated System topic in section Phase Locked Loop & Pulse Modulation of Analog Communications
Answer» The correct CHOICE is (b) does not contain the input FREQUENCIES Best explanation: MIXER is a device that multiples TWO signals. In a balanced mixer, the OUTPUT does not contain the input frequencies. And if it contains the frequency then mixer becomes imbalanced.

Discussion

27.	VFO stands for ________(a) Voltage Feedback Oscillator(b) Variable Feedback Oscillator(c) Voltage Frequency Oscillator(d) Variable Frequency OscillatorThis question was posed to me during an interview.This key question is from PWM in division Phase Locked Loop & Pulse Modulation of Analog Communications
Answer» CORRECT answer is (d) VARIABLE Frequency OSCILLATOR Easiest explanation: VFO stands for Variable Frequency Oscillator. VFO is an oscillator whose frequency can be tuned over some RANGE. It is a necessary component in any tunable radio. It is mostly used in superheterodyne receivers.

Discussion

28.	What is the full form of SONET?(a) Synchronous Optical Network(b) Standard Optical Network(c) Secret Optical Network(d) Service Optical NetworkThe question was posed to me in homework.This intriguing question originated from PWM in section Phase Locked Loop & Pulse Modulation of Analog Communications
Answer» Right answer is (a) Synchronous Optical Network The best explanation: SONET STANDS for Synchronous Optical Network. SONET transfers multiple DIGITAL bit streams in a SYNCHRONIZED WAY over optical fiber USING lasers.

Discussion

29.	The conditions for sinusoidal oscillation from an amplifier are called _________(a) Loop-gain criteria(b) Hartley criteria(c) Biasing criteria(d) Barkhausen criteriaThis question was posed to me by my school principal while I was bunking the class.This question is from PWM in portion Phase Locked Loop & Pulse Modulation of Analog Communications
Answer» Correct choice is (d) Barkhausen criteria The best explanation: The conditions for sinusoidal oscillation from an amplifier are CALLED Barkhausen criteria. It was invented in 1921.

Discussion

30.	Power above the minimum required by an optical receiver is called ________(a) phase margin(b) system margin(c) excess gain(d) gain marginI got this question in a national level competition.Query is from PWM topic in portion Phase Locked Loop & Pulse Modulation of Analog Communications
Answer» RIGHT choice is (b) system margin Easiest explanation: System margin is the TERM USED when the applied POWER is above the minimum required power by an optical receiver.

Discussion

31.	Which parts of a sinusoidal carrier can be modulated?(a) only amplitude(b) only frequency(c) its amplitude, frequency and direction(d) its amplitude, frequency and phase angleThe question was posed to me during an interview.The question is from PWM topic in division Phase Locked Loop & Pulse Modulation of Analog Communications
Answer» RIGHT CHOICE is (d) its amplitude, FREQUENCY and phase angle Easy explanation: If the carrier wave is SINUSOIDAL, then we can vary its amplitude, frequency, and phase in PROPORTION with the wave which is transmitted.

Discussion

32.	The power density of a flicker noise is _________(a) low at high frequencies(b) greater at low frequencies(c) greater at high frequencies(d) low at low frequenciesThis question was posed to me in an interview for job.This question is from PWM topic in portion Phase Locked Loop & Pulse Modulation of Analog Communications
Answer» The correct option is (b) greater at LOW frequencies Easy explanation: Flicker noise is a FORM of noise that exhibits an inverse frequency POWER density curve. It usually OCCURS at low frequencies. Its power density is greater at low frequencies.

Discussion

33.	What is the full form of DWDM?(a) Dense Wavelength Division Multiplexing(b) Dense Wavelength Division Modulation(c) Directed Wavelength Division Multiplexing(d) Directed Wavelength Division ModulationI got this question in a job interview.I want to ask this question from PWM in portion Phase Locked Loop & Pulse Modulation of Analog Communications
Answer» RIGHT choice is (a) Dense Wavelength Division MULTIPLEXING The BEST explanation: DWDM stands for Dense Wavelength Division Multiplexing. In DWDM, each SIGNAL has its own SEPARATED wavelength.

Discussion

34.	FTTC stands for ________(a) Fiber To The Curb(b) Fiber Telephone Transmission Cable(c) Fiber Transmission Timing Cable(d) Fiber Telephone Timing CableI had been asked this question in exam.The above asked question is from PWM in section Phase Locked Loop & Pulse Modulation of Analog Communications
Answer» Correct choice is (a) Fiber To The CURB To ELABORATE: FTTC stands for Fiber To The Curb. It is a replacement of PLAIN Old TELEPHONE SERVICE (POTS) that we see in our neighborhood.

Discussion

Explore topic-wise InterviewSolutions in .

PCS stands for ________(a) Portable Control Service(b) Personal Communication Systems(c) Personal Control Signal(d) Portable Communication SystemsI got this question in semester exam.The query is from Phase Comparator in chapter Phase Locked Loop & Pulse Modulation of Analog Communications

What is the full form of MIN?(a) Multistage Interconnection Network(b) Mobile Identification Number(c) Maximum In-band Noise(d) Minimum In-band NoiseI got this question in an interview for job.My query is from Phase Comparator in section Phase Locked Loop & Pulse Modulation of Analog Communications

Which term is used for voice channels, in GSM?(a) traffic channels(b) noise channels(c) receiver channels(d) transmitter channelsI had been asked this question during an interview.Question is from Phase Comparator in portion Phase Locked Loop & Pulse Modulation of Analog Communications

Pagers use _________(a) VHF band(b) UHF band(c) Both VHF and UHF bands(d) HF bandI had been asked this question in homework.I would like to ask this question from Phase Comparator topic in chapter Phase Locked Loop & Pulse Modulation of Analog Communications

A Bluetooth “piconet” has ________(a) 1 node(b) 2 nodes(c) 2 to 8 nodes(d) 2 to 16 nodesI got this question during an interview.Origin of the question is Bandwidth Requirement for PAM Transition topic in division Phase Locked Loop & Pulse Modulation of Analog Communications

Who invented the technology CDMA?(a) Qualcomm(b) Bell Labs(c) SAP Labs(d) AT&TThis question was addressed to me in an internship interview.The above asked question is from Bandwidth Requirement for PAM Transition in division Phase Locked Loop & Pulse Modulation of Analog Communications

AMPS was designed for POTS only.(a) True(b) FalseThis question was addressed to me by my school principal while I was bunking the class.My enquiry is from Bandwidth Requirement for PAM Transition topic in section Phase Locked Loop & Pulse Modulation of Analog Communications

Fiber-optic cable can be used to connect a transmitter to an antenna.(a) True(b) FalseThis question was posed to me during an internship interview.My question is taken from Noise in Pulse Modulated System topic in section Phase Locked Loop & Pulse Modulation of Analog Communications

The loss in single-mode fiber optic cable due to the glass is about ________(a) 40 dB per km(b) 0.4 dB per km(c) zero(d) 100 dB per kmThe question was posed to me in quiz.Enquiry is from Noise in Pulse Modulated System in portion Phase Locked Loop & Pulse Modulation of Analog Communications

Scattering causes _________(a) refraction(b) loss(c) dispersion(d) reflectionThis question was addressed to me in exam.Asked question is from Noise in Pulse Modulated System in division Phase Locked Loop & Pulse Modulation of Analog Communications

What is used in Hartley oscillator?(a) a piezoelectric crystal(b) two resistor divider(c) a two-capacitor divider(d) a tapped inductorThis question was addressed to me in semester exam.I need to ask this question from PWM in chapter Phase Locked Loop & Pulse Modulation of Analog Communications

Power above the minimum required by an optical receiver is called ________(a) phase margin(b) system margin(c) excess gain(d) gain marginI got this question in a national level competition.Query is from PWM topic in portion Phase Locked Loop & Pulse Modulation of Analog Communications

FTTC stands for ________(a) Fiber To The Curb(b) Fiber Telephone Transmission Cable(c) Fiber Transmission Timing Cable(d) Fiber Telephone Timing CableI had been asked this question in exam.The above asked question is from PWM in section Phase Locked Loop & Pulse Modulation of Analog Communications