Miscellaneous MCQs in Communications Engineering Part VIII - Answers

Answers key for the Compiled Miscellaneous Multiple Choice Questions in Communications Engineering Part 8 of the series.

Answers in Miscellaneous MCQs in Communications Engineering Part VIII

Below are the answers key for the Miscellaneous Multiple Choice Questions in Communications Engineering Part 8.

351. ______ are transmission circuits interconnecting two different switching centers.

  • a. Toll center
  • b. Trunk circuits
  • c. Hybrid circuits
  • d. Intertoll circuits

352. The phone system begins with ______, which is the pair of wires that connects the central office to the user’s phone.

  • a. Loop extenders
  • b. Local change
  • c. Switching office
  • d. Local loop

353. When you dial the digit “8”, the corresponding low and high group tones are generated by the phone and sent to the central office are______.

  • a. 852 and 1336 Hz
  • b. 770 and 679 Hz
  • c. 941 and 1477 Hz
  • d. 770 and 1209 Hz

354. A signal travels via cables (propagation velocity 0.7 c) from New York to Los Angeles, a distance of 3000 miles. What are the talker echo and listener echo times?

  • a. 46 ms and 78 ms
  • b. 38 ms and 69 ms
  • c. 46 ms and 69 ms
  • d. 38 ms and 78 ms

355. The word telephone is derived from the Greek word tele, meaning _____, and phone, meaning ________.

  • a. Type, audio
  • b. Far, sound
  • c. Scope, sound
  • d. Far, handset

356. What are the second harmonics of the tones for the digit “3”?

  • a. 1540, 2954 Hz
  • b. 1394, 2954 Hz
  • c. 770, 1209 Hz
  • d. 1714, 1852 Hz

357. A European unit of the traffic intensity equal to 1/30 of an Erlang.

  • a. Call second
  • b. EBHC
  • c. Erlang
  • d. Call minute

358. A two state switching device containing one or more elements that have a low transmission impedance in one state and a very high one in the others.

  • a. Crosspoint
  • b. Coordinate switch
  • c. Folded Network
  • d. Expansions

359. Is the representation of a speech signal or other analog signal by sampling at a regular rate and converting each sample to binary numbers.

  • a. QAM
  • b. FSK
  • c. PCM
  • d. PAM

360. A murray loop is connected to locate a ground in cable between two cities 64 km apart. The lines forming the loop are identical. With the bridge balanced, R1 = 645 ohms and R2 = 476 ohms. How far is the grounded point (p) from the test end.

  • a. 35.45 km
  • b. 26.28 km
  • c. 72.06 km
  • d. 54.35 km

361. Refers to the specific of how these various waves travel under different circumstances.

  • a. Scatter
  • b. Propagation
  • c. Waveguide propagation
  • d. radiation

362. Travel in a straight line from the transmitting antenna to the receiving antenna.

  • a. Ground wave
  • b. Scatter
  • c. Space wave
  • d. Sky wave

363. Are intended to pass through the earth’s ionosphere and into space, or travel from a spaced-based transmitter to a receiver on the ground.

  • a. Satellite waves
  • b. Ground waves
  • c. Line of sight
  • d. None of these

364. Ducting is also called____.

  • a. Super ducting
  • b. Superrefraction
  • c. Superdiffraction
  • d. refraction

365. Frequencies in the UHF range propagate by means of

  • a. Ground wave
  • b. Surface wave
  • c. Sky wave
  • d. Space wave

366. An electromagnetic wave travel in free space, only one of the following can happen to them.

  • a. Absorption
  • b. Attenuation
  • c. Refraction
  • d. reflection

367. VLF waves are for some types of services because

  • a. Of low powers required
  • b. They are very reliable
  • c. The transmitting antennas are of convenient size
  • d. They penetrate the ionosphere easily

368. A region where the air pressure is so low that the free electron and ions can move about for some time without getting close enough to recombine into neutral atoms.

  • a. Ionosphere
  • b. Troposphere
  • c. Sky
  • d. Sky wave propagation

369. ________ is the distance between two wave fronts having the same phase at any given instant.

  • a. Wavefront
  • b. Wavelength
  • c. Wave distance
  • d. Field intensity

370. Modulation is used to ________.

  • a. Increase the carrier power
  • b. Reduce bandwidth used
  • c. Allow the use of practical antennas
  • d. Shorten the transmission channel

371. A pre-emphasis circuit improves the signal-to-noise of an FM signal by __________.

  • a. Amplifying the higher audio frequency
  • b. Boosting the bass frequency
  • c. Amplifying the whole frequency
  • d. Increase the carrier power

372. In an AM broadcast super heterodyne receiver, the

  • a. Local oscillator operates below the signal frequency
  • b. Mixer input must be tuned to the signal frequency
  • c. Local oscillator frequency normally double the IF
  • d. RF amplifiers normally works at 455 kHz above the carrier frequency

373. Carriers are spaced at 20 kHz, beginning at 100 kHz. Each carrier is modulated by a signal with 5 kHz bandwidth. Is there interference from sideband overlap?

  • a. No
  • b. Yes
  • c. Maybe
  • d. Sure

374. The modulated peak value of a signal is 10 V and the unmodulated carrier value is 8V. What is the modulated index?

  • a. 0.80
  • b. 0.25
  • c. 0.50
  • d. 0.75

375. What is the maximum suppression for a phase error of 2o?

  • a. 41.2 dB
  • b. 35.2 dB
  • c. 23.6 dB
  • d. 12.7 dB

376. An information signal that is sent directly without modulating any carrier is called _________.

  • a. Modulating frequency
  • b. Baseband AM
  • c. Carrier frequency
  • d. Broadband AM

377. Superheterodyne receiver was invented by

  • a. A.H. Armstrong
  • b. H.E. Armstrong
  • c. E.H. Armstrong
  • d. H.A. Armstrong

378. Convert the RF signal to the intermediate frequency,

  • a. Mixer
  • b. Local oscillator
  • c. Mixer and local oscillator
  • d. Mixer and IF stage

379. ______ is a very important part of the receiving system.

  • a. RF amplifier
  • b. Mixer
  • c. Detector
  • d. AGC

380. The frequency used for out of band signaling under CCITT standard.

  • a. 3825 Hz
  • b. 3700 Hz
  • c. Both a and b
  • d. Either a and b

381. The following are advantages of the optical fiber except _____.

  • a. Greater capacity
  • b. Crosstalk immunity
  • c. Safer to handle
  • d. Lower initial cost of installation

382. The frequencies used for fiber optic system

  • a. 1014 to 1015 Hz
  • b. 107 to 1010 Hz
  • c. 109 to 1012 Hz
  • d. 1011 to 1011 Hz

383. Plastic fibers have the following advantage over glass fiber:

  • a. Flexibility
  • b. Ruggedness
  • c. Ease of installation
  • d. Low attenuation

384. A site that contains the cellular radio equipment. It can have one or more _____.

  • a. Base
  • b. Central Business District
  • c. boundary
  • d. Coverage

385. A modulated method using frequency changes to transmit data. Usually only two frequencies are used.

  • a. FM
  • b. GSM
  • c. FSK
  • d. FCC

386. Is contained in the NAM (Number Assignment Module)

  • a. ERP
  • b. FDMA
  • c. DTMF
  • d. ESN

387. The amount of attenuation present in a waveguide is due to _________.

  • a. The air dielectric filling the guide
  • b. The fine coating of silver inside
  • c. Losses the conducting walls of the guide
  • d. I2R loss

388. The advantage of microwave baseband repeater over heterodyne repeater is:

  • a. It improve noise performance
  • b. It increase power output
  • c. It provide drops and inserts
  • d. All of these

389. The correctness and accuracy of the transmitted message content is:

  • a. Verified by the modem
  • b. Determined by the sender and receiver, not by the communications system.
  • c. Ensured by use of digital techniques
  • d. All of these

390. Transmission of binary signals requires ________.

  • a. Less bandwidth than analog
  • b. More bandwidth than analog
  • c. The same bandwidth as analog
  • d. A license from the FAA

391. Which of the following is a characteristic of a LAN?

  • a. Parallel transmission
  • b. Unlimited expansion
  • c. Low cost access for low bandwidth channels
  • d. Application independent interfaces

392. ADF means

  • a. Audio Direction Findings
  • b. Automatic Direction Finder
  • c. Automatic Detection Finder
  • d. Alternate Detection Form

393. A navigational system which employs gyroscopes, accelerometers and associated electronics to sense burning rates and accelerations associated with the rotation of the earth.

  • a. CNS
  • b. INS
  • c. GPS
  • d. VOR

394. It is referred to as the range and azimuth display.

  • a. A-scan
  • b. B-Scan
  • c. C-Scan
  • d. PPI

395. GCA operates with:

  • a. DME
  • b. Master and slave stations
  • c. Ground-based radar
  • d. Local radio stations

396. Bass response means:

  • a. Maximum high frequency response
  • b. Emphasizing the high audio frequencies
  • c. By passing high audio frequencies
  • d. By passing low audio frequencies

397. Sound intensity varies directly to the square of:

  • a. Density
  • b. Velocity
  • c. Pressure
  • d. frequency

398. Audience per person usually have an absorption coefficient in unit pert sq. ft. of :

  • a. 3.5
  • b. 4.7
  • c. 6.7
  • d. 7.4

399. Early reflected sound is also called as:

  • a. Echo
  • b. Reverberation
  • c. Pure sound
  • d. Intelligible sound

100. The optimum reverberation time for a 6000 cu. Ft. room is about:

  • a. 2.0 sec
  • b. 1.5 sec
  • c. 1.1 sec
  • d. 1.0 sec

The Series

Following is the list of multiple choice questions in this brand new series:

Miscellaneous Communications Engineering MCQs
PART 1: MCQs from Number 1 – 50                        Answer key: PART I
PART 2: MCQs from Number 51 – 100                   Answer key: PART II
PART 3: MCQs from Number 101 – 150                 Answer key: PART III
PART 4: MCQs from Number 151 – 200                 Answer key: PART IV
PART 5: MCQs from Number 201 – 250                 Answer key: PART V
PART 6: MCQs from Number 251 – 300                 Answer key: PART VI
PART 7: MCQs from Number 301 – 350                 Answer key: PART VII
PART 8: MCQs from Number 351 – 400                 Answer key: PART VIII
PART 9: MCQs from Number 401 – 450                 Answer key: PART IX
PART 10: MCQs from Number 451 – 500                 Answer key: PART X

Complete List of MCQs in Communications Engineering per topic


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