MCQ in Modulation Part 8 | ECE Board Exam

(Last Updated On: April 17, 2020)

MCQ in Modulation Part 8 | ECE Board Exam

This is the Multiples Choice Questions Part 8 of the Series in Modulation as one of the Communications Engineering topic. In Preparation for the ECE Board Exam make sure to expose yourself and familiarize in each and every questions compiled here taken from various sources including but not limited to past Board Examination Questions in Electronic System and Technologies, Communications Books, Journals and other Communications References.

MCQ Topic Outline included in ECE Board Exam Syllabi

  • MCQ in Amplitude Modulation
  • MCQ in Phase Modulation
  • MCQ in Sound Pressure Level
  • MCQ in Frequency Modulation
  • MCQ in Pulse Modulation

Continue Practice Exam Test Questions Part 8 of the Series

351. Determine the resonant frequency of a series combination of a 0.001 microfarad capacitor and a 2 – milihenry inductor.

a. 112.5 kHz

b. 35.59 kHz

c. 1125.4 MHz

d. 3.26 MHz

View Answer:

Answer: Option A

Solution:

352. Which of the following is not a typical part of every radio transmitter?

a. Carrier oscillator

b. Driver amplifier

c. Mixer

d. Final power amplifier

View Answer:

Answer: Option C

Solution:

353. What is the approximate magnitude of the impedance of a parallel RLC circuit at resonance?

a. Approximately equal to the circuit resistance

b. Approximately equal to XL

c. Low, as compared to the circuit resistance

d. Approximately equal to XC

View Answer:

Answer: Option A

Solution:

354. What are the three major oscillator circuits often used in radio equipment?

a. Taft, Pierce, and negative feedback

b. Colpitts, Hartley, and Taft

c. Taft, Hartley, and Pierce

d. Colpitts, Hartley, and Pierce

View Answer:

Answer: Option D

Solution:

355. How is a positive feedback coupled to the input in a Hartley oscillator?

a. Through a neutralizing capacitor

b. Through a capacitive divider

c. Through a link coupling

d. Through a tapped coil

View Answer:

Answer: Option D

Solution:

356. How is the positive feedback coupled to the input in a Colpitts oscillator?

a. Through a tapped coil

b. Trough link coupling

c. Through a capacitive divider

d. Through a neutralizing capacitor

View Answer:

Answer: Option C

Solution:

357. How is a positive feedback coupled to the input in a Pierce oscillator?

a. Through a tapped coil

b. Trough link coupling

c. Through a capacitive divider

d. Through a neutralizing capacitor

View Answer:

Answer: Option D

Solution:

358. Which of the three major oscillator circuits used in radio equipment utilizes a quartz crystal?

a. Negative feedback

b. Hartley

c. Colpitts

d. Pierce

View Answer:

Answer: Option C

Solution:

359. What is the piezoelectric effect?

a. Mechanical vibration of a crystal by the application of a voltage

b. Mechanical deformation of a crystal by the application of a magnetic field

c. The generation of electrical energy by the application of light

d. Reversed conduction states when pn-junction is exposed to light

View Answer:

Answer: Option A

Solution:

360. What is the major advantage of a Pierce oscillator?

a. It is easy to neutralize

b. It doesn’t require an LC tank circuit

c. It can be tuned over a wide range

d. It has high output power

View Answer:

Answer: Option B

Solution:

361. Which type of oscillator circuit is commonly used in a VFO?

a. Pierce

b. Colpitts

c. Hartley

d. Negative feedback

View Answer:

Answer: Option B

Solution:

362. Why is the Colpitts oscillator circuit commonly used in a VFO?

a. The frequency is a linear function of the load impedance

b. It can be used with or without crystal lock-in

c. It is stable

d. It has high output power

View Answer:

Answer: Option C

Solution:

363. How is the efficiency of a power amplifier determined?

a. Efficiency = (RF power out / dc power in) x 100%

b. Efficiency = (RF power in / RF power out) x 100%

c. Efficiency = (RF power in / dc power in) x 100%

d. Efficiency = (dc power in / RF power in) x 100%

View Answer:

Answer: Option A

Solution:

364. For reasonably efficient operation of a transistor amplifier, what should be the load resistance be with 12 volts at the collector and a 5 watts power output?

a. 100.3 ohms

b. 14.4 ohms

c. 10.3 ohms

d. 144 ohms

View Answer:

Answer: Option B

Solution:

365. What order of Q is required by a tank circuit sufficient to reduce harmonics to an acceptable level?

a. Approximately 120

b. Approximately 12

c. Approximately 1200

d. Approximately 1.2

View Answer:

Answer: Option B

Solution:

366. What is the flywheel effect?

a. The continued motion of a radio wave through space when the transmitter is turned off

b. The back and forth oscillation of electrons in an LC circuit

c. The use of a capacitor in a power supply to filter rectified AC

d. The transmission of a radio signal to a distant station by several hops through the ionosphere

View Answer:

Answer: Option B

Solution:

367. How can parasitic oscillations be eliminated from a power amplifier?

a. By tuning for maximum SWR

b. By tuning for maximum power output

c. By neutralization

d. By tuning the output

View Answer:

Answer: Option C

Solution:

368. If the spectrum is shifted in frequency with no other changes, this is known as

a. Frequency multiplication

b. Sideband movement

c. Baseband orientation

d. Frequency translation

View Answer:

Answer: Option D

Solution:

369. A device which is capable of causing frequency translation

a. High-Q tank circuit

b. Balanced modulator

c. Low-Q tank circuit

d. IF strip

View Answer:

Answer: Option B

Solution:

370. If the frequency of each component in a signal spectrum is increased by the same fixed amount, this is known as

a. Up conversion

b. Demodulation

c. Frequency translation

d. Both a and c

View Answer:

Answer: Option D

Solution:

371. A particular amplifier is designed to be a frequency doubler. If the input signal frequency is 15.4 MHz, a circuit in the output will be tuned to

a. 7.7 MHz

b. 15.4 MHz

c. 30.8 MHz

d. 61.6 MHz

View Answer:

Answer: Option C

Solution:

372. Any device to be used as a frequency multiplier must be

a. Active

b. Passive

c. Linear

d. Nonlinear

View Answer:

Answer: Option D

Solution:

373. A particular amplifier circuit used for frequency coupling is known as

a. Push-push

b. Push-pull

c. Pull-push

d. Pull-pull

View Answer:

Answer: Option A

Solution:

374. Frequency division is useful in the implementation of a

a. AM demodulation

b. Frequency synthesizer

c. FM demodulator

d. AGC circuit

View Answer:

Answer: Option B

Solution:

375. Indirect frequency synthesizers will include

a. phase-locked loop

b. voltage-controlled oscillators

c. multiple bank crystals

d. both A and B

View Answer:

Answer: Option D

Solution:

376. A particular frequency synthesizer contains only a single crystal. What words describe this synthesizer?

a. Crystal modulated

b. Inexact

c. Indirect

d. Deficient

View Answer:

Answer: Option C

Solution:

377. A recognizable feature of a CW transmitter is

a. Keyed transmitter

b. Power amplification

c. Frequency generation

d. All of the above

View Answer:

Answer: Option D

Solution:

378. The term “pulling” refers to

a. The change of the crystal oscillator frequency by loading

b. One-half cycle operation of a push-pull amplifier

c. Loading on the transmitter caused by the antenna connection

d. Reduction of the power supply terminal voltage as the transmitter is keyed

View Answer:

Answer: Option A

Solution:

379. An AM broadcast transmitter in the multi-kilowatt operating range will have what form of final amplifier?

a. Solid-state devices

b. Vacuum tubes

c. Travelling wave tubes

d. Both a and b

View Answer:

Answer: Option D

Solution:

380. In a broadcast station, the AGC is referred to as

a. Automatic gain control limiter

b. Compression amplifier

c. Loudness controller

d. All of the above

View Answer:

Answer: Option D

Solution:

381. Class C amplifiers are not used in which type of transmitter?

a. AM

b. SSB

c. CW

d. FM

View Answer:

Answer: Option B

Solution:

382. A circuit that isolates the carrier oscillator from load changes is called a

a. Final amplifier

b. Driver amplifier

c. Linear amplifier

d. Buffer amplifier

View Answer:

Answer: Option D

Solution:

383. Bias for class c amplifier produced by an input RC network is known as

a. Signal bias

b. Self-bias

c. Fixed external bias

d. Threshold bias

View Answer:

Answer: Option A

Solution:

384. Collector current in a class C amplifier is

a. Sine wave

b. Half-sine wave

c. Pulse

d. Square wave

View Answer:

Answer: Option C

Solution:

385. Neutralizing is the process of

a. Cancelling the effect of internal device capacitance

b. Bypassing undesired alternating current

c. Reducing gain

d. Eliminating harmonics

View Answer:

Answer: Option A

Solution:

386. In an AM transmitter, a clipper circuit eliminates

a. Harmonics

b. Splatter

c. Over-deviation

d. Excessive gain

View Answer:

Answer: Option B

Solution:

387. The final power amplifier in an FM transmitter usually operates class

a. A

b. B

c. C

d. D

View Answer:

Answer: Option C

Solution:

388. A transistor RF power amplifier can be tuned for

a. Minimum IC in the next stage

b. Zero signal in the next stage

c. Minimum IC in the same stage

d. Maximum IC in the same stage

View Answer:

Answer: Option C

Solution:

389. The purpose of a balanced modulator circuit is to eliminate the

a. Carrier

b. Upper sideband

c. Lower sideband

d. Baseband signal

View Answer:

Answer: Option A

Solution:

390. A frequency multiplier circuit

a. Operates class A

b. Is tuned to a harmonic of the input signal

c. Needs parasitic oscillations

d. Is usually pulse modulated

View Answer:

Answer: Option A

Solution:

391. An IF transformer of a radio receiver operates at 456 kHz. The primary circuit has a Q of 50 and the secondary has a Q of 40. Find the bandwidth using the optimum coupling factor.

a. 10.192 kHz

b. 15.288 kHz

c. 152.88 kHz

d. 101.92 kHz

View Answer:

Answer: Option B

Solution:

392. A varactor has a maximum capacitance of 80pF and is used in a tuned circuit with a 100 microhenry inductor. Find the tuning voltage necessary for the circuit to resonate at twice its resonant frequency with no tuning voltage applied.

a. 5 V

b. 2.5 V

c. 7.5 V

d. 4.25 V

View Answer:

Answer: Option C

Solution:

393. A phase-locked loop has a VCO with a free-running frequency of 14 MHz. As the frequency of the reference input is gradually raised from zero, the loop locks at 12 MHz and comes out of lock again at 18 MHz. Calculate the capture range.

a. 4 MHz

b. 2 MHz

c. 12 MHz

d. 8 MHz

View Answer:

Answer: Option A

Solution:

394. If the frequency fed to the pre-amplifier of a basic transmitter with multipliers is composed of a pair of triplers and a doubler is 198 MHz, what frequency should the oscillator operate?

a. 11 MHz

b. 33 MHz

c. 22 MHz

d. 66 MHz

View Answer:

Answer: Option A

Solution:

395. A phase-locked loop has a VCO with a free running frequency of 14 MHz. As the frequency of the reference input is gradually raised from zero, the loop locks at 12 MHZ and comes out of lock again at 18 MHz. Calculate the lock range.

a. 4 MHz

b. 2 MHz

c. 12 MHz

d. 8 MHz

View Answer:

Answer: Option D

Solution:

396. A crystal oscillator is accurate within 0.0005%. How far off frequency could its output be at 37 MHz?

a. 135 Hz

b. 150 Hz

c. 185 Hz

d. 224 Hz

View Answer:

Answer: Option C

Solution:

397. A transmitter has a carrier power output of 10 W at an efficiency of 80%. How much power must be supplied by the modulating amplifier for 100% modulation?

a. 6.25 W

b. 7.14 W

c. 12.5 W

d. 14.3 W

View Answer:

Answer: Option A

Solution:

398. A transmitter operates from a 16 V supply, with a collector current of 2 A. The modulation transformer has a turns ratio of 4:1. What is the load impedance seen by the audio amplifier?

a. 96 ohms

b. 128 ohms

c. 6 ohms

d. 8 ohms

View Answer:

Answer: Option B

Solution:

399. A collector-modulated class C amplifier has a carrier output power of 150 W and an efficiency of 80%. Calculate the transistor power dissipation with 100% modulation.

a. 93.75 W

b. 120 W

c. 64 W

d. 56.25 W

View Answer:

Answer: Option D

Solution:

400. An AM transmitter is required to produce 20 W of carrier power when operating from a 25 V supply. What is the required load impedance as seen from the collector?

a. 15.625 ohms

b. 22.5 ohms

c. 11.25 ohms

d. 31.25 ohms

View Answer:

Answer: Option A

Solution:

Questions and Answers in Modulation Series

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

MCQ in Modulation
PART 1: MCQ from Number 1 – 50                        Answer key: PART 1
PART 2: MCQ from Number 51 – 100                   Answer key: PART 2
PART 3: MCQ from Number 101 – 150                 Answer key: PART 3
PART 4: MCQ from Number 151 – 200                 Answer key: PART 4
PART 5: MCQ from Number 201 – 250                 Answer key: PART 5
PART 6: MCQ from Number 251 – 300                 Answer key: PART 6
PART 7: MCQ from Number 301 – 350                 Answer key: PART 7
PART 8: MCQ from Number 351 – 400                 Answer key: PART 8
PART 9: MCQ from Number 401 – 450                 Answer key: PART 9
PART 10: MCQ from Number 451 – 500                 Answer key: PART 10

Complete List of MCQ in Communications Engineering per topic

DOWNLOAD PDF / PRINT
Print Friendly, PDF & Email
Please do Subscribe on YouTube!

P inoyBIX educates thousands of reviewers and students a day in preparation for their board examinations. Also provides professionals with materials for their lectures and practice exams. Help me go forward with the same spirit.

“Will you subscribe today via YOUTUBE?”

Subscribe

Add Comment

PinoyBIX Engineering. © 2014-2020 All Rights Reserved | How to Donate? | Follow me on Blogarama DMCA.com Protection Status

Math Solution

Advanced Math problem age work mixture digit motion Analytic Geometry 01 problem Analytic Geometry 02 problem clock variation progression misc Combination problem Differential Calculus 01 Problem Differential Calculus 02 Problem Differential Equations Problem Fundamentals in Algebra Fundamentals in Algebra Problem Integral Calculus problem Permutation problem Plane Geometry problem Plane Trigonometry problem Probability problem quadratic equation binomial theorem logarithms Solid Geometry problem Spherical Trigonometry problem System of Numbers Problem Venn Diagram Problem

Questions and Answers in Mathematics

Advanced Math Age Work Mixture Digit Motion Algebra and General Mathematics Analytic Geometry 01 Analytic Geometry 02 Calculus Clock Variation Progression Misc Differential Calculus 01 Differential Calculus 02 Differential Equations Engineering Mathematics Geometry Integral Calculus Plane Geometry Plane Trigonometry Probability and Statistics Quadratic Equation Binomial Theorem Logarithms Solid Geometry Spherical Trigonometry System of Numbers Trigonometry

video

Pre-board in Electronics Engineering

Answers Pre-board in Electronics Engineering - Answers

Questions and Answers

Basic Television - Grob TV Boylestad Questions and Answers Computer Principles Electrical Circuit Electricity and Magnetism Fundamentals Electronic Circuits Floyd Questions and Answers Floyd Self-test Gibilisco Questions and Answers Grob Questions and Answers Industrial Electronics Principles and Applications Malvino Questions and Answers Microelectronics Power Generators / Sources / Principles and Applications Solid State Devices Tests and Measurements Vacuum Tubes

Pre-board in Communications Engineering

Answers

Questions and Answers

Acoustics Antennas Blake Questions and Answers Broadcasting and Cable TV System Digital Communication Networks Forouzan Frenzel Self-test Kennedy Questions and Answers Microwave Communications Miscellaneous Questions in Communications Modulation Navigational Aids and Radar Systems Noise Optical Fiber Communications Radiation and Wave Propagation Satellite Communications Transmission Fundamentals Wire and Wireless Communications

GEAS Solution

Dynamics problem Economics problem Physics problem Statics problem Strength problem Thermodynamics problem

Pre-board in GEAS

Questions and Answers in GEAS

Engineering Economics Engineering Laws and Ethics Engineering Management Engineering Materials Engineering Mechanics General Chemistry Giancoli Physics Physics Strength of Materials Thermodynamics
Online Tool: Electrical Charge Conversions
Online Tool: Electrical Charge Conversions
Online Tool: Color Code Conversions
Online Tool: Color Code Conversions
Online Tool: Weight Measurement Conversions
Online Tool: Weight Measurement Conversions
Online Tool: Temperature Measurement Conversions
Online Tool: Temperature Measurement Conversions