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MCQ in Modulation Part 13 | ECE Board Exam

(Last Updated On: February 24, 2021)

MCQ in Modulation Part 13 | ECE Board Exam

This is the Multiples Choice Questions Part 13 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 13 of the Series

601. It is the first stage of the receiver and is therefore often called the receiver front end.

a. mixer

b. RF section

c. local oscillator

d. IF stage

View Answer:

Answer: Option B

Solution:

602. One of the following cannot be used to remove the unwanted sideband in SSB. This is the

a. filter system

b. phase-shift method

c. third method

d. balanced modulator

View Answer:

Answer: Option D

Solution:

603. R3E modulation is sometimes used to

a. allow the receiver to have a frequency synthesizer

b. simplify the frequency stability problem in reception

c. reduce the power that must be transmitted

d. reduce the bandwidth required for transmission

View Answer:

Answer: Option B

Solution:

604. To provide two or more voice circuits with the same carrier, it is necessary to use

a. ISB

b. carrier reinsertion

c. SSB with pilot carrier

d. Lincomplex

View Answer:

Answer: Option A

Solution:

605. A type of AGC is similar to conventional AGC except that the receive signal is monitored closer to the front end of the receiver and the correction voltage is fed forward to the IF amplifiers

a. ISB

b. delayed AGC

c. complex AGC

d. simple AGC

View Answer:

Answer: Option B

Solution:

606. Having an information signal change some characteristics of a carrier signal is called

a. multiplexing

b. modulation

c. duplexing

d. linear mixing

View Answer:

Answer: Option B

Solution:

607. A circuit that compensates for minor variations in the received RF signal level

a. automatic volume control

b. automatic frequency control

c. automatic gain control

d. automatic phase control

View Answer:

Answer: Option C

Solution:

608. Which of the following is not true about AM?

a. the carrier amplitude varies

b. the carrier frequency remains constant

c. the carrier frequency changes

d. the information signal amplitude changes the carrier amplitude

View Answer:

Answer: Option C

Solution:

609. A modulator circuit performs what mathematical operation on its two inputs?

a. addition

b. multiplication

c. division

d. square root

View Answer:

Answer: Option B

Solution:

610. If m is greater than 1, what happens?

a. normal operation

b. carrier drops to 0

c. information signal is distorted

d. nothing happens

View Answer:

Answer: Option C

Solution:

611. The outline of the peaks of a carrier has the shape of modulating signal and is called _______.

a. trace

b. wave shape

c. envelope

d. carrier variation

View Answer:

Answer: Option C

Solution:

612. Overmodulation occurs when

a. Vm > Vc

b. Vm < Vcc. Vm = Vcd. Vm = Vc = 0[toggle title="View Answer:"]Answer: Option A

Solution:

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613. The new signal produced by modulation are called __________.

a. spurious emission

b. harmonics

c. intermodulation products

d. sidebands

View Answer:

Answer: Option D

Solution:

614. An AM signal has a carrier power of 5W, the percentage of modulation is 80 percent. The total power sideband is _________.

a. 0.8 W

b. 1.6 W

c. 2.5 W

d. 4.0 W

View Answer:

Answer: Option B

Solution:

615. For 100 percent modulation, what percentage of power is in each sideband

a. 25 percent

b. 33.3 percent

c. 50 percent

` d. 100 percent

View Answer:

Answer: Option B

Solution:

616. An AM transmitter has a percentage of modulation of 88, the carrier power is 440 W. The power in one sideband is

a. 85 W

b. 110 W

c. 170 W

d. 610 W

View Answer:

Answer: Option A

Solution:

617. An AM signal without the carrier is called ______.

a. SSB

b. vestigial sidebands

c. FM signal

d. DSB

View Answer:

Answer: Option D

Solution:

618. It is a form of amplitude modulation in which the carrier is transmitted at full power, but only one of the sidebands is transmitted.

a. SSBFC

b. SSBSC

c. SSBRC

d. ISB

View Answer:

Answer: Option A

Solution:

619. With single-sideband full carrier, 100% modulation would mean a carrier power of how many percent of the total transmitted power?

a. 80%

b. 20%

c. 50%

d. 40%

View Answer:

Answer: Option A

Solution:

620. It is a form of amplitude modulation in which the carrier is suppressed and one of the sidebands removed

a. SSBFC

b. ISB

c. vestigial sideband

d. SSBSC

View Answer:

Answer: Option D

Solution:

621. It is a form of amplitude modulation in which one sideband is totally removed and the carrier voltage is reduced to approximately 10% of its unmodulated amplitude

a. independent sideband

b. SSBFC

c. SSBRC

d. SSBSC

View Answer:

Answer: Option C

Solution:

622. It is a form of amplitude modulation in which a single carrier frequency is independently modulated by two different modulating signal.

a. vestigial sideband

b. DSBFC

c. independent sideband

d. SSBFC

View Answer:

Answer: Option C

Solution:

623. It is a form of amplitude modulation in which the carrier and one complete sideband are transmitted, but only part of the second sideband is transmitted.

a. independent sideband

b. vestigial sideband

c. DSBFC

d. SSBSC

View Answer:

Answer: Option B

Solution:

624. It is the rms power developed at the crest of the modulation envelope of SSBSC.

a. carrier power

b. total transmitted power

c. sideband power

d. peak envelope power

View Answer:

Answer: Option D

Solution:

625. Which of the following is not true about single-sideband transmission?

a. power is conserved

b. selective fading is eliminated

c. bandwidth is conserved

d. tuning is easy

View Answer:

Answer: Option D

Solution:

626.A circuit that produces a double sideband suppressed carrier signal is called ____________.

a. filter

b. mixer

c. demodulator

d. balanced modulator

View Answer:

Answer: Option D

Solution:

627. A balanced modulator is sometimes called _________.

a. balanced ring modulator

b. balanced resistor modulator

c. balanced lattice modulator

d. any of these

View Answer:

Answer: Option C

Solution:

628. A type of filter that receives electrical energy, converts it to mechanical vibrations and then converts the vibrations back to electrical energy at its output.

a. crystal filter

b. mechanical filter

c. LC filter

d. SAW filter

View Answer:

Answer: Option B

Solution:

629. A type of filter that uses acoustic energy rather than electromechanical energy to provide excellent performance for precise bandpass filtering.

a. SAW filter

b. RC filter

c. mechanical filter

d. crystal filter

View Answer:

Answer: Option A

Solution:

630. The difference between the IF and the BFO frequencies is called _________.

a. information signal

b. beat frequency

c. carrier signal

d. heterodyned signal

View Answer:

Answer: Option A

Solution:

631. It is a circuit which is a narrowband PLL that tracks the pilot carrier in the composite SSBRC receiver signal and uses the recovered carrier to regenerate coherent local oscillator frequencies in the synthesizer.

a. beat frequency oscillator

b. mechanical filter

c. local oscillator

d. carrier recovery circuit

View Answer:

Answer: Option D

Solution:

632. A system that provides narrowband voice communications for land mobile services with nearly the quality achieved with FM systems and do it using less than one-third the bandwidth.

a. SSBSC

b. DSBFC

c. ACSSB

d. SSBAC

View Answer:

Answer: Option C

Solution:

633. It is a process of combining transmissions from more than one source and transmitting them over a common facility such as metallic or optical fiber cable or a radio-frequency channel.

a. buffering

b. modulation

c. multiplexing

d. demultiplexing

View Answer:

Answer: Option C

Solution:

634. It is an analog method of combining two or more analog sources that originally occupied the same frequency band in such a manner that the channels do not interfere with each other.

a. ATM

b. FDM

c. TDM

d. WDM

View Answer:

Answer: Option B

Solution:

635. It is a multiplexing method that uses double-sideband suppressed-carrier transmission to combine two information sources into a single composite waveform.

a. QM

b. WDM

c. TDM

d. FDM

View Answer:

Answer: Option A

Solution:

636. Single-sideband transmitters are rated in _________.

a. rms power

b. dc power

c. average power

d. peak envelope power

View Answer:

Answer: Option D

Solution:

637. In an SSB transmitter, one is most likely to find a __________.

a. class C audio amplifier

b. tuned modulator

c. class B RF amplifier

d. class A RF output amplifier

View Answer:

Answer: Option D

Solution:

638. Indicate in which one of the following only one sideband is transmitted:

a. H3E

b. A3E

c. B8E

d. C3F

View Answer:

Answer: Option A

Solution:

639. One of the following cannot be used to remove the unwanted sideband in SSB. This is the

a. filter system

b. phase-shift method

c. third method

d. balanced modulator

View Answer:

Answer: Option D

Solution:

640. R3E modulation is sometimes used to

a. allow the receiver to have a frequency synthesizer

b. simplify the frequency stability problem in reception

c. reduce the power that must be transmitted

d. reduce the bandwidth required for transmission

View Answer:

Answer: Option B

Solution:

641. To provide two or more voice circuits with the same carrier, it is necessary to use

a. ISB

b. carrier reinsertion

c. SSB with pilot carrier

d. Lincomplex

View Answer:

Answer: Option A

Solution:

642. The main advantage of SSB over standard AM or DSB is

a. less spectrum is used

b. simpler equipment is used

c. less power is consumed

d. a higher modulation percentage

View Answer:

Answer: Option A

Solution:

643. In SSB, which sideband is the best to use?

a. upper

b. lower

c. neither

d. depends upon the use

View Answer:

Answer: Option D

Solution:

644. The output of an SSB transmitter with a 3.85 MHz carrier and a 1.5 kHz sine wave modulating tone is

a. a 3.8485 MHz sine wave

b. a 3.85 MHz sine wave

c. 3.85, 3.8485 and 3.8515 MHz sine waves

d. 3848.5 and 3851.5 MHz sine waves

View Answer:

Answer: Option A

Solution:

645. An SSB transmitter produces a 400 V peak to peak signal across a 52 ohm antenna load. The PEP output is

a. 192.2 W

b. 384.5 W

c. 769.2 W

d. 3077 W

View Answer:

Answer: Option B

Solution:

646. The output power of SSB transmitter is usually expressed is terms of

a. average power

b. RMS power

c. peak to peak power

d. peak envelope power

View Answer:

Answer: Option D

Solution:

647. An SSB transmitter has a PEP rating of 1 kilowatts. The average output power is in the range of

a. 150 to 450 W

b. 100 to 300 W

c. 250 to 333 W

d. 3 to 4 kW

View Answer:

Answer: Option C

Solution:

648. In amplitude modulation technique, the unmodulated carrier is referred to as having___..

a. 100% modulation

b. 0% modulation

c. 50% modulation

d. overmodulated

View Answer:

Answer: Option B

Solution:

649. What is the process in radio communication where the information or intelligent signal is at lower frequency is put unto higher radio frequency for transmission to receiving station?

a. detection

b. mixing

c. modulation

d. demodulation

View Answer:

Answer: Option C

Solution:

650. Which of the following signals is suppressed by balanced modulator circuit?

a. 1st IF signal

b. carrier signal

c. harmonics

d. 2nd IF signal

View Answer:

Answer: Option B

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

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