MCQ in Noise Part 1 | ECE Board Exam

(Last Updated On: April 13, 2021)

MCQ in Noise Part 1 | ECE Board Exam

This is the Multiples Choice Questions Part 1 of the Series in Noise 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 External Noise
  • MCQ in Phase Noise
  • MCQ in Noise Calculation and Measurements
  • MCQ in Radio Interference

Start Practice Exam Test Questions Part 1 of the Series

1. What is the non-continuous noise of irregular pulses or spikes of duration with high amplitudes?

A. Wander

B. Jitter

C. Hits

D. Singing

View Answer:

Answer: Option B

Solution:

2. What theorem sets a limit on the maximum capacity of a channel with a given noise level?

A. Nyquist theorem

B. Hartley law

C. Shannon-Hartley theorem

D. Shannon theorem

View Answer:

Answer: Option C

Solution:

3. Quantizing noise occurs in

A. PCM

B. PLM

C. PDM

D. PAM

View Answer:

Answer: Option A

Solution:

4. Noise always affects the signal in a communications systems at the ________.

A. transmitter

B. channel

C. information source

D. destination

View Answer:

Answer: Option B

Solution:

5. _________ is the random and unpredictable electric signals from natural causes, both internal and external to the system.

A. Interference

B. Attenuation

C. Distortion

D. Noise

View Answer:

Answer: Option D

Solution:

6. Noise from random acoustic or electric noise that has equal energy per cycle over a specified total frequency band.

A. Gaussian noise

B. Whiter noise

C. Thermal noise

D. All of the above

View Answer:

Answer: Option D

Solution:

7. Which causes a quantization noise in PCM system?

A. Serial transmission errors

B. The approximation of the quantized signal

C. The synchronization between encoder and decoder

D. Binary coding techniques

View Answer:

Answer: Option B

Solution:

8. A particular circuit that rids FM of noise

A. Detector

B. Discriminator

C. Phase Shifter

D. Limiter

View Answer:

Answer: Option D

Solution:

9. What is the reference noise temperature in degrees Celsius?

A. 17

B. 273

C. 25

D. 30

View Answer:

Answer: Option A

Solution:

10. Unwanted radio signal on assigned frequency.

A. Splatter

B. RFI

C. Noise

D. EMI

View Answer:

Answer: Option C

Solution:

11. What is the reliable measurement for comparing amplifier noise characteristics?

A. Thermal agitation noise

B. Noise factor

C. Noise margin

D. Signal-to-noise

View Answer:

Answer: Option B

Solution:

12. _________ is measured on a circuit when it is correctly terminated but does not have any traffic.

A. White noise

B. Galactic noise

C. Impulse noise

D. Atmospheric noise

View Answer:

Answer: Option A

Solution:

13. Which standard recommends crosstalk limits?

A. CCIT G.152

B. CCIT G.150

C. CCIT G.151

D. CCIT G.161

View Answer:

Answer: Option C

Solution:

14. Which standard is utilized in intermodulation noise rates on PCM audio channels?

A. CCIT Rec. G.151

B. CCIT Rec. G.172

C. CCIT Rec. G.190

D. CCIT Rec. G.190

View Answer:

Answer: Option B

Solution:

15. What is the reference frequency of CCIT phosphomeric noise measurement?

A. 800 Hz

B. 1000 Hz

C. 1500 Hz

D. 3400 Hz

View Answer:

Answer: Option A

Solution:

16. Reference temperature use in noise analysis

A. 75K

B. 250K

C. 290K

D. 300K

View Answer:

Answer: Option C

Solution:

17. Which noise is produced by lighting discharges in thunderstorms?

A. White noise

B. Extraterrestrial noise

C. Industrial noise

D. Atmospheric noise

View Answer:

Answer: Option D

Solution:

18. Man-made noise is usually from _______.

A. transmission over power lines and by ground wave

B. sky-wave

C. space-wave

D. troposphere

View Answer:

Answer: Option A

Solution:

19. nif stands for

A. Non-intrinsic figure

B. Noise improvement factor

C. Narrow intermediate frequency

D. Noise interference figure

View Answer:

Answer: Option B

Solution:

20. Industrial noise frequency is between _____.

A. 0 to 10 KHz

B. 160 MHz to 200 MHz

C. 15 to 160 MHz

D. 200 to 3000 MHz

View Answer:

Answer: Option C

Solution:

21. External noise fields are measured in terms of _______.

A. rms values

B. dc values

C. average values

D. peak values

View Answer:

Answer: Option D

Solution:

22. Form of interference caused by rain or dust storms.

A. Precipitation static

B. Shot-noise

C. Galactic noise

D. Impulse noise

View Answer:

Answer: Option A

Solution:

23. At 17˚C, the noise voltage generated by 5 kΩ resistor, operating over a bandwidth of 20 KHz is

A. 1.3 nV

B. 1.3 µV

C. 1.3 pV

D. 1.3 mV

View Answer:

Answer: Option B

Solution:

24. ________ is an electric noise produced by thermal agitation of electrons in conductor and semiconductor.

A. External noise

B. Internal noise

C. Thermal noise

D. Flicker

View Answer:

Answer: Option C

Solution:

25. Three identical circuits having 10 dB signal noise-to-noise ratio each are connected in tandem with each other, what is the overall S/N?

A. 5.23 dB

B. 14.77 dB

C. 30 dB

D. 40 dB

View Answer:

Answer: Option A

Solution:

26. The noise figure of the first circuit in tandem connection is 10.5 dB while its power gain is 15, what is the over all noise figure if the second circuit has a noise figure of 11 dB?

A. 11.59 dB

B. 11.23 dB

C. 10.79 dB

D. 10.5 dB

View Answer:

Answer: Option C

Solution:

27. Is the interference coming from other communications channels?

A. Jitter

B. Crosstalk

C. RFI

D. EMI

View Answer:

Answer: Option B

Solution:

28. What is the reference noise level?

A. 10 pW

B. 0 dBm

C. 1mW

D. -90 dBm

View Answer:

Answer: Option D

Solution:

29. What is the unit of noise power of psophometer?

A. pWp

B. dBa

C. dBm

D. dBrn

View Answer:

Answer: Option A

Solution:

30. A large emission of hydrogen from the sun that affects communications.

A. Solar flare

B. Cosmic disturbance

C. Ballistic disturbance

D. Solar noise

View Answer:

Answer: Option A

Solution:

31. Atmospheric noise is known as _______noise.

A. static

B. cosmic

C. solar

D. lunar

View Answer:

Answer: Option A

Solution:

32. Standard design reference for environmental noise temperature.

A. 300K

B. 290K

C. 32˚F

D. 212˚F

View Answer:

Answer: Option B

Solution:

33. Absolute temperature in Kelvin.

A. ˚C + 273

B. ˚C + 75

C. ˚C + 19

D. ˚C + 290

View Answer:

Answer: Option A

Solution:

34. If bandwidth is doubled, the signal power is _________.

A. not changed

B. quadrupled

C. tripled

D. doubled

View Answer:

Answer: Option A

Solution:

35. Name one or more sources of noise bearing on electronic communications.

A. Steam boiler

B. Galaxies

C. Internal combustion engine

D. Both B and C

View Answer:

Answer: Option D

Solution:

36. The transmitter technique adopted to reduce the noise effect of the preceding question is called

A. noise masking

B. anitnoise

C. noise killing

D. preemphasis

View Answer:

Answer: Option D

Solution:

37. Deemphasis in the receiver in effect attenuates modulating signal components and noise in what frequency range?

A. dc

B. low

C. intermediate

D. high

View Answer:

Answer: Option D

Solution:

38. Atmospheric noise or static is not a great problem

A. at frequencies below 20 MHz

B. at frequencies below 5 MHz

C. at frequencies above 30 MHz

D. at frequencies above 1 MHz

View Answer:

Answer: Option C

Solution:

39. What is the proper procedure for suppressing electrical noise in a mobile station?

A. Apply shielding and filtering where necessary

B. Insulate a all plain sheet metal surfaces from each other

C. Apply anti-static spray liberally to all nonmetallic

D. Install filter capacitors in series with all dc wiring

View Answer:

Answer: Option A

Solution:

40. Where is the noise generated that primarily determines the signal-to-noise ratio in a VHF (150MHz) marine-band receiver?

A. Man-made noise

B. In the atmosphere

C. In the receiver front end

D. In the ionosphere

View Answer:

Answer: Option C

Solution:

41. The difference between signal strength at a given point and a reference level is________.

A. power

B. dBm

C. level

D. ratio

View Answer:

Answer: Option C

Solution:

42. Interfering effect of noise, C message weighted, is _________.

A. dBa

B. dBm

C. dBmc

D. dB

View Answer:

Answer: Option C

Solution:

43. F1A weighting refers to ___________.

A. -90 dBm

B. dBrnc0

C. dBrnc

D. F1A handset

View Answer:

Answer: Option C

Solution:

44. Reading a 58 dBrnC on your Western Electric 3A test set at a +7 test point is equal to ______ dBrnc0.

A. 58

B. 51

C. 65

D. 27

View Answer:

Answer: Option B

Solution:

45. Reading a 58 dBrn, at a +7 test point is equal to ________ dBa0.

A. 26

B. 65

C. 51

D. 46

View Answer:

Answer: Option D

Solution:

46. A reading of -50 dBm on the disturbing pair, and -80 on the disturbed pair equals _____ dB of crosstalk coupling.

A. 20

B. 30

C. 60

D. 25

View Answer:

Answer: Option B

Solution:

47. Power is __________.

A. actual amount of power reference to 1mW

B. logarithmic ratio of two powers

C. definite amount of energy per time period

D. current flow per time period

View Answer:

Answer: Option C

Solution:

48. 15 dBa F1A weighted, equals ___________.

A. -90 dBm

B. -82 dBm

C. -85 dBm

D. -70 dBm

View Answer:

Answer: Option D

Solution:

49. You are measuring noise in a voice channel with a Lenkurt 601A, F1A weighting network and a flat meter. Your meter reads -47dBm. What is this reading in dBa?

A. 77 dBa

B. 35 dBa

C. 38 dBa

D. 32 dBa

View Answer:

Answer: Option C

Solution:

50. You are measuring noise at a +3 dB level point, using the Lenkurt 601A, F1A weighting network, and a flat meter. The meter reading is -57dBm. This is ________dBa0.

A. 20

B. 15

C. 25

D. 17

View Answer:

Answer: Option C

Solution:

Questions and Answers in Noise Series

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

MCQ in Noise
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

Complete List of MCQ in Communications Engineering per topic

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