PinoyBIX Engineering Problem Solving and Reference

Below are the answers key for Multiple Choice Questions in Chapter 18: Introduction to Fiber Optic Technology from the book Electronic Communication Systems by George Kennedy. Make sure to familiarize each and every questions to increase the chance of passing the ECE Board Exam.

1. b. approximately 1.0 MHz

2. a. 20 GHz

3. b. a 1500-pair cable

4. b. a light ray directed toward a surface

5. a. separating light into its component frequencies

6. d. The angle is determined by the index of the materials

7. c. the point at which light has gone from the refractive mode to the reflective mode

8. c. acts to help guide the light in the core

9. a. a number which compares the transparency of a material with that of air

10. c. the number of wavelengths each fiber can support

11. a. the higher the speed of light

12. d. the source, the link, and the detector

13. c. 0.5 dB

14. d. Detector sensitivity

15. b. the ratio of the diode output current to optical input power

16. a. 1:10

17. c. field service conditions

18. a. 70 percent of the core diameter and 70% of the fiber NA should be filled with light

19. d. 100/140/0.3

20. c. the total power available minus the attenuation losses

Complete List of MCQs in Electronic Communication Systems by Kennedy

Below are the answers key for Multiple Choice Questions in Chapter 17: Television Fundamentals from the book Electronic Communication Systems by George Kennedy. Make sure to familiarize each and every questions to increase the chance of passing the ECE Board Exam.

1. a. 262 ½

2. d. 30

3. b. 15,750

4. b. 6

5. d. avoid flicker

6. a. sync

7. c. 4.5

8. c. Sweep

9. d. picture carrier

10. c. aspect ratio

11. b. vertical blanking

12. a. done to assist interlace

13. c. help horizontal synchronization

14. b. 3H

15. a. 4.5 MHz

16. d. between grid and cathode

17. b. a clipper

18. d. a sawtooth current

19. c. horizontal output stage

20. d. flyback

21. c. R

22. b. ensure that each beam hits only its own dots

23. a. cuts off the chroma stages during monochrome reception

Complete List of MCQs in Electronic Communication Systems by Kennedy

Below are the answers key for Multiple Choice Questions in Chapter 16: Radar Systems from the book Electronic Communication Systems by George Kennedy. Make sure to familiarize each and every questions to increase the chance of passing the ECE Board Exam.

1. a. 2

2. c. 4

3. d. increased capture area

4. d. is equal to the actual cross-sectional area for small targets

5. b. make the returned echoes easier to distinguish from noise

6. c. increase the maximum range

7. a. pulse width

8. d. the target will appear closer than it really is

9. c. conical

10. d. monopulse

11. b. it does not give the target range

12. b. the target range, but not position

13. a. moving-target plotting on the PPI

14. a. intermediate frequency

15. a. help in subtracting a complete scan from the previous scan

16. b. to vary the PRF

17. d. More accurate tracking of enemy targets

18. c. circuit simplicity

Complete List of MCQs in Electronic Communication Systems by Kennedy

Below are the answers key for Multiple Choice Questions in Chapter 15: Broadband Communications Systems from the book Electronic Communication Systems by George Kennedy. Make sure to familiarize each and every questions to increase the chance of passing the ECE Board Exam.

1. b. repeater amplifiers

2. a. frequency-division multiplex

3. a. occupies the frequency range from 60 to 108 kHz

4. d. interleaves pulses belonging to different transmissions

5. b. the bandwidth of the system

6. d. fed in at a GTE

7. c. because of the Earth’s curvature

8. a. they have less overall phase distortion

9. c. for the shallow shore ends of the cable

10. b. filters for the two directions of transmission

11. b. is not really stationary at all, but orbits the Earth within a 24-hr period

12. d. A satellite earth station must have as many receive chains as there are carriers transmitted to it

13. d. Intelsat

14. c. area codes

15. d. in erlangs

16. a. AND gates

17. a. AND gates

18. a. dividing pulse widths

19. d. stepped index operation

20. d. it does not lend itself to wave

21. b. INTELSAT V

22. a. INTELSAT, b. COMSAT d. INMARSAT

Complete List of MCQs in Electronic Communication Systems by Kennedy

Below are the answers key for Multiple Choice Questions in Chapter 14: Digital Communications from the book Electronic Communication Systems by George Kennedy. Make sure to familiarize each and every questions to increase the chance of passing the ECE Board Exam.

1. d. all of the above

2. c. development of the transistor

3. b. is equal to twice the bandwidth of an ideal channel

4. d. refers to noise

5. b. ASCII

6. c. requiring no part of the signal to be retransmitted

7. d. all of the above

8. a. interconnects data sets and transmission circuit

9. d. are limited to small data networks

10. c. bits per second

Complete List of MCQs in Electronic Communication Systems by Kennedy

Below are the answers key for Multiple Choice Questions in Chapter 13: Pulse Communications from the book Electronic Communication Systems by George Kennedy. Make sure to familiarize each and every questions to increase the chance of passing the ECE Board Exam.

1. a. Morse

2. d. 4

3. c. noise would introduce too many errors

4. a. the maximum rate of information transmission depends on the channel bandwidth

5. a. the channel bandwidth may be increased

6. a. frequency-shift keying

7. b. with a monostable

8. b. Pulse-code modulation

9. c. pulse-code modulation

10. d. pulse-code modulation

11. a. increase the number of standard amplitudes

12. b. maximum capacity of a channel with a given noise level

13. c. PWM

14. c. to protect small signals in PCM from quantizing distortion

15. d. the large bandwidths that are required for it

Complete List of MCQs in Electronic Communication Systems by Kennedy

Below are the answers key for Multiple Choice Questions in Chapter 12: Semiconductor Microwave Devices and Circuits from the book Electronic Communication Systems by George Kennedy. Make sure to familiarize each and every questions to increase the chance of passing the ECE Board Exam.

1. d. to improve the noise performance temperature

2. c. because it cannot operate at room temperature

3. b. is more likely to radiate

4. d. stripline

5. c. higher power-handling capability

6. a. easier integration with semiconductor devices

7. d. quartz crystal

8. a. transmission media like stripline

9. b. lend themselves more easily to integration

10. c. a step-recovery diode

11. b. higher efficiency

12. d. RIMPATT

13. a. Backward

14. d. PIN diode

15. a. Tunnel

16. b. gallium arsenide

17. d. beta of the transistor falls to unity unity

18. d. emitter area must be large

19. c. as an oscillator

20. c. a step-recovery diode must be used

21. b. degenerative amplifier

22. d. f_p – f_i

23. d. provide greater bandwidth

24. a. prevent noise feedback

25. b. yields a low noise figure

26. c. uses a high doping level to provide a narrow junction

27. a. increase the frequency stability

28. b. is available between the peak and valley points

29. c. larger voltage swing

30. a. electron transfer to a less mobile energy level

31. a. has a suitable empty energy band, which silicon does not have

32. b. high noise

33. d. provide frequency adjustments

34. a. a much greater bandwidth

35. c. must be cooled down to a few kelvins

36. c. radar

37. c. is an oscillator

38. d. single-frequency

39. b. using Q spoiling

40. b. prevent atmospheric interference

41. c. lower cost

Complete List of MCQs in Electronic Communication Systems by Kennedy

Below are the answers key for Multiple Choice Questions in Chapter 11: Microwave Tubes and Circuits from the book Electronic Communication Systems by George Kennedy. Make sure to familiarize each and every questions to increase the chance of passing the ECE Board Exam.

1. d. CFA

2. b. BWO

3. a. noise figure increases

4. c. multiple or coaxial leads are used

5. a. is not a good low-level amplifier because of noise

6. a. prevent the oscillations that occur in two-cavity klystrons

7. b. has a greater bandwidth

8. b. returning electrons give energy to the gap oscillations

9. a. prevent mode jumping

10. d. ensure that the electrons will orbit around the cathode

11. d. rising sun

12. b. reduce the axial velocity of the RF field

13. b. prevent oscillations

14. c. avoid the bulk of an electromagnet

15. a. capable of a longer duty cycle

16. d. VTM

17. a. Periodic-permanent magnet

18. b. provide attenuation

19. d. traveling-wave tube

Complete List of MCQs in Electronic Communication Systems by Kennedy

Below are the answers key for Multiple Choice Questions in Chapter 10: Waveguides, Resonators and Components from the book Electronic Communication Systems by George Kennedy. Make sure to familiarize each and every questions to increase the chance of passing the ECE Board Exam.

1. b. they are reflected from the walls but do not travel along them

2. d. they would be too bulky at lower frequencies

3. a. is greater than of free space

4. c. transmission lines use the principal mode of propagation, and therefore do not suffer from low-frequency cut-off

5. c. are less bulky 

6. b. transverse-magnetic

7. d. greater than in the actual direction of propagation

8. d. phase velocity

9. c. the characteristic impedance of the guide becomes infinite

10. d. TE₂,₀

11. b. the resulting impedance can be matched directly to coaxial lines

12. c. to compensate for discontinuities at the join

13. b. E-plane T

14. c. Iris

15. b. waveguide below cutoff

16. c. harmonically related resonant frequencies

17. d. to increase the bandwidth of the system

18. a. a nonconductive with magnetic properties

19. c. garnet

20. a. Curie temperature

21. d. suitable for use as a microwave switch

22. b. to allow the one antenna to be used for reception or retransmission without mutual interference

23. b. lower attenuation

24. c. Coaxial

25. b. ridged

26. c. rectangular waveguide

Complete List of MCQs in Electronic Communication Systems by Kennedy

Below are the answers key for Multiple Choice Questions in Chapter 9: Antennas from the book Electronic Communication Systems by George Kennedy. Make sure to familiarize each and every questions to increase the chance of passing the ECE Board Exam.

1. c. acts as an antenna array

2. a. The rhombic antenna

3. c. log periodic

4. b. Horn

5. b. Protection of personnel working underground

6. d. To prevent reradiation of the local oscillator

7. d. Marconi

8. c. Protection of personnel working underneath

9. d. High gain

10. a. helical

11. b. isotropic antenna

12. a. effective height

13. d. allow the feed to be placed at a convenient point

14. a. reduce the bulk of the lense

15. a. circular polarization

16. d. useful as UHF receiving antennas

17. b. Log-periodic

Complete List of MCQs in Electronic Communication Systems by Kennedy

Below are the answers key for Multiple Choice Questions in Chapter 8: Radiation and Propagation of Waves from the book Electronic Communication Systems by George Kennedy. Make sure to familiarize each and every questions to increase the chance of passing the ECE Board Exam.

1. b. Fading

2. c. they are very reliable

3. d. 12 GHz

4. d. affected by the solar cycle

5. b. to prevent sky-wave and upper ray interference

6. c. frequency diversity

7. a. window

8. d. space waves

9. c. UHF

10. d. tilting

11. b. is due to the transverse nature of the waves

12. b. attenuation

13. a. their frequency

14. a. pass into a medium of different dielectric constant

15. d. may occur around the edge of a sharp obstacle

16. b. ducting

17. d. the Faraday effect

Complete List of MCQs in Electronic Communication Systems by Kennedy

Below are the answers key for Multiple Choice Questions in Chapter 7: Transmission Lines from the book Electronic Communication Systems by George Kennedy. Make sure to familiarize each and every questions to increase the chance of passing the ECE Board Exam.

1. b. a complex impedance

2. d. a short-circuited stub at some specific distance from the load

3. a. depends on the dielectric constant of the material used

4. c. a quarter-wave line

5. c. liable to radiate

6. c. double

7. d. narrow bandwidth

8. b. balun

9. b. Radiation, I²R, and dielectric heating

10. b. a coupling device for matching impedance

Complete List of MCQs in Electronic Communication Systems by Kennedy

Below are the answers key for Multiple Choice Questions in Chapter 6: Radio Receivers from the book Electronic Communication Systems by George Kennedy. Make sure to familiarize each and every questions to increase the chance of passing the ECE Board Exam.

1. c. Greater limiting

2. a. The circuit is always biased in class C, by virtue of the leak-type bias.

3. a. an increase in signal strength produces more AGC

4. b. mixer input must be tuned to the signal frequency

5. b. variable sensitivity

6. d. 2100 kHz

7. a. the linearity is worse than in phase discriminator

8. a. an audio amplifier when the carrier is absent

9. d. Variable sensitivity is used to eliminate selective fading

10. d. it is relatively free of spurious frequency

11. a. reduce the spurious frequency problem

12. d. Phase discriminator

13. b. reducing the effect of negative-peak clipping

14. b. insufficient gain and sensitivity

15. c. is not rejected be the IF tuned circuits

16. d. improve the rejection of the image frequency

17. a. blocking

18. b. the padder capacitor

19. d. to allow adequate frequency coverage without switching

20. d. tracking will be improved

21. c. negative-peak clipping

22. c. Bipolar transistor balanced modulator

23. b. adjacent-channel rejection is more difficult

24. c. it is unaffected by AGC derived from nearby transmissions

25. d. Single-sideband, full-carrier

Complete List of MCQs in Electronic Communication Systems by Kennedy

Below are the answers key for Multiple Choice Questions in Chapter 5: Frequency Modulation from the book Electronic Communication Systems by George Kennedy. Make sure to familiarize each and every questions to increase the chance of passing the ECE Board Exam.

1. c. the discriminator frequency must not be too low, or the system will fail

2. b. the amplitude of any sideband depends on the modulation index

3. d. lies in the different definitions of the modulation index

4. d. Equalization is unnecessary

5. c. 3m_f

6. d. δ

7. b. amplifying the higher audio frequencies

8. b. is decreased

9. c. frequency

10. b. Lower bandwidth is required

11. c. Armstrong modulator

12. c. difference signal modulates the 38 kHz subcarrier

Complete List of MCQs in Electronic Communication Systems by Kennedy

Below are the answers key for Multiple Choice Questions in Chapter 4: Single-Sideband Techniques from the book Electronic Communication Systems by George Kennedy. Make sure to familiarize each and every questions to increase the chance of passing the ECE Board Exam.

1. b. Transmitter circuits must be more stable, giving better reception.

2. c. Single-sideband, suppressed carrier (J3E)

3. d. There are more balanced modulators; therefore the carrier is suppressed better.

4. a. mechanical

5. c. class B RF amplifier

6. a. H3E

7. d. balanced modulator

8. b. simplify the frequency stability problem in reception

9. a. ISB

10. c. TV broadcasting

Complete List of MCQs in Electronic Communication Systems by Kennedy

Below are the answers key for Multiple Choice Questions in Chapter 3: Amplitude Modulation from the book Electronic Communication Systems by George Kennedy. Make sure to familiarize each and every questions to increase the chance of passing the ECE Board Exam.

1. a. 4 V

2. a. linear devices

3. d. 66.66

4. b. prevent excessive grid current

5. b. grid-modulated class C amplifier

6. d. increase by 50 percent

7. a. the lower modulating power required

8. c. is 0.5

9. c. its use avoids receiver complexity.

10. a. 1:3

Complete List of MCQs in Electronic Communication Systems by Kennedy

Below are the answers key for Multiple Choice Questions in Chapter 2: Noise from the book Electronic Communication Systems by George Kennedy. Make sure to familiarize each and every questions to increase the chance of passing the ECE Board Exam.

1. d. transit-time noise

2. b. Impulse noise voltage is independent of bandwidth.

3. d. unchanged

4. a. Input noise voltage

5. c. Atmospheric noise

6. c. Boltzmann’s constant

7. a. noise generated in the receiver

8. c. between 20 to 120 MHz

9. d. calculations are based on RMS values

10. b. noise factor

11. c. Noise is mixers is caused by inadequate image frequency rejection

Complete List of MCQs in Electronic Communication Systems by Kennedy

Below are the answers key for Multiple Choice Questions in Chapter 1: Introduction to Communication Systems from the book Electronic Communication Systems by George Kennedy. Make sure to familiarize each and every questions to increase the chance of passing the ECE Board Exam.

1. b. in the channel

2. a. fundamental and subharmonic sine waves

3. a. reduce the bandwidth used

4. b. predictable in character

5. c. superheterodyne group

6. a. Antenna lengths will be approximately λ/4 long

7. d. the 1840s

8. b. encoding

9. d. person-to-person voice communications

10. a. superimposing a low frequency on a high frequency

Complete List of MCQs in Electronic Communication Systems by Kennedy