ECE Board Exam.Review Nov .97

1. Extra-terrestial noise is observable at frequencies from
A. 0 to 20 kHz
B. Above 2 GHz
(C) 8 to 1.43 GHz
D. 5 to 8 GHz
2. Band light waves, that are too short to be seen by human eye.
A. Visible
B. Infrared
(C) Ultraviolet
D. Amber
3. Two wires that are bent 90 degrees apart.
A. Hertz
(B) Dipole
C. Log-periodic
D. Rhomic
4. The first symbol in the designation of radio emission under the ITU rules refers to
A. nature of signal(S) modulating the main carrier
B. type of information to be transmitted
C. bandwidth
(D) type of modulation of the main carrier
5. Operating method in which the transmission is made alternately in each
direction of a telecommunication channel.
A. Semi-duplex operation
B. Duplex operation
(C) Half-duplex operation
D. Simplex operation
6. Production of radiation by a radio transmitting station.
A. Monitoring
(B) Emission
C. Radiation
D. Transmission
7. The third symbol in the designation of radio emission under the ITU rules refers to
A. type of the modulation of the main carrier
B. bandwidth
C. nature of the signal(s) modulating the main carrier
(D) type of information to be transmitted
8. A form of telecommunication for the transmission of transient images to fixed or
moving objects.
A. E-mail
(B) Television
C. Radio
D. Internet
9. Radiation pattern of a discone.
A. Unidirectional
B. Bidirectional
(C) Omnidirectional
D. Figure of eight
10. Another SEG function that allows a person to be superimposed on another scene.
A. Visual effect
B. Wiper
(C) Chroma keying
D. Special effect generation
11. What signal-to-noise ration is required for satisfaction telephone services?
(A) 50 dB
B. 30 dB
C. 40 dB
D. 20 dB
12. The use of telecommunication for automatic indicating or recording measurement
at the distance from the measuring instrument.
A. monitoring
B. Tracking
(C) Telemetry
D. Telecommand
13. The standard deviation of the variation in the transmission loss of a circuit should not exceed
A. 3dB
(B) 1 dB
C. 5 dB
D. 0.5 dB
14. Noise use by the thermal agitation of electrons is resistance.
A. All of these
B. Thermal noise
C. Johnson’s noise
(D) White noise
15. Unity gain antenna.
(A) Isotropic
B. Rhombic
C. Half-wave dipole
D. Dummy
16. The series of periodically recurrent pulses is modulated amplitude by the corresponding
instantaneous samples.
A. PFM
B. PWM
C. PDM
(D) PAM
17. This type of transmission permits communication in the frequency range from 30 to 60 MHz and
over distances from about 1000 to 2000 km.
A. Troposcatter
(B) Ionospheric scatter
C. Ducting
D. Microwave
18. A region in front of a paranoid antenna.
A. Transmission zone
(B) All of these
C. Fraunhofer
D. Fresnel
19. Designates the sensation of low or high in the sense of the base and treble.
A. Frequency
B. Intensity
(C) Pitch
D. SPL
20. A good example of a pilot tone system used in commercial frequency
modulation stations.
A. FDM
B. Time division
(C) Stereo multiplexing
D. Frequency modulation
21. Emission on a frequency or frequencies immediately outside the necessary bandwidth which
result from the modulation process except spurious emission.
A. radiation
B. Noise
(C) Out of the band
D. Interference
22. A helical antenna is used for satellite tracking because of _____________.
A. broad bandwidth
B. good front-to-back
C. maneuverability
(D) circular polarization
23. Background noise is the same as the following except
(A) impulse noise
B. white noise
C. thermal noise
D. Gaussian noise
24. An electric equipment used to measure standing wave ratio.
(A) Reflectometer
B. Waveneter
C. Altimeter
D. Multimeter
25. A single sideband emission in which the degree of carrier suppression enables
the carrier to be reconstituted and to be used for demodulation.
(A) Reduce carrier single sideband emission
B. Half carrier single sideband emission
C. Full carrier single sideband emission
D. Standard single sideband emission
26. Station in the mobile service not intended to be used while in motion.
A. Coast station
B. Fixed station
C. Base station
(D) Land station
27. The electric field lines in a plane perpendicular to the earth’s surface.
A. Elliptical polarization
B. Circular polarization
C. Horizontal polarization
(D) Vertical polarization
28. A digital carrier facility used to transmit a DSI-formatted signal at 1.544 Mbps.
A. T2
(B) T1
C. T4
D. T3
29. 12 voice channels are sampled at 8000 sampling rate and encoded unto 8 bit PCM word.
Determine the rate of the data stream.
A. 354 kbps
B. 750 kbps
(C) 768 kbps
D. 640 kbps
30. The most common device used as a alight detector in fiber optic communication system.
A. LED
B. Darlington phototransistor
(C) APDs
D. PIN diode
31. If a fiber optic system has a rise time of 38.55 ns, the source rise time is 12 ns and the detector rise time
is 12 ns, what is the cable rise time?
(A) 34.61 ns
B. 14.55 ns
C. 53.55 ns
D. 26.25 ns
32. Nominal voice channel
A. 20 to 20 kHz
B. 16 to 16 kHz
C. 3 to 3 kHz
(D) 4 kHz
33. Two or more antennas separated by 9 wavelengths are used.
A. Hybrid diversity
(B) Space diversity
C. Polarized diversity
D. Frequency diversity
34. nif stands for
A. narrow intermediate frequency
B. noise interference figure
(C) noise improvement factor
D. non-intrinsic figure
35. Any small element of space in the path of a wave may be considered as a source of
secondary wavelet.
A. De Morgan’s Principle
B. Faraday’s Law
(C) Huygen’s Principle
D. Fresnel’s Law of optics
36. Modulation in which the modulated wave is always present.
A. Carrier modulation
B. Front-end
(C) Continuous modulation
D. Log-periodic modulation
37. Atmospheric noise is less at severe frequencies above
A. audio level
(B) 30 MHz
C. 10 GHz
D. 1 GHz
38. At height about 180 km above the earth exist only during daylight.
A. F2 layer
B. D layer
C. E layer
(D) F1 layer
39. Radiation characteristics of a dipole.
A. Figure of eight
B. Omnidirectional
(C) Bidirectional
D. Unidirectional
40. Determine the gain of a 6 ft. parabolic dish operating at 1800 MHz.
A. 30 dB
B. 11.2 dB
C. 15.5 dB
(D) 28.17 dB
41. An electromagnetic wave is _________ polarized when the electric field lies wholly in one plane
containing the direction of propagation.
A. horizontally
(B) linearly
C. circularly
D. vertically
42. A device that reduces the intensity of light in fiber optics communication systems.
A. Reducer
B. Quality factor
(C) Optical attenuator
D. Compressor
43. Propagation mode of microwave in a waveguide is known as ________.
A. TM
(B) TE
C. SW
D. TEM
44. A convenient method of determining antenna impedance.
A. Stub matching
B. Reactance circle
(C) Smith chart
D. Trial and error
45. Which of the following falls under the high frequency band of the radio spectrum?
(A) 8.2345 MHz
B. 150.50 MHz
C. 2.4555 MHz
D. 35.535 MHz
46. The electric field lies in a plane parallel to the earth’s surface.
A. Elliptical polarization
(B) Horizontal polarization
C. Vertical polarization
D. Circular polarization
47. The use of telecommunication for the transmission of signals to initiate, modify or terminate
functions of equipment at a distance.
A. Tracking
B. Telemetry
(C) Telecommand
D. Space telemetry
48. The product of the power supplied to the antenna and its gain relative to a half-wave
dipole in a given direction.
A. Peak envelope power
(B) ERP
C. Rated power
D. Carrier
49. Width measured in degrees of a major lobe between end of the lobe at which the relative
power is one half (-3dB) its value from the peak of the lobe.
A. Bandwidth
B. Wavelength
C. Radiation
(D) Beamwidth
50. The sinusoidal carrier is pulsed so that one of the binary states represented by a carrier
while the other is represented by its absence.
A. FSK
(B) ASK
C. PSK
D. QAM