ECE Board Exam.Review Nov.1996

1. Which frequency band is the standard AM radio broadcast?
A. HF
B. UHF
(C) MF
D. VHF
2. A system that performs parallel-to-serial and serial-to-parallel conversion of data link.
A. DCE
(B) DTE
C. Modem
D. PC
3. The line control unit (LCU) operates on the data in digital form.
A. Data communications equipment (DCE)
B. UART
C) Modem
(D) Data terminal equipment
4. Quantization noise is caused by
A) binary coding techniques
B. serial transmission errors
C. the synchronization between encoder and decoder
(D) the approximation of the quantized signal
5. Speaker is a device that ______.
(A) convert current variation into sound waves
B. none of these
C. concert electrical energy to mechanical energy
D. concert sound waves into current and voltage
6. An object farther from a converging lens than its focal point always has an _____ image.
A. virtual
B. the same in size
(C) inverted
D. smaller size
7. The loss in signal power as light travels down a fiber is
(A) attenuation
B. propagation
C. absorption
D. scattering
8. Energy that has neither been radiated into space nor completely transmitted
A. Captured waves
B. Incident waves
(C) Standing waves
D. Modulated waves
9. One of the reasons why FDM is being replaced by TDM is
(A) noise is amplified with voice when an FDM system is used
B. it is difficult to place channel side by side
C. there is more time than frequency
D. most available frequencies has been used
10. Which determine the number of sideband components in FM?
A. Modulation frequency
(B) Modulation index
C. Carrier frequency
D. All of these
11. When one stations is designated as master and the rest of the station are considered slaves message handling is _____.
(A) polling
B. WAN
C. LAN
D. OSI
12. How many satellite orbital slots are requested by the Philippine government from ITU?
A. 2
(B) 6
C. 5
D. 3
13. The output of a balanced modulator is _____.
(A) LSB and USB
B. LSB
C. USB
D. Carrier
14. A special service circuit connecting two private branch exchanges (PBX)
A. Phantom line
B. Private line
(C) Tie trunk
D. Tandem trunk
15. What is the baseband frequency of standard FDM basic supergroup?
(A) 312 to 522 kHz
B. 300 to 600 kHz
C. 60 to 2540 kHz
D. 60 to 108 kHz
16. What is the data rate of the ISDN Basic access B Channel?
A. 192 kbps
B. 32 kbps
(C) 64 kbps
D. 144 kbps
17. What is the transmission rate of a GSM cellular system
A. 64 kbps
B. 240 kbps
C. 128 kbps
(D) 270 kbps
18. Pulse carrier at the radio of 8000 pulses/sec is amplitude modulated by an analog signal, this type of modulation is
(A) PAM
B. ADM
C. DM
D. PCM
19. Collects very weak signals from a broadcast satellite.
(A) Satellite dish
B. LNB
C. Yagi-Uda antenna
D. Satellite receiver
20. A seven-bit character can represent one of _____ possibilities.
A. 14
B. 64
(C) 128
D. 7
21. The maximum power suggested by KBP on 919-1312 Am broadcast station in Metro Manila is
A. 10 kW
(B) 20 kW
C. 15 kW
D. 5 kW
22. When the clearance above the obstruction is equal to the radii of even fresnel zone at the point of reflection the RSL is:
A. remain the same
B. above threshold
(C) decreased
D. increased
23. A______ interconnects LAN having identical protocols at the physical and data link layers.
A. all of these
(B) Bridge
C. router
D. gateway
24. Both frequency and phase modulation utilize ______ modulation.
A. phase
B. AM and FM
C. digital
(D) angle
25. An invitation from the primary to secondary to transmit a message.
A. Retransmission
B. Selection
C. Reuse
(D) Polling
26. An agency of the United Nations that formulates standards and recommended practices for all civil aviation.
(A) ICAO
B. CAA
C. IATA
D. ATO
27. The transformer signal coding method for T1 carrier is
A. binary
B. NRZ
C. Manchester
(D) bipolar
28. When the value of k increases, the effective result is ____ of the equivalent curvatures.
A. downward curvatunes
(B) flattening
C. bulging
D. sharp curvature
29. An electromagnetic wave consist of
A. a magnetic field only
(B) both electric and magnetic fields
C. an electric field only
D. non magnetic field only
30. Satellite signal transmitted from a satellite transponder to earth’s station.
A. Vertically polarized
B. Uplink
(C) Downlink
D. RHCP
31. Which stands for dB relative level?
A. dBm
B. dBm
(C) dBr
D. dBa
32. What is the maximum color TV bandwidth?
A. 1.6 MHz
B. 0.5 MHz
C. 1.0 MHz
(D) 1.3 MHz
33. Digital modulation technique used in modems.
A. ASK
(B) PSK
C. FSK
D. all of these
34. Which of the following is not a baseband signal of modulation.
(A) RF carrier
B. Video system
C. Audio signal
D. Binary coded pulses
35. When was the UHF (14-83) of television were added?
A. 1852
B. 1904
C. 1947
(D) 1952
36. Multiplexing in a time division multiplexer occurs based upon
A. the position of a frame within a group of frames
(B) the positioning of data within a frame
C. the priority assigned to a connected device
D. the activity of a connected device
37. Which is the non-resonant antenna?
A. Broadside antenna
B. Folded dipole
(C) Rhombic antenna
D. End fire array
38. The first commercial satellite.
A. Explorer
B. Sputnik
C. Telstar
(D) Early bird
39. What band does VSAT first operate?
A. X-band
(B) C-band
C. Ku-band
D. L-band
40. The wavelength of light has no role in
A. diffraction
B. interference
C. resolving power
(D) polarization
41. Luminous efficiency is least for a
A. mercury vapor lamp
(B) low-wattage light bulb
C. high-wattage light bulb
D. fluorescent tube
42. What is the equivalent output of a circuit in dBm, if it is has an output of 10 watts?
A. 145.6 dB
B. 138.5 dB
C. 135.5 dB
(D) 140.89 dB
43. Satellite engine use
A. liquid fuel
B. jet propulsion
(C) ion propulsion system
D. solar jet
44. Electromagnetic waves travel at ____ in free space.
(A) 300,000 km/sec
B. 100,000 km/sec
C. 400,000 km/sec
D. 200 km/sec
45. Codes must be
(A) agreed upon in advance between sender and receiver
B. eight bit per character
C. the same in all modern computer
D. either seven or eight bits per character
46. What is the stage of the sand becoming a silicon?
A. Hot
B. Gas
C. Liquid
(D) Molten
47. Noise reduction system used for film sound in movie.
A. dBx
(B) dolby
C. dBa
D. dBm
48. Combination of modulator, channel, and detector.
A. Tranceiver
(B) Discrete Channel
C. T/R channel
D. Transponder
49. What is the type of emission used by standard AM radio broadcast?
A. A0
B. F3
(C) A3
D. A5C
50. Top loading is used in an antenna in order to increase its _____.
A. input capacitance
B. beamwidth
C. bandwidth
(D) effective height