This is the Coaching materials in Broadcasting Part 1 as one topic in ECE Board Exam taken from various sources including but not limited to past Board Examination Questions in Electronic System and Technologies (EST), Communications Books, Journals and other Communications References. This particular Coaching Notes in Communications Engineering has random Questions and Answers in random topics. Make sure to familiarize this review notes to increase the chance of passing the ECE Board Exam.
Broadcasting Coaching Materials Part 1
1. FM broadcast receivers in the 88 MHz to 108MHz have an intermediate frequency (IF) nominally at
10.7 MHz *
2. The AM broadcast band in the Philippines is
535 kHz to 1605 kHz*
3. If the final amplifier output power of a TV broadcast station is 4kW,the antenna transmission loss is 400 watts, and the antenna power gain is 10, the effective radiated power is
35kW.
4. What type of emission used in video part of television transmission?
A5*
5. What is the purpose of the blanking pulses in a television receiver?
Cuts off the cathode ray tube beam during retrace *
6. How wide a frequency band must the IF amplifier of an FM broadcast receiver pass?
150 kC*
7. What is the frequency swing of an FM broadcast transmitter modulated 80 percent?
60 kC*
8. What is the function of quartz crystal in a radio transmitter?
To stabilize the frequency of the transmitting system*
9. To cut off dangerous voltages when the cabinet of a transmitter is opened, what device is used?
Interlock switch*
10. Transmitter maintained only for transmitting the regular programs of broadcast stations in case of failure of the main transmitter is the
auxiliary transmitter.
11. The frequency tolerance allowed in international broadcast stations is
±2 kHz*
12. Auxiliary transmitter of a regular broadcast station must be tested at least
once each week*
13. What do you call of the device which is used to derive a standard frequency of 10 kilocycles from a standard-frequency oscillator operating on 100 kilocycles?
Multivibrator*
14. What is the oscillator frequency of an FM station using two doublers, one tripler, and a quadrupler, whose center frequency is 105.6MHz?
2.2 MHz*
15. The field intensity of the antenna of a broadcast station is normally measured in
microvolts per meter*
16. The radio wave propagated from high frequency broadcast station which reaches more than 4000km is called
sky wave*
17. What is the purpose of station call sign?
Identification of station*
18. What is the crystal frequency in a transmitter having three doubler stages and output frequency of 8000kHz?
1000 kHz*
19. Why should a transmitter be tuned initially at reduced power?
To prevent damage to components*
20. What is the purpose of putting crystal oscillator in a constant temperature oven?
To stabilize the oscillator frequency*
21. A crystal oscillator is used to generate the carrier wave in transmitter because it
has good frequency stability*
22. Too much loading of an oscillator may result in
poor frequency stability*
23. In a frequency modulated receiver, the function of the discriminator is to
separate audio signal from the IF*
24. In broadcast transmitters, modulation in the oscillator stage is rarely used because
it is liable to cause frequency instability*
25. The stability of transmitter frequency is best maintained by
using crystal oscillator as frequency operator*
26. The emission symbol for television broadcast is
A5*
27. To maintain a stable frequency, crystal in the oscillator stage are
enclosed in crystal ovens*
28. A system of telecommunication set-up for the transmission of speech, or in some cases other sounds is
telephony*
29. The type of emission for FM stereo (multiplex) broadcasting is
F8E*
30. The width of a television broadcast channel is
6MHz*
31. The spare radio equipment is normally termed as
auxiliary equipment*
32. The function of a quartz crystal in a radio transmitter is
to keep the transmitter on its assigned frequency within the allowed frequency tolerance*
33. In FM transmitter the amplitude of the antenna current
remains essentially constant during the process of modulation*
34. The squelch circuit in a radio communication receiver is used
to reduce inherent noise developed in the receiver during the absence of signal frequency*
35. A _____ is essentially a frequency stabilizer. It serves as a voltage amplifier stage to isolate the crystal oscillator from the radio frequency amplifier circuit.
buffer amplifier
36. Undesired oscillations developed in a radio frequency amplifier circuit as some frequency higher than the normal operating frequency.
Parasitic oscillation*
37. _____ is used to load a transmitter for testing purposes without radiation.
Dummy antenna*
38. The expression “positive temperature coefficient” as applied to a quartz crystal means
that the frequency of the crystal varies directly with the temperature*
39. The expression “negative temperature coefficient” as applied to a quartz crystal means
that the frequency of the crystal varies indirectly with the temperature*
40. the video signal transmitted on a TV program employs
amplitude modulation*
41. The sound transmitted on a TV program employs
frequency modulation*
42. In broadcast studios, a zero VU indicates how much percent modulation?
100*
43. This amplifier is used to isolate oscillator from power amplifiers.
Buffer amplifier*
44. A power line filter for rejecting RF interference has
RF bypass capacitors in shunt across the power line*
45. In a broadcast station, the audio peak limiters are used to
prevent the modulation percentage of the transmitter to be exceeded*
46. What is the local oscillator frequency in commercial AM broadcast if it is equal to 455 kHz?
955 to 2055 kHz.
47. Listing of the date and time of events, programs, equipments, tests, malfunctions and corrections in communications system
Log
48. What is the purpose of an indirectly-heated cathode in a cathode ray tube?
Beam production
49. Which of the following is not a low-impedance microphone?
Crystal
50. Facsimile permits remote duplications of which of the following items?
Map, Pictures, Printed Page
51. A measure of how well the receiver can respond to very weak signals.
Sensitivity
52. The FM broadcast band is from
88 to 108 kHz.
53. The type of emission used by standard AM radio broadcast.
A3
54. The standard AM radio broadcast belongs to which frequency band?
MF
55. What is the allowable frequency deviation of a commercial FM broadcast band?
75 kHz
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