& Supply the missing word(s) in each statement.
Choose the letter that best answers each question.
1. The three major fields of electronics are _____. The largest is the _____field.
2. Communication is defined as the process of _____.
3. Most human communication is _____ even though there is a glut of _____ communication.
4. Two major barriers to human communication are _____.
5. Electronic communications came into being in the _____.
6. The three main elements of any communications system are _____.
7. The three major types of communications paths are_____.
8. The _____ converts the message into a form compatible with the selected medium.
9. The _____ converts the message from the medium into a form understandable by a human.
10. Undesirable interference in communications _____ is which is added to the signal in the _____.
11. The communications media greatly _____ and the information _____ signal.
12. Three common sources of interference are _____.
13. One-way communications is called_____. An example is _____.
14. Simultaneous two-way communications is called _____. An example is _____.
15. Two-way communications where each parry takes turns transmitting is referred to as_____.
16. Voice and video signals are continuous _____ voltages.
17. On/off or coded signals are referred to _____ as signals.
18. Voice and video signals may be transmitted digitally if they are first passed through a(n) _____.
19. An original voice, video, or data voltage is called the _____ signal.
20. To make the transmitted signal compatible with the medium, the process of _____ must be used where the _____ signal is impressed upon a higher-frequency signal called the_____.
21. Recovering the originally transmitted signal is called_____.
22. The process of transmitting two or more baseband signals simultaneously over a common medium is called _____.
23. Two methods of transmitting visual data over the telephone network are_____.
24. A common household remote-control unit is the_____.
25. The signaling of individuals at remote locations is called _____.
26. Performing, recording, and analyzing measurements at a distance is done with _____ equipment.
27. Radio astronomy is based on the fact that stars and other heavenly bodies emit_____.
28. List four ways radio is used in the telephone system _____.
29. Radar is based on the use of _____ radio signals.
30. Underwater radar is called _____.
31. The two types of sonar are _____.
32. The radio communications hobby is called _____.
33. Computers exchange digital data over the telephone network by using devices called _____.
34. Limited interconnections of PCs and other computers in offices or buildings are called _____.
35. Signals that travel through free space for long distances are called _____.
36. Radio waves are made up of _____ fields.
37. A signal with a frequency of 18 MHz has a wavelength of _____ m.
38. Common power line frequencies of _____ and _____ Hz are in the _____ range.
39. Audio signals are not transmitted by electromagnetic waves because
a. Antennas would be too long.
b. Audio signals do not radiate.
c. Simultaneous transmissions would interfere.
d. The frequency is too low.
(Choose all that apply.)40. The human hearing range is approximately _____ to _____ Hz.
41. The frequency range of the human voice is _____ to _____ Hz.
42. True or false. Radio transmissions do not occur in the VLF and LF ranges.
43. AM broadcast stations are in the _____ range.
44. HF signals are also called _____.
45. TV (channels 2 to 13) and FM broadcasting is in the _____ part of the spectrum.
46. List five major uses of the UHF band.
47. A frequency of 1 GHz is the same as _____ MHz.
48. Frequencies above 1 GHz are called _____.
49. The SHF and EHF ranges are primarily used by _____ communications.
50. The frequencies just beyond the EHF range are called _____ waves.
51. One micron is the same as _____ m.
52. Infrared signals are usually derived from _____ sources.
53. The spectrum range of infrared signals is _____ to _____ mm.
54. One angstrom is equal to _____ mm.
55. The visible light range is from _____ to _____Ǻ.
56. Light signals use two mediums in electronic communications _____.
57. The spectrum space occupied by a signal is called the _____.
58. The new signals above and below the carrier frequency produced by the modulation process are called _____.
59. A signal occupies the frequency range from 1.050 to 1.175 MHz. Its bandwidth is _____ kHz.
60. Wide-bandwidth signals must be transmitted at _____ frequencies.
61. Percentage wise, there is less spectrum space at the _____ frequencies.
62. Many communications electronics techniques are designed in order to conserve _____.
63. Electronic communications in the United States is regulated by a set of laws called the _____.
64. The regulatory body for electronic communications in the United States is the _____.
65. Government and military communications are coordinated by the _____.
The electromagnetic spectrum is managed worldwide by the_____ organization.
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