106. Low-orbit satellites are not used for communications because they
A. produce sonic booms
B. travel around the Earth too quickly
C. do not provide 24 hour/day contact to the users on Earth
D. heat up and melt
107. Geosynchronous satellites are always launched in the equatorial plane because it is the only plane which provides
A. 24-hour orbit
B. stationary satellite
C. global communication
D. zero-gravity environs
108. Depending on the technique used, digitized television requires a bit rate between millions
A. 40 and 92.5
B. 25 and 60
C. 30 and 82.5
D. 20 and 40
109. A communication satellite is a repeater between
A. a transmitting station and a receiving station
B. a transmitting station and many receiving stations
C. many transmitting stations and many receiving stations.
D. all of the above
110. The maximum signal propagation time of a geosynchronous satellite transmission is about millisecond.
A.540
B.270
C.135
D.1080
111. A telephone user while talking to a person via a satellite has to wait for reply for about millisecond.
A.100
B.270
C.470
D.540
112. The echo heard by a telephone user on a satellite channel can be removed by using
A. a vocoder
B. a multiplexer
C. echo suppressor
D. digital techniques
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