Up in the sky there are hundreds of satellites; in fact, there are currently an estimated 3600 satellites orbiting the earth. There are many usages for satellites, including weather satellites, navigation, TV broadcast, earth remote sensing, and communications. Members of the latter category are used to convey communication signals across large distances than cannot be easily linked by a direct line or cable.
Most communication satellites today actually act like a mirror: they receive signals from one station on earth, amplify these signals, and send them on to other locations on earth. The point to note here is that, other than amplifying the signal in some cases, most satellites do not perform any actual processing on the received signals
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