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Modem

The receiver must have a device called a demodulator, which performs the reverse function known as ``demodulation''.

The demodulator is tuned to the expected frequency and recovers the modulator, by measuring how much the incoming signal deviates from the expected carrier frequency.

A modem is a modulator and a demodulator.

Before two computers in the Internet can communicate, a modem must be installed at each end of the connection.

Figure 4: Two computers/ modems connected by a transmission line.
\scalebox{0.6}{\includegraphics{eps/twoComputersMode.eps}}

Modems allow for data to be sent between them in both directions.


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``CMPT 165: Review'' by Tamara Smyth, Computing Science, Simon Fraser University.
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Copyright © 2011-12-05 by Tamara Smyth.
Please email errata, comments, and suggestions to Tamara Smyth<tamaras@cs.sfu.ca>
School of Computing Science,   Simon Fraser University