ABSTRACT
A modem is a telecommunication device that provides long-distance data transfer over a transmission line to reach another remote device. Long-distance data transfer is based on the fact that the data stream is modulated into the robust carrier suitable for remote transmission, which is then demodulated on the receiving end. Basically, data are inserted into some of the carrier parameters, to be later extracted and retrieved. Modulation techniques could be different, i.e., different carrier parameters could be affected: amplitude, frequency, phase, or other, and they identify the type of a modem. Each modem consists of two parts:
• Transmitter, or modulator, which provides a modulation of input data into the carrier suitable for remote data transfer.
