**2.1.2 Modulator**

Modulation is a process of facilitating the transfer of information over a medium. Modulation is the process of mapping of the information on changes in carrier phase, frequency or amplitude or combination. Modulation schemes such as PSK (BPSK, QPSK, 8- PSK, 16-PSK, 32-PSK) or QAM (8-QAM, 16-QAM, 32-QAM, 64-QAM) are used.
