QAM Modulator and Demodulator combine two amplitude modulation signals into a single data transfer channel:
1. Technique of modifying any one characteristic (amplitude, frequency, or phase) of a relatively high-frequency carrier signal in proportion to the instantaneous value of the modulating signal or message signal is known as modulation.
2. In demodulation, signals from the transmitter enter the demodulator and are divided into two signals that are sent into separate mixers. The local oscillator generates needed frequency demodulation signals, which are in-phase and quadrature signals.