question_answer

A radio broadcast is transmitted using amplitude modulation at a carrier frequency of 680 kHz. Explain the meaning of each of the italicized words.

Answer:

                When the message signal is superimposed on a carrier wave of frequency 680 kHz, the amplitude of the resultant modulated wave varies in proportion with the instantaneous value of the message signal. The amplitude of the modulated wave varies at the frequency \[({{f}_{m}})\] of the message signal while its frequency remains equal to that of the carrier wave (680 Hz).