question_answer

Define the term modulation. Name three different types of modulation used for a message signal using a sinusoidal continuous carrier wave. Explain the meaning of any one of them.                                     

Answer:

                Modulation. It is the process of varying some characteristic (amplitude, frequency or phase angle) of the high frequency carrier wave in accordance with the instantaneous value of the low frequency message signal. Types of modulation: (i)Amplitude modulation (ii)Frequency modulation (iii) Phase modulation. Amplitude modulation, m this process the modulating wave (message signal) is super imposed on a high frequency carrier wave such that the amplitude of the modulated wave varies as the amplitude of the modulating wave. Frequency of the modulated wave is equal to the frequency of the carrier wave.