Modulation:
Modulation is a technique used to convert a low frequency message signal to a higher frequency modulated signal using a higher frequency carrier.
Definition:
Modulation is the process of changing the parameters of the carrier signal, in accordance with the instantaneous values of the modulating signal.
Signals in the Modulation Process:
1. Message or Modulating Signal :-
The signal which contains a message to be transmitted is called as a message signal. It is a baseband signal, which has to undergo the process of modulation, to get transmitted. Hence, it is also called as the modulating signal.
Baseband signal: Baseband refers to the original frequency range of a transmission signal before it is converted, or modulated, to a different frequency range.
2. Carrier Signal :-The high frequency signal which has a certain phase, frequency, and amplitude but contains no information is called a carrier signal. It is an empty signal. It is just used to carry the signal to the receiver after modulation.
3. Modulated Signal:-
The resultant signal after the process of modulation is called as the modulated signal. This signal is a combination of the modulating signal and the carrier signal.