Modulation allows us to send a signal over a bandpass frequency range. If every signal gets its own frequency range, then we can transmit multiple signals simultaneously over a single channel, all using different frequency ranges. Another reason to modulate a signal is to allow the use of a smaller antenna.

Why is modulation necessary in communication?

To send the message signal, the length of the antenna should be a quarter wavelength of the used frequency. Thus, modulation is required to increase the frequency of the message signal and to enhance its strength to reach the receiver.

Why modulation is necessary in electronic communication system?

1. To reduce the size of the antenna for transmission. 2. To reduce interference of signals so as to maintain the uniqueness of each signal.