In this note, we are going to learn about a topic called “What is Demodulation?” and Necessity of Demodulation. Welcome to Poly Notes Hub, a leading destination for engineering notes for diploma and degree engineering students.

Author Name: Arun Paul.

What is Demodulation?

The method of recovering an audio signal from modulated waves is known as demodulation detection.

At the broadcasting station, modulation is used to transmit an audio signal over a longer distance to a receiver. When the radio receiver picks up the modulated waves, the audio signal must be recovered from them. This process, known as demodulation, occurs in the radio receiver.

Necessity of Demodulation

It was previously said that an amplitude modulated wave consists of carrier and sideband frequencies. The audio signal is encoded in sideband frequencies, which are radio frequencies. If the modulated wave after amplification is delivered directly to the speaker, as shown in Fig., no sound is produced. The speaker’s diaphragm is incapable of responding to such high frequencies. Before the diaphragm can move in one way, the quick reversal of current causes it to move in the opposite direction, resulting in no movement at all. Consequently, sound will be heard.