Modulation at the Transmitter:
1. Carrier Wave: The transmitter generates a continuous radio wave, known as the carrier wave, at a specific frequency allocated for the radio station.
2. Audio Processing: The audio signal (speech, music, etc.) is processed to extract its amplitude variations.
3. Amplitude Modulation (AM): The carrier wave's amplitude is varied in accordance with the amplitude variations of the audio signal. This process imprints the audio information onto the carrier wave.
Transmission and Reception:
1. Radiation: The modulated radio wave, containing both the carrier wave and the superimposed audio information, is radiated by the transmitter's antenna into the air.
2. Reception: Receiving devices (radios) capture the modulated radio waves through their antennas.
Demodulation at the Receiver:
1. Signal Capture: The radio's antenna receives the modulated radio waves and converts them into electrical signals.
2. Detection: The receiver detects the amplitude variations in the incoming signal. These variations correspond to the original audio signal that was impressed on the carrier wave during modulation.
3. Extraction: The detected amplitude variations are filtered and amplified to extract the original audio information.
4. Audio Output: The extracted audio signal is then amplified further and sent to the speaker of the radio, where it is converted back into sound waves, allowing listeners to hear the audio content.
By modulating the amplitude of the carrier wave and demodulating it at the receiver, AM radio enables the transmission and reception of audio signals, allowing us to enjoy a variety of radio programs, news, and music across various radio stations.