Demodulation

Demodulation (/diːˈmɒd.jʊˌleɪ.ʃən/) is the process of extracting the original information-bearing signal from a carrier wave. The term is used in the field of Telecommunications and Signal Processing.

Etymology

The term 'Demodulation' is derived from the Latin word 'de-' meaning 'from' or 'off', and 'modulation', which in this context refers to the process of varying the characteristics of a carrier signal in accordance with the information being sent.

Process

In demodulation, the carrier signal is altered to produce the original or baseband signal. This is usually achieved by using a demodulator, a device that is designed to perform this function. The demodulator takes the modulated carrier signal and adjusts its frequency or phase to match that of the original signal, effectively 'removing' the carrier and leaving the original signal.

Types of Demodulation

There are several types of demodulation, including amplitude demodulation, frequency demodulation, and phase demodulation. Each type corresponds to the method of modulation used to encode the signal onto the carrier.

Amplitude Demodulation - This is used when the original signal was encoded using amplitude modulation. In this process, the amplitude of the carrier signal is adjusted to match that of the original signal.

Frequency Demodulation - This is used when the original signal was encoded using frequency modulation. In this process, the frequency of the carrier signal is adjusted to match that of the original signal.

Phase Demodulation - This is used when the original signal was encoded using phase modulation. In this process, the phase of the carrier signal is adjusted to match that of the original signal.

Related Terms

Modulation - The process of varying a carrier signal in order to use that signal to convey information.
Carrier Signal - A signal that can be varied in terms of amplitude, frequency, phase, or some other property in order to convey information.
Amplitude Modulation - A type of modulation where the amplitude of the carrier signal is varied in accordance with the information being sent.
Frequency Modulation - A type of modulation where the frequency of the carrier signal is varied in accordance with the information being sent.
Phase Modulation - A type of modulation where the phase of the carrier signal is varied in accordance with the information being sent.