Modulation

Modulation is a process that changes the properties of a carrier wave based on the characteristics of an input signal. This process is fundamental in telecommunication and signal processing.

Types of Modulation

There are three primary types of modulation: amplitude, frequency, and phase modulation.

Amplitude Modulation

In amplitude modulation (AM), the amplitude of the carrier wave is varied in proportion to the waveform being sent. This waveform may correspond to sounds to be reproduced by a loudspeaker, or the light intensity of television pixels.

Frequency Modulation

Frequency modulation (FM) is a method of impressing data onto an alternating-current (AC) wave by varying the instantaneous frequency of the wave. This technique is commonly used in broadcasting, especially in the FM radio band.

Phase Modulation

Phase modulation (PM) is a modulation pattern that encodes information as variations in the instantaneous phase of a carrier wave. PM is used in digital music synthesis and telecommunications systems.

Applications of Modulation

Modulation is used in numerous fields such as telecommunications, broadcasting, and data communication. It is also used in systems such as Ethernet to encode data onto a carrier signal.

See Also

• Demodulation
• Modem
• Pulse-code modulation
• Quadrature amplitude modulation

References

Modulation Resources
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