Signal modulation

Uncommon card · No. 150936

Signal modulation is the process of varying one or more properties of a periodic waveform in electronics and telecommunication for the purpose of transmitting information. The process encodes information in the form of a message signal modulated onto a carrier signal to be transmitted. For example, the message signal might be an audio signal representing sound from a microphone, a video signal representing moving images from a video camera, or a digital signal representing a sequence of binary digits, a bitstream from a computer. Carrier waves are necessary when the frequency of the message is too low to practically transmit. Generally, receiving a radio wave requires a radio antenna with a length that is one-fourth of the wavelength of the transmitted wave. For low-frequency radio waves, wavelength is on the scale of kilometers and building such a large antenna is not practical. Another purpose of modulation is to transmit multiple channels of information through a single communication...

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