RF modulator

An RF modulator (or radio frequency modulator) is an electronic device whose input is a baseband signal which is used to modulate a radio frequency source.

RF modulators are used to convert signals from devices such as media players, VCRs and game consoles to a format that can be handled by a device designed to receive a modulated RF input, such as a radio or television receiver.

Prior to the introduction of specialised video connector standards such as SCART, TVs were designed to only accept signals through the aerial connector: signals originate at a TV station, are transmitted over the air, and are then received by an antenna and demodulated within the TV. When equipment was developed which could use a television receiver as its display device, such as VCRs, DVD players, early home computers, and video game consoles, the signal was modulated and sent to the RF input connector.

The aerial connector is standard on all TV sets, even very old ones. Since later television designs include composite, S-Video, and component video jacks, which skip the modulation and demodulation steps, modulators are no longer included as standard equipment, and RF modulators are now largely a third-party product, purchased primarily to run newer equipment such as DVD players with an old television set.

Technically, RF modulation usually means combining the data with a carrier signal at a standardized frequency. Either amplitude or frequency modulation may be used, as required by the receiving equipment.

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