Source: FreeImages.com (Armin Hanisch)

An RF modulator (or radio frequency modulator) is an electric device whose input is a baseband signal that is used to regulate a radio frequency source.

RF modulator History

Before the debut of specialised video trimmer criteria like SCART, TVs were developed to simply accept signals through the aerial connector: signals arise in a TV station, are transmitted through the atmosphere, and so are subsequently received by an antenna and also demodulated inside the TV. When equipment originated that may work with a television recipient because its screen apparatus, like VCRs, DVD players, ancient home computers, and even game consoles, the signal was modulated and sent to the RF input.

The aerial connector is standard on all TV sets, even very old ones. Since later tv layouts consist of composite, S-Video, and component video recorders, which bypass the modulation and demodulation steps, modulators are no longer included as standard equipment, and RF modulators now are largely a third-party solution, bought largely to run newer equipment like DVD players with an older television set.

RF modulator Layout

Technically, RF modulation translates to mixing the info with a carrier signal at an frequency that is standardized.
In united states, RF modulators generally output on channel 3 or 4 (VHF), which might be selectable, although the Atari consoles offer channels 2 and 3. Back in Europe standard modulators usually used station 36 (UHF) automatically, but are often tunable over part or most of the UHF band.

Modulating a TV signal with stereo sound is relatively complex; most low-cost home TV modulators develop a signal with monaural sound. Even some components which have two or more audio controls only combine the left and right sound channels into a mono sound signal. Some used on very early home computers had no solid capability at all. Most more economical modulators (i.e. not intended for expert usage) deficiency vestigial side band filtering.

TV modulators generally comprise analog passthrough, meaning that they simply take input from the apparatus and by the usual antenna input, and the antenna input “passes through” to the TV, using slight weight loss loss due to the additional apparatus. Sometimes the antenna input is always passed while in some other scenarios the antenna input is turned off when the device is outputting a signal, and just the device signal is routed ahead, to reduce disturbance.

RF modulators make a relatively poor picture, as image quality has been lost during both modulation from the origin apparatus, and also the demodulation in the tv screen.

RF Integral modulators

RF modulators are usually integrated in to VCRs, in game consoles up to the fourth generation, and in 8- and also 16-bit home computers.
Several systems were given an external modulator unit which attached to both device and also into the antenna jacks of a tv. 1 reason to it is a device that ignites an RF signal must in general be certified by regulatory governments–including as for instance the U.S. Federal Communications Commission (FCC) — and so by with an external RF modulator, only the modulator itself needed to become certified, instead of the entire game procedure.

Multi channel RF modulators are commonly used in home caked supply. These devices have multiple video and audio inputs and one RF output. The modulator is then programmed to broadcast the signs on a particular frequency. That RF air is subsequently received by the attached television. After the TV is tuned to the programmed station, the video and audio signal of this origin apparatus is accessed. RF modulation may get difficult at a CATV program. High pass, low pass, and notch filters must be used to obstruct certain frequencies, or channels, so your modulator can broadcast the output signal of this source device on that channel.

Sound RF modulators are employed in non invasive car sound so as to add devices like CD changers without requiring dashboard hardware upgrades. As an instance, a portable CD player’s headphone jack is on the modulator, which sparks a low-power radio signal that’s played through the car radio. Car FM modulators suffer with lack of quality and interference problems. Later devices that may make use of these kinds of modulators would be iPods and similar mobile media players.