RF Modulation, Providing Easy Access to Distributed Video

RF Modulation, Providing Easy Access to Distributed Video
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By Steve Briggs

Balance in RF modulation is an important concept for just about any audiovisual technician to master.  Especially if they are going to be getting into home technology integration or want to become a home theater installer.  Clients are asking for the ability to watch video on multiple televisions throughout the home utilizing the home’s existing wiring.  This video could be a source such as their Blu-ray player, Satellite Receiver (high definition modulation over Co-ax cable is available and reliable) or standard analog devices such a basic security camera outside the front door.  Proper AV training can help inform the technician about which devices are available for this application.  Signal injection and modulation play an important role in this process as well as balancing of the signal that is being split up and fed to different sources.  If the modulator being used does not meet signal strength requirements picture quality issues can occur.  After the signal is modulated it will need to be combined with the client’s cable or off air signals.  The AV training that is offered here at MMI will address this and other areas of concern in regard to whole-house video.

Basic Wiring Diagram for Modulated System

The process of modulation in the AV world is to convert one form of audio and/or video into RF (radio frequency). The types of audio to be modulated could be digital or analog (typically left and right channel information). In the video domain it could be an analog signal such as composite video, VGA or component video, although there are newer modulators that can modulate digital signals such as HDMI (used for Blu-ray DVD). Modulation is still a reliable and sometimes forgotten method to distribute AV devices throughout the home. The modulation process uses the existing cable (coax RG6 commonly found in most homes) and the television’s own built in tuner to convert the signal into picture and sound on a specified channel that is selected at the modulator. You have created your own local TV channel that plays a video source such as DVD or a Satellite Receiver that can be centrally located and shared by one or many TV’s.
So tune to channel “85” and watch a DVD. It’s easy!