The New Basic Cable
Aug 23, 2011 11:54 AM, By Doug Engstrom, Technical Director, Contemporary Research
Be your own inhouse cable company.
Creating the New RF Network
For those waiting for IPTV to work, remember that digital cable is IPTV as well, and it’s been working great for years. Plus, unlike IPTV, you can retask your old RF wiring for inhouse content distribution and keep your network free for, well, networking.
In this system, origination begins a the bottom right by adding content sources, moves to the center where channels are combined, adds display control on the left if needed, then fans out to tuners and displays across the facility.
Origination: Somewhere downstairs, where the TV cable enters the building, is an area called the head end. This is where all the channels originate. In the old days, this featured the incoming cable, maybe a couple of inhouse analog channels. Today, you have many more options.
Sources: The modulators can be fed from a wide variety of sources, including:
- Cable or satellite receivers, IPTV, microwave, or other content
- Digital Signage players. If you are considering adding one or more inhouse digital signage channels, it may make sense to deliver the content over RF rather than IP. Adding new players and IP connections is expensive. If you’re delivering the same message across your facility, you can add just one or two at the RF head end and broadcast the signage over RF to displays that already have high-definition media players inside (otherwise known as HDTV tuners).
- HD-SDI video, including live event video from cameras or production switchers, and other HD-SDI and SD-SDI sources. This is a popular solution for TV stations and broadcasters such as Home Shopping Network, TLC, and others; sport facilities like the Miami Heat and Oklahoma Thunder; and houses of worship like Willow Creek Community Church.
- Digital HDTV Modulators. Arriving in a low-cost ($2,000+ per channel) form about two years ago, the HDTV modulator ingests an HD source and transforms the media into an HDTV cable channel for broadcast through the RF Network.
- Component Modulators. The most common type of HDTV modulator accepts the HD analog video from cable, satellite, and other sources. Ignore misinformation about the so-called analog sunset. The FCC ruled several years ago that component outputs on set-top boxes such as TV tuners and receivers are here to stay.
- Scaler Modulators. This specialized HDTV modulator uses an internal or external scaler to convert the VGA output of digital signage players to 1080i/720 video standards, and it can shrink the image to compensate for over-scanning on the TVs.
- HD-SDI modulators accept broadcast-quality video and convert the content to a digital cable channel.
- Analog Modulators. Despite the digital revolution, there are still good applications for analog channels. As the cost is low, about $200-$300 per channel, you can delegate some channels to analog to meet budgets. In addition, sites such as schools still have many operational analog TVs and tuners—no reason to get rid if them yet. Off-air TV is digital, but cable supports both analog and digital channels.
Combiners: Each modulator is set to a separate channel, and then the RF outputs are sent to a combiner, which does what the name implies. It combines all the separate channel feeds into a single RF output. That’s the beauty of RF over other HD distribution systems. You can run up to 135 HD and analog channels over a single wire that’s easy to install and amplify over miles. As a cable channel can carry two or more programs inside, such as ESPN HD and FOX News, an inhouse RF system can carry up to 270 full HD programs. Try that with any other network.
Amplifier: The combined master feed is then amplified to drive the RF network.
Wiring: The architecture for wiring the RF network supports a variety of wiring schemes, usually sending out core trunk feeds from the head end that then branch out at the destination to feed a group of displays and meeting room tuners.
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