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The Road to 12 Gbps 4K Video Transport

SEATTLE—With production in 4K growing steadily and the FCC’s moves to deploy the 4K-capable ATSC 3.0 standard, this year’s NAB Show will likely see a lot of 4K hardware, cameras, switchers, monitors and the like. To transport 4K video from one device to another requires a 12 Gbps path, which has sent cable and connector makers back to the drawing board.


Belden’s 4794R 12 GHz 4K UHD 75 Ohm 16 AWG Precision Video Cable Steve Lampen, multimedia technology manager at Belden, said the trick to raising the speed with which a cable can carry data is the precision in how they can make the cable. Citing the company’s new 4794R 12 GHz 4K UHD 75 Ohm 16 AWG Precision Video Cable, “Every single thing inside that cable is different, is new, is changed, is improved on, has been worked on,” he said. “The one thing we spent the most time on is the braid in the cable, believe it or not. The fact that you have bundles of wire and they all cross each other at a certain angle, and they’re a certain distance apart, this all shows up at high frequencies.”

Belden also coated the copper center conductor with silver. “That’s because the ‘skin effect’ at high frequencies is better with silver than copper,” Lampen said.

Bryan Carpenter, senior sales consultant for patchbay maker Bittree, described how the company created patchbays capable of 12 Gbps and beyond. With a rough design in hand, “we run a simulation of that design with software, and with that we can move parts and change dimensions of critical tuned areas where the signal passes.” A fraction of a millimeter can change frequency response. “With some critical dimension parts, we’ll have a 3D printing done so we can have a physical model we can push together.” When that’s done, “we do a small batch first article. This is where we have the ability to verify that the product passes way beyond 12 Gbps. We’re bringing that new patchbay out to 24 Gbps, actually.”

Frank Jachetta, president of MultiDyne, said the company has added fiber-optic cables to its fiber transport product lineup. “Being that fiber has been a wire for these higher bandwidths, it’s sort of become a necessity to do terminated cables in-house instead of farming it out to trusted subcontractors,” he said. The desire to react more quickly to customers’ fiber-optic cable needs has led MultiDyne to build “a state-of-the-art fiber lab so we will terminate the cable here; camera cable, our generic tactical cable, or any other type of optical cable that lends directly to high bandwidth.”

Mark Bradley, director of product line management at Corning Optical Communications said the company focuses on easily connecting devices that need high-speed transport. “We offer a Thunderbolt product that offers up to a 20 Gbps rate, and a USB 3.0 optical cable that provides up to a 5 Gbps rate,” he said. “What these offer is the distance capabilities of fiber with the ease and convenience of copper connectivity.”


Scott Fitzgerald, senior engineer of fiberoptic communications systems for Optical Cable Corp. said that while the company found “the 4K niche was not a product hole, per se, there were some areas where we needed to freshen our products.” OCC had enterprise customers using their 10 Gbps fiber and connectors for years, “so moving up that extra 20 percent to 12 Gbps wasn’t that big a jump forward,” he said.

One fiber connector that’s been found convenient for remote broadcasters is OCC’s Image C Multi-channel Hermaphroditic Connector, designed to enable genderless mate-ability, without regard for male or female configuration of the mating end.

“Because they’re hermaphroditic, you’ll never get to the end of a cable run and find you’ve got a socket where you need a plug,” Fitzgerald said. “Because both ends are the same, you can plug them together anyway.”

Richard Rubin, president of Tactical Fiber Systems noted that there are few 4K cameras that have SMPTE fiber connectors, and that most output via four 3 Gbps SDI cables that are then converted to hybrid fiber. “You’re seeing cameras, especially the new breed of pan/tilt/zoom cameras that have HDMI output,” he said. “And we can now provide a bidirectional RS-232 line along with the HDMI to be able to control it.” He also pointed to the 4K advantages of their Magnum stainless steel connector, which sports a female socket on the connector instead of a male plug. “There are no external parts on the cable end, which is what normally gets dropped and dragged through the mud. Running these higher bandwidths you have to be sure you’ve got a clean connector.”

Terry Dant, applications engineer and program manager at LEMO, said that in going to 4K for SMPTE 304 camera cables, “the number one change in that connector was a design for fiber optics. We switched over to single-mode optical fiber, and bandwidth limits went away. We’re not worried about 12 Gbps; they can run a tremendous amount of data over a distance of 10-20KM.”

Shadath Shahdid, engineering manager for Canare Corp. of America, said the benchmark they looked for in their new 4K L5.5 CU HD cable was 100 meters. In getting to that distance, “Canare Electric, our parent company in Japan, optimized the materials we use, in the structure and manufacturing methods.” In addition to upping the electronic performance of their new cable, the company targeted 8mm as the maximum diameter for the cable to allow more of it to be wound on a reel. The finished product came in at 7.7mm, a cable that’s more flexible and lighter.

Wendy Charak, broadcast/pro audio sales and marketing manager for Switchcraft, said in order to avoid confusion over the company’s new 24 Gbps patchbay, “we modified the color of it. It’ll be a bright panel so you’ll be able to tell the difference.”

More than just a new color scheme went into the 24 Gbps Mid-sized Video Patchbay, she said. “We redesigned the entire jack itself, and we had to have different insulators, different contact pins and other items like that. It’ll have a new looping plug and terminating plug.”

For traditional SDI connectors Neutrik created the UHD BNC connector, “which includes improvements that allow signal transmission at 12 Gbps SDI and beyond for 4K or even 8K,” said Fred Morgenstern, product director.

To those who want to continue using SDI transmission for video signals at these high rates, Neutrik has answers in place. “It is clear that IP routing is going to be integral to a great percentage of 4K applications,” he said. “The etherCON Cat6A product combines easy termination and relatively low cost with the ability to transmit 10GHz signals over up to 100 meters.”