Just in case full high-definition resolution isn’t enough, 4K is the next generation resolution that will deliver a whole new level of clarity at roughly four times the resolution of 1080p. Despite limited 4K content currently available to consumers, Samsung, LG, Sony, Panasonic and others are already selling 4K TV sets and widespread adoption is eventually expected. An ABI Research report from last year expects 4K to surpass 10% of North American TV households by 2018.
4K covers two formats that are both supported in the HDMI 1.4 specification – 3840p X 2160p and 4096p X 2160p. While HDMI 1.4 supports 4K resolution, adds an audio channel that enables upstream audio connections, and can deliver 100 Mbps IP-based applications with an added Ethernet channel, there are some cabling and connectivity challenges to consider that include distance limitations, installation and testing. HDBaseT resolves these issues.
Last week I was in Hollywood at the SMPTE yearly shindig. I gave my ultimate paper (so far) on 4K Video over Coax. With 500 people in the room, it occurred to me as I began that I had the perfect group to find out some things. So I began by asking my audience a question. “If I could make a single coax that would run 4K video as far as you want, how many people would put that in?” I waited for a couple of seconds. Nothing happened. No hands went up. None! An article in the TV Technology website by Deborah McAdams the next day said there were hands that were ‘tentatively’ going up, but I couldn’t see them.
I pointed out to my audience that I could save Belden a lot of money right here, and not bring out any 4K single-link coax, and save us a bundle in connectors as well. I suppose I broke a cardinal rule about public speaking, “Never ask the audience a question to which you do not already know the answer.” Well, clearly there was something I didn’t know. It was left up to me to interpret my audience’s answer. What did it mean? Read more »
I really have a problem with the word MOVIE. It sounds so juvenile. Pictures that move! Sounds like something from 1900s, back when the frame rate was really low, like 16 frames a second. No wonder they called them “flickers”.
I still occasionally hear someone say, “I’m going to the flicks.” Don’t you? I guess some things just stay with us. So, instead, we call it “motion pictures” which doesn’t sound a whole lot better. Last February at the HPA (Hollywood Post Alliance) the final speaker was an industry guru, John Watkinson (with his long hair and long beard, he LOOKS like a guru.) He got up and the first thing he said was a real epiphany. “I have never seen a movie or a motion picture.” The audience couldn’t figure out just what he was saying. “All I’ve ever seen is a series of still images, run rapidly in front of my eyes.” And because of ‘persistence of vision’ which we humans share with only a few other creatures on earth, it looks like a moving picture.
Multi-cable formats (dual and quad links) can be used today because the bandwidth on each cable is the same as HD or 3G bandwidths currently used. This is possible because recent video cards contain chips that will separate the video data into two or four signals. The signals then run over separate coax cables at a maximum speed of 3GHz (3GHz for 3G and 1.5 GHz for HD) and at the receiver, they will be transformed back to 6GHz or 12 GHz. Belden believes that its current line of cables will work to 6 GHz, but 12 GHz will require re-design and new cables.
New Cable Design
There are a number of things that can be done to improve performance of the 4K versions listed above. First is to increase Velocity of Propagation (Vp) by means of nitrogen gas injection. The limits of this technique are closely guarded secrets for most manufacturers. So can we get much higher? The problem is, as more nitrogen gas is added, dimensional stability suffers. This leads to impedance variations or “return loss”, which negatively affects performance. The solution is to reduce the size of the bubbles in the foam. Belden already offers better Vp in its well-known RF cable line with a Velocity of Propagation of 86% – 1694A has currently 82%. Unfortunately these RF cables are 50 ohm and not 75 ohm as needed in the broadcast world. So, there is still some work to be done. Thankfully Belden has both the technology and the experience, so we will be able to develop the correct cable for this new 12 GHz requirement. Improvements in shield design, such as multi-layer shielding, are also possible, although these improvements are not tied to the raw performance, such as attenuation. But shielding is certainly tied to noise immunity, which speaks to signal integrity in longer runs or noisy environments.
What About Connectors?
We see a trend towards DIN 1.0/2.3 connectors instead of BNC connectors at those high frequencies needed for “true” 4K. The outer diameter of a DIN 1.0/2.3 connector is much smaller compared to traditional BNC types. The smaller DIN 1.0/2.3 connectors (secure locking with push/pull) are less stressed than traditional BNCs, and they do not require a tight bending radius. This contributes to a better RF launch profile, and a better return loss. The smaller dimension of a DIN connector is an advantage: because of their specific design, DIN connectors for such high frequencies (up to 12 GHz) are easier to manufacture than traditional BNC connectors. Which design will ultimately take the lead? The future will tell.
If the revised distance formula, -40 dB at ½ the clock, is adopted, and if performance improvements are made, such as higher Velocity of Propagation, single-link coaxial cable for 4K formats will be able to provide the right performance for future video transmission.
One of the greatest challenges presented by the arrival of 4K video is in the ability of this signal to be carried by a single copper coaxial cable, commonly called “single link”.
Proposed Change in Distance Calculations
It is most important for a broadcaster to know how far he can transmit a signal over a single coax cable. In recent years Belden has proven that the recommended SMPTE distance calculation for HD signals can be outperformed. The original distance formula, -20 dB at ½ clock, was a reasonable “safe” value for 1990 and the technology then available. However, we believe that more than 20 years of improvements in chip design and active equipment has enabled us to surpass this calculation. Therefore, we think that a new formula, -40 dB at ½ clock, is an appropriate “safe” distance. And in the ‘real world’, Belden can go considerably further than that.
Let’s have a look at the green squares in the chart: Belden’s 1694A for example can run a minimum 113 meter with HD. With 2K signals 1694A runs a minimum of 78 meters, or 35 meters less when compared to HD. In general, all these lengths can be improved on by using our HD coaxial cables and BNC connectors. See for example the 140 meter at HD with 1694A.
If you remember that the bandwidth of 4K is 8 times HD and 4 times 2K, everyone would expect the minimum distance of a 4K signal to be less than HD or 2K. But look at the red squares. The chart clearly shows how Belden’s 1694A runs 106 meter with QuadFull-HD on a single-link! In other words: 28 meters further than 2K.
Although in my last blog I mentioned the different spec work currently underway at SMPTE, it’s time once more to take another look at 4K.
Current situation: HD is the new standard
High definition (HD) has reached European broadcast TV. It is now the new standard definition and considered to be mainstream. Having said that, at Belden we take into account that our professional broadcast customers may be managing two different HD formats.
The first of these is interlaced scanning with 720 to 1080 horizontal lines (e.g. 1080i). Each scan displays alternate lines in the image raster, and two complete scans are therefore required to display the entire image – also known as HD/1.5Gbps.
The other one is progressive scanning with 1080 horizontal lines (1080p). Each scan displays every line in the image raster sequentially from top to bottom – and is also known as HD/3Gbps. This format offers less jitter, with more stable and flicker-free video quality and sharpness. Because of the new 4K format, Belden uses the term 2K/3Gbps instead of HD/3Gbps.
Both HD formats are specified 2006 in the standards of SMPTE (the Society of Motion Picture and Television Engineers) under ST 292 for interlaced scanning and ST 424 for progressive scanning. These specifications are defined for 75 ohm coaxial cables and 75 ohm BNC connectors. By the way, ST 297 covers all SDI rates from 143Mbps to 3Gbps with optical fiber cabling infrastructure.
Most important for the broadcaster is to know how far he can transmit the signal over a single coax cable. Belden’s 1694A, for example, can have a minimum run of 113 meters with HD and 78 meters with 2K signals. These lengths can be improved when using our HD BNC connectors – for example 140 meter at HD or even further. A Gennum chip produced by Semtech can extend this to 230 meters.
One hot topic that was discussed all around the IBC was 4K. Let’s take a look at what this new technology means.
4K technology, or, to give it its official name, Ultra HD or UHD-1, is being mentioned as the next High Definition. And experts say that 2013 is the breakout year for 4K2K TVs, with a market forecast to reach 7 million sets in 2016. But will the broadcast industry really invest into a 4K workflow – and when? Though hear about a number of 4K TVs that are all direct shippable, there are still a few issues that need to be resolved – apart from the price:
Consumers will need set-top boxes that deliver the relatively rare 4K content which is currently available (most is upscaled from HD to 4K).
There are not many Live TV cameras available that are able to produce 4K – except Sony’s F55 UHD. A few, including Ikegami, have in fact skipped 4K and intend to start with 8K in a couple of years’ time.
Some countries have no way of delivering 4K, because they have already sold the available bandwidth to the cellular industry or re-allocated the frequencies to digital broadcasting.
If we look at it from a cabling perspective, 4K means that the bandwidth is growing:
Preparations are well underway for our booth at IBC 2013. I have always enjoyed being at the show, focusing on Belden’s cable and connectivity products (“the most trusted brand for Broadcast cables”).
This year, however, we have so much more to offer. Since Belden’s acquisition of Miranda Technologies, we are now also able to provide hardware and software solutions for television broadcast, cable, satellite and IPTV.
Our booth will reflect our expanded capability to deliver world-class solutions for immediate and uninterrupted transmission, flawless HD, 3G and 4K audio and video streams. We will also be introducing some new products.
To highlight just two of them, our new Duobond® Plus HD Digital Video Cables with bonded foil over the dielectric will make the termination of Belden’s 1-Piece HD BNC very easy and much faster than traditional methods with 3-Piece BNCs. It is the absolute reliable combination to deliver the needed performance!
Moreover we will be launching our extremely rugged and flexible Belden CatSnake® Tactical Heavy Duty Category 6A shielded data cables, which are designed for use in high traffic areas in a broadcast studio or for use out of doors, in broadcast truck applications, and for portable, professional audio/video use.
And if that is not enough, visitors to our booth have the opportunity to meet Steve Lampen, Belden’s Manager for Multimedia Technology and Product Line – Entertainment Products. Steve is a prolific blogger, public speaker and writer, and was named “Educator of the Year” by the Society of Broadcast Engineers in 2011.
So if you are looking for maximum reliability and performance in your broadcasts, be sure to visit our booth and see for yourself what Belden has to offer. My team and I will be delighted to see you at the show.
In June, my colleague Steve Lampen gave a number
of successful presentations in Scandinavia and the Middle East. As he explains
to Broadcast Pro Middle East, he concentrates on cable technologies for 4K, 3G
video and Ethernet AVB in his talks
The various audiences were very impressed and I would like to take this opportunity to highlight some of the latest trends in the broadcast market. Read more »