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Analog Angle Blog

Do They Know that “Analog” Makes Digital TV Possible?

Not only is today's transmitted TV signal in digital format (goodbye, analog RS-170, NTSC, PAL, and SECAM) but all the behind-the-scenes production is digital as well. That obvious fact became extremely clear as I was fortunate to get a private, behind-the-scenes tour of the CBS Broadcast Center at 524 West 57th Street in New York City, Figure 1 .

Figure 1

This aerial view of the CBS Broadcast Center, taken in 2011, does not even hint at what's inside and so allows a multifaceted worldwide broadcast operation to function efficiently and reliably. (Source: James Lin/Flickr)

This aerial view of the CBS Broadcast Center, taken in 2011, does not even hint at what's inside and so allows a multifaceted worldwide broadcast operation to function efficiently and reliably. (Source: James Lin/Flickr)

CBS purchased the site in 1952 and began using it for radio TV in 1963, and moved most of its studios, production suites, and infrastructure to the building in the following years (despite citing their Rockefeller Center (NY) office building as the official corporate headquarters) and took over more adjacent space over time. The former milk-distribution building now provides over 500,000 square feet (about 45,000 square meters) of space for studios, editing, content management, storage, and servers used for internal video handling as well as external feeds.

There were studios for the various shows, of course, editing suites for post-production work, and production centers where ten, twenty, or more people sit at control consoles and choreograph the production of live shows and events. Since several such events may be going on at the same time, there were quite a few of these set-ups.

Each had a wall of dozens of large screens, complex switching matrices handling up to 100 × 100 input/output pairings, and live links to remote events in the field. Since the actual broadcast of the many shows going out simultaneously via cable, the Internet, or over-the air broadcast TV channels is so critical, many of the set-ups are multiple redundant, and their computer-based controls, sequencers, and links can be switched over within seconds.

The procedure now used for production of remote events is to capture the images in the field, but manage all event details from this building where everyone has a place and all needed resources are ready. For example, at a major event such as a football game, the cameraperson in the field is linked by audio and video back to the production team in this building, and is directed what to do and when by them. If an instant replay is needed, that is implemented by the studio personnel, not the field. This remote management is possible only because of the extensive, multiple, links (spanning thousands of miles, if needed), using fiber and backup satellite between field and studio.

While we did swing through the various studios where shows are either broadcast live or recorded for later use, the highlight for me was going into the guts of this enormous building floor by floor, from the third-level sub-basement almost to the roof (sorry, no photos permitted). While this is a legacy facility, the equipment has been repeatedly upgraded, and nearly all the massive coaxial-cable runs have been replaced by fiber-optic cables.

Beyond these up-to-date, non-glamorous but highly functional studios are the racks of servers and fiber links, with room of racks, servers, and cabling. Unlike the “rat's nest” of scrambled, spaghetti-like cabling you may see in “what's wrong with this?” photos, every bundle of the cables here was beautifully tied and labeled, and every termination panel, display, or interface was also meticulously labeled; I did not see a single hand-scrawled tag or label anywhere.

Looking at all this “digital” production and digitized video, and one point hit me hard: it's all due to analog. Every one of those fiber-optic cables starts with an LED driver and LED, and ends with a photodiode and transimpedance amplifier, along with other analog circuitry and power sources. Similarly, every one of these live audio/video links between studio and the field needs A/D and D/A converters, line drivers ad receivers, and more. The digital cameras also need analog circuitry for interfacing with their CCD/CMOS imagers as well as driving the link digital video to the studio. Even the largest studio, with over 300 computer-controlled lights hanging from the ceiling, needs power controls in the form of MOSFETs, TRIACs, and IGBTs, as do the remote-controlled robot-arm cameras which have largely replaced the handheld or dolly camera in the studio.

Despite all this, the only visible indication of “analog” I saw was the occasional old-fashioned clock with hands nestled among countless, digital clocks; whether this was done for legibility, convenience, or as a reminder of the past, I don’t know.

At end, I was extremely impressed and even somewhat shocked at how digital has totally taken over all aspects of video capture, production, and broadcast. This was made even clearer when we passed a special room with legacy 2- and 4-inch tape drives, videotape cartridge players, and video digitizers, for when an old video clip is needed; any videos recorded in the past decade and further back is already digital and can be called up instantly with a few keyboard clicks.

At the same time, I wonder if the folks operating all this “digital video” realize that much of its viability is due to low-cost, low-power, high-performance analog ICs and functional blocks which allow the digital world to function. I suspect not, and if you mention that it is analog which makes this digital regime possible, I suspect they will think you are either trapped in the past or seeking to swim along and get some of this leading-edge glory.

But we know better, right? Have you ever tried to make the case that this digitized world is largely due to the availability of suitable analog components? Were you successful at this?

References

  1. getting-to-know-the-broadcast-center
  2. CBS_Broadcast_Center
  3. A tour of the CBS broadcast center (YouTube video)
  4. a-tour-of-the-cbs-broadcast-center (video)

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4 comments on “Do They Know that “Analog” Makes Digital TV Possible?

  1. Bill_Jaffa
    December 27, 2016

    For a photo of stunningly nice cabling similar to what I saw at CBS, as well as the worst two you'll ever see (most likely), check out this page from the always interesting “Cabling Installation & Maintenance” publication–always has good “real world” insight:

    http://www.cablinginstall.com/articles/print/volume-24/issue-12/departments/infrastructure-insights/cabling-exceptionalism-order-vs-chaos.html

    (The online photos have much more resolution that the fairly small ones that ran in print)

  2. antedeluvian
    December 27, 2016

    Bill

    Thanks for your link to good and bad cabling examples (link added for others' convenience). I did not know there was a publication dedicated to the subject!

    I thought I might point out that I did a blog “Tidy Your Wiring” on the same subject.

  3. David Ashton
    December 28, 2016

    Thanks for that Bill, interesting stuff.  To stay on the subject of cabling, I had in the past to do a fair bit of this at work and it drove me scatty.  At one stage I rewired all our patch panels and ethernet switches so that the switches were directly above the patch panels they were feeding.  I connected switch ports directly to patch panels hence saving a lot of space in our previously way overcrowded cable management trunking.  I had cables custom produced in three different lengths (I think 150, 200 and 250 mm – 6/8/10 ins) to make for an extra-neat job.  It looked beautiful when it was finished, but over the years entropy has crept in.  Rather than wire a new cable to a different port for a special purpose connection (say a SCADA connection instead of the usual corporate LAN) someone would wire in a new cable and disrupt my nice layout.  Or when wiring a connection to the core switch, they'd wire a 3m cable at a crazy angle to reach, instead of getting a 5m cable to do the job properly.  Or (the most heinous crime) the patch panels to the server racks were those v-shaped ones where patch outlets 1-12 are cabled from the left, 13-24 from the right.  To save getting a longer cable someone would cable across the middle.  Eventually I put on a label down the middle “Police line, DO NOT CROSS” and told everyone that if any cable did cross it, it would be removed and I didn't care if a server went down. I only had to do that once!  Fortunately the server was pre-production, otherwise I could have landed myself in hot water…..  It's usually IT guys who are the guilty ones, I've offered to cable anything for anyone anytime, but some of them will still do it themselves.  Grrrr…

    And nice blog @Antedeluvian, I'd missed it previously.  A man after my own heart….

  4. vbiancomano
    December 30, 2016

    Well done. I am puzzled, however, why anyone would find a need or want to make the case that today's digitized world is largely due to the availability of suitable analog components, even if it is so. The exercise is a bit of a takeoff on comparing athletes (or just about anything) of different eras. For the most part it's not doable, for each has its own unique coordinates in time-space. And often the rules of the game have changed, or latter events are often dependent on former events to complicate the discussion. Or the “judges” have different yardsticks for measuring. For example, who was the greater quarterback, Unitas or Manning/Brady? Who was a greater theoretical physicist, Maxwell or Einstein?

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