Whether we want it to or not, the industry is fast moving towards a completely digital world. From live broadcast to high quality post-production material, everything is coming out digital. To remain competitive in today's environment, both large and small businesses need to be aware of new technologies and how to best apply the technology to their individual needs. The catch is, to be able to understand how to use these new technologies to gain a competitive edge, company's first need to have a good grasp of the fundamentals of digital.

While most people have heard the terms analog and digital, few know the real difference between the two forms of transmission. I have often been told that digital is better than analog in its purest form. I find that statement strange since digital is, in reality, just a ones-and-zeros representation of analog, and as such, will never be as good as the original analog signal in its purest form. Not until an analog signal is put on copper or some other transmission medium does it begin to seriously degrade from noise (extraneous inputs such as "snow") and looses much of its quality. This is where digital transmissions begin to shine. As mentioned earlier, since digital is essentially ones and zeros, the noise associated with analog is not a factor. In addition, digital allows for compression techniques and provides a better product at the end of the cable for consumers. On the downside, digital television (DTV) is expensive, lacks current programming, and while true HDTV has phenomenal resolution, all DTV is not HDTV. DTV is also commonly used to identify both HDTV and Standard Definition Television (SDTV) which are significantly different methods used for compressing video.

In digital, a bit is a binary digit, represented by either a one (high) or zero (low). Typically in an 8-bit format, eight bits equal one byte of information; although, there are 10-, 16-, or 24-bit formats as well. The most common formats used in video are the 8-bit and 10-bit video, which provide 256 and 1,024 shades of color, respectively. Notice that a 10-bit signal not only offers a larger number of colors, but also a larger buffer for errors, i.e., a 64-value error weighs much more heavily in a 256 value or 8-bit color system. However, on the downside, the advantages of 10-bit video come with a cost to bandwidth. It simply takes more space to transmit 10 bits across the pipe than it does to transmit 8 bits. This is where compression techniques become important.

Besides eliminating noise, the other benefit of digital transmissions is the ability to use various compression techniques to help reduce the required bandwidth. Whether compressing using pixels, lines, frames, or redundant video techniques, it is possible to reduce bandwidth, and thus overall costs, without drastically reducing the quality of the video signal. An important equation to remember when discussing these compression techniques and how they are used to reduce bandwidth is "nPixels x nLines x nBits x nFrames = Data Rate in bits-per-second, or bps" which determines the bandwidth requirement. Individual or combinations of compression techniques are used in algorithms by various manufacturers to set the standards for their proprietary equipment. Since standards are not completely set at this time, many manufacturers' equipment is not compatible with equipment from their competitors. End users must be aware of these compatibility problems in order to be able to ask the vendors the right questions about equipment purchases. To quote Dr. Jolly Holden, President of the USDLA, "Now more than ever, you must define your requirements before buying equipment and services to ensure you get what you really need, not what someone else thinks you need.

Now comes the inevitable question, "How do I know what I need?" A good start is by reading current literature to become familiar with the terminology and the technology. Then identify the company's realistic requirements for the short and long term. Keep in mind that standards and technology are constantly evolving so long term requirements further out than 18 to 24 months may be unrealistic. Next, take the requirements to at least three vendors and compare costs, quality of service, and simplicity of design, among other factors. I believe this is one of the quickest ways to cut through the vendor¹s sales pitch and see the unique merits of each vendor. If possible, and time permitting, do not limit the number of proposals to three. Request as many proposals as possible. This will not only enhance the company's overall knowledge of the subject, but also improve the chances of finding the right solution for the immediate future. By applying your newly acquired knowledge of digital and the above mentioned steps for identifying and filling your digital needs, you greatly increase your chance for success in this ever changing and exciting environment.

In addition, as the technology changes, and it will, your company should be better positioned to exploit those changes. Remember that no one knows for sure where the industry is going to end up on this road to digital, but one thing is for sure, it is going to be some ride!

About the Author
John C. Rogers is Chief Engineer, Air Technology Network, Air Force Institute for Advanced Distributed Learning, Wright-Patterson AFB, Ohio. He is a Distinguished Graduate from the Strategic Air Command NCO Academy and completed his bachelors degree from Embry-Riddle Aeronautical University. His responsibilities include technical solutions for installing and maintaining over 86 downlinks and 4 satellite uplinks, which include eight broadcast studios, worldwide. As Chief Engineer, he has been the leader in providing satellite broadcast capability for the Assistant Secretary of State, Vice Chairman of the Joint Chiefs of Staff, and Air Education and Training Command Vice Commander, in addition to the regular AFIT educational programming.

John is an active member of the USDLA Advisory Board and the FGDLA . He may be reached at the Air Force Institute for Advanced Distributed Learning, Wright-Patterson AFB, Ohio