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Archives
 June 1999 Issue
Hranac - Notes for the Technologist
Everything You Always Wanted To Know About Cable, but Were Afraid to Ask
By Ron Hranac
Every now and then, a good book comes along that is a must-have. This month, I review two such publications, both of which should be sitting on yourbookshelf if they arent already there.
The first is an engineering reference book specifically about cable TV technology, and the second, while targeted to the amateur radio community, contains a lot of information that will be helpful to those sorting their way through RF interference problems, cable or otherwise.
If you could pick only one &.
Modern Cable Television Technology: Video, Voice, and Data Communications; Walter Ciciora, James Farmer and David Large; Morgan Kaufman Publishers, Inc.; 1999.
Over the years, a number of very good books on cable TV technology and related topics have been written. But none approaches the reference quality of Modern Cable Television Technology, a nearly 900-page hardcover tome by three of our industrys most respected engineers. Indeed, The Strategis Groups Archer Taylor said in the first sentence of the books foreword, "Modern Cable Television Technology seems destined to become the standard engineering reference work in the rapidly developing field of cable television." Im inclined to agree.
Ill admit up front that I havent sat down and read the book from cover to cover, but I have had a chance to skim its contents during the past few months, and Ive used it as a job-related reference on several occasions. I also randomly picked a few topics to read in depth, intentionally looking for gotchas. I found a few that made it past the editors ("the breath of his experience," Ron Cottens name misspelled and similar such) and a very minor technical point or two that made it past the peer review process. For instance, -59.17 dBmV for room temperature 75 ohm thermal noise: The math actually works out to -59.1590976 dBmV. But whats a hundredth or so of a dB? Seriously, my only real complaint, if it could be called that, is not about the books quality, but its quantity. Its not big enough.
Nine hundred pages isnt long enough?
Modern Cable Television Technology easily could have been several hundred pages longer. I had a chance to speak with co-author Jim Farmer about this, and he chuckled while explaining that the publishers original size limit was around 600 pages. This number was increased twice while the book was being written. Jim noted there was more than one spirited discussion about what and how much to include.
In lieu of what ultimately might have been a 2,000-page book, the end of each chapter directs the reader to several references that will provide more in-depth information on related subjects.
The sum of the parts
That said, lets look at what is included. The books content is divided into six major parts: Part 1"Once Over Lightly;" Part 2"The Signals;" Part 3"Headends;" Part 4"Broadband Distribution Systems;" Part 5"System Architecture;" and Part 6"Customer Interface Issues." All except Part 1 consist of several chapters each.
"Once Over Lightly" provides an introduction to cable TV, including a brief look at its history, how a cable system works and some comments about cables economics. This part is a nice overview for folks just starting out in cable, or those who may be less technically inclined. Its also suitable for those with an engineering background, but in a different field.
"The Signals" covers in four chapters analog TV, digital compression, data transport (including an overview of the Data Over Cable Service Interface Specification, or DOCSIS) and cable telephony.
Part 3 does a nice job with headends. Here the reader will find a good description of antenna fundamentals, satellite reception, signal processors and modulators, TV stereo, channelization, and signal quality measurements.
"Broadband Distribution Systems" takes care of the outside plant. Besides discussing the coaxial network and its design, Part 4 includes fiber optics as well as useful information about amplitude modulated link (AML) microwave and microwave path engineering principles. Unfortunately, little is said about long haul frequency modulated link (FML) microwave. This part also devotes a chapter to the reverse path.
"System Architecture" introduces the reader to performance considerations as they relate to network architecture and gives several examples of different architectures that have been deployed in cable systems. I was pleased to see the authors included a chapter on network reliability and availability, along with references to CableLabs 1992 Outage Reduction.
"Customer Interface Issues" discusses conditional access (CA), which the authors call "program denial technologies," the ever-changing consumer electronics interface, and equipment compatibility.
The book concludes with a much-too-small appendixit has a TV channel allocation chart based on EIA/ANSI-542 and some background on the NTSC video waveformand a helpful glossary.
Primary value
Modern Cable Television Technology will appeal to a fairly broad audience. The subject matter intentionally covers much of the material included in the Society of Cable Telecommunications Engineers certification programs and, as such, will be a good resource for exam preparation.
For those in search of a truly comprehensive cable engineering reference volume, you simply wont find anything better. The overall writing style will appeal to most readers and is a reflection of the three co-authors excellent communication skills. If youve ever heard any of them speak at engineering conferences, youll know what I mean. The book does contain a fair amount of math in places, offering a rigorous analysis of several topics.
I have no hesitation about recommending this book to anyone employed in the technical side of our business, or to persons with an interest in cable TV engineering. Ciciora, Farmer and Large have a real winner on their hands and are to be commended for taking the time to collaborate on this excellent publication. Modern Cable Television Technology is available through bookstores, or even better, from SCTE: 140 Phillips Road, Exton, PA 19341; ; fax ; or on the Internet at www.scte.org. If you buy it from SCTE, the cost is $96 for non-members and $80 for members.
Figure out RFI
The ARRL RFI Book, First Edition, The American Radio Relay League, Newington, Conn., 1998.
The second book to add to your reference library is The ARRL RFI Book. As I mentioned earlier, this publication is geared toward the radio amateur, providing a comprehensive background on the subject of radio frequency interference (RFI). Despite being called a first edition, this actually is a completely rewritten version of earlier ARRL publications covering the same subject matter.
What makes this softcover book of interest to cable personnel is its thorough overview of RFI. Understanding many of the sources of interference discussed in The ARRL RFI Book will prove helpful in tracking down signal leakage and ingress problems, particularly from the perspective of where and how some of the over-the-air interference occurs. There are a variety of troubleshooting tips and fixes for specific interference problems, including common-mode currents on the outer surface of cable shielding.
Chapter 7 covers cable TV interference, and while intended primarily for the benefit of the ham operator who experiences cable TV signal leakage-related interference, it discusses the responsibilities of both parties when problems occur. This chapter has been appended with a reprint of a three-part article that appeared previously in Communications Technology.
The ARRL RFI Book can be ordered at most bookstores, purchased at most ham radio stores, or is available directly from the ARRL: 225 Main St., Newington, CT 06111; ; or on the Internet at www.arrl.org. The cost is $20. - CT
Ron Hranac is vice president of RF engineering for High Speed Access Corp. in Denver. He also is senior technical editor for "Communications Technology" and can be reached via e-mail at .
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