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WEB EXTRAS - February 2010

Sun, 01/31/2010 - 7:00pm

FEATURES

Upstream Cable Echoes Come in Two Flavors 
CableLabs has established a “DOCSIS Proactive” working group with the goal of using the data in DOCSIS-based communications systems to improve plant operations. The group’s first task is to produce a recommended practices document that enables cable operators to mine the pre-distortion coefficients from the cable modem’s adaptive equalizer. That data can then be used to clean up transmission signals.

The author, Tom Williams from Arris, writes: “Cable lines typically have many small echoes, so-called micro-reflections, that will disrupt digital transmissions if not canceled. This is particularly true for highspeed upstream signals having a higher order modulation, such as 64 QAM, or having wider bandwidth, such as 6.4 MHz.

“The system chosen by DOCSIS uses pre-distortion, where a burst transmission is distorted prior to transmission and arrives at a cable modem termination system receiver with the plant’s distortion canceled. The idea is that by reading the cable modem’s pre-distortion coefficients using a network management system, technicians can tell what plant impairments a CM is compensating for, and then compute what may be wrong with the cable plant. By reading the data from many CMs, you can localize the problems using maps or connectivity data.” >>>More

DAILY NEWS & BLOGS

Maybe OTT isn’t as big of a threat as imagined. Or maybe it just isn’t yet. Senior Editor Mike Robuck takes a look at some projections that suggest there’s both less and more than imagined to the OTT challenge with “Report: Broadband TV households to top 360M by 2014” in his “Write Stuff” blog.

Visit www.CEDmagazine.com every day for news gathered and written specifically for communications service providers and their vendors, compiled by CED’s expert staff of editors. Sign up online for automatic delivery of CED’s daily Broadband Direct. And CED’s editors are now diving deeper, providing additional perspective on some of the top stories in the news. Visit our site for Editor-in-Chief Brian Santo’s blog, “And Another Thing,” and get additional insights from “Write Stuff.”

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