RF CURRENT



Welcome to RF Current, a weekly electronic newsletter focusing on Broadcast technical and F.C.C. related issues. This newsletter is part of The RF Page @ www.transmitter.com, a web site devoted to TV Broadcast RF engineering. For more information see the What is... guide to the R.F. Page site.

Issues are dated each Monday, although recently I've needed an extra day or two to complete each issue. Articles may be posted earlier if time permits or if there is a major, breaking story.

NOTICE: RF Current is no longer listing routine FCC DTV applications or actions for individual stations. As a substitute for these listings, I'm now posting an Excel spreadsheet containing all DTV service entries in the FCC Engineering Database in Microsoft Excel 3.0 format. This file should be able to be read by all current spreadsheet programs. Please let me know if you have any problems with it. Using the "Auto-Filter" feature in later versions of Excel, it is possible to search by state, channel number or even ranges of transmitter location coordinates. Download compressed (Zip) file fccdtvdb.zip. This file will be updated weekly. Check the date of the database on the The RF Page @ www.transmitter.com home page. Petitions for rule making to change DTV channel allocations will continue to be listed here.

<<< Back to December 6 - Issue 193

December 13, 1999 - Issue 194 Final Edition

CHIPS - Oren Semiconductor's Announces Programmable Demodulator Chip for DTV (Dec. 13)
Oren Semiconductor announced an 8-VSB demodulator chip with a built-in DSP programmable with a serial or parallel interface. The DSP can reconfigure "on-the-fly" all parameters of the 8-VSB demodulator, the matched filter, the adaptive equalizer, forward error correction, the numerically controlled oscillator, and the phase locked loop. The chip's ability to reconfigure the adaptive equalizer to optimize recovery of the main signal improves indoor reception of 8-VSB signals. The chip, the OR51210, has full adaptive equalizer with 576 taps, typically configured for a -4.5 to +44.6 microsecond echo delay range.

In addition to reconfiguring the adaptive equalizer for the reception environment, the DSP can also program the demodulator and matched filter to match the noise characteristics of the attached tuner and compensate for frequency distortions. It can also change response to improve rejection of adjacent channel NTSC signals. One feature present in this chip that was not present in some of the earlier 8-VSB demodulator chips is the ability to report FEC statistics, receiver lock status and channel parameters, including S/N ratio. equalizer tap values, and carrier and antenna positioning information.

The chip is available now in sample quantities. Production is scheduled for 1Q 2000. The price will be $24 for the 100-pin plastic quad flat package in quantities of 1,000. More information on the chip and a block diagram are available on the Oren OR51210 web page. The page also contains a link to a Product Brief PDF file. It may not current, however, as it is dated September 1999. (Information from BusinessWire)

DTV - Sinclair Appeals for Broadcaster Support of COFDM Proposal (Dec. 13)
In an email to broadcasters, Nat Ostroff, Vice President of New Technology for the Sinclair Broadcast Group, said "The apparent sales strategy of the consumer industry is to focus on DVD and satellite sales and ignore over-the-air." Ostroff wondered if the consumer electronics manufacturers might "fear the consumer will hesitate to buy such hardware if they became aware that the 'good old local broadcast signal' is not going to be easily available. Furthermore, they may have second thoughts if the consumer knew that the receiver box they just bought might not work for all stations." He asked, "Does CEA want to avoid this loss of business scenario, even if it means permanently handicapping the nation's over the air industry?" Ostroff's opinion is that the answer is "Yes", stating, "They have written off over-the-air delivery as being an unimportant component of their sales pitch. Thus they do not want to invest another cent in improving something that is not necessary to their perceived success."

Ostroff warned, "All broadcasters who value their businesses and want to participate fully in the DTV future, as well as members of the viewing public who want to preserve free television, need to make it clear to the FCC that they and eventually the American public, expect the FCC to do its job and meet the responsibility that clearly falls to their offices. Ask, no demand, that the FCC do its job and open the debate on the performance of over-the-air DTV using the current 8VSB modulation standard."

More information on Sinclair's efforts to open the U.S. DTV standard to COFDM (used in the DVB-T standard) as well as 8-VSB is available on at www.sbgi.net/dtv.

DTV - Thomson Says NYC Demonstrations Highlight Strength of Current DTV System (Dec. 10)
PRNewswire carried a press release from Thomson-Multimedia, New York City Demonstrations Highlight Strength of Nation's New Over-the-Air Digital TV Broadcast System that took issue with the argument that 8-VSB does not work well with indoor antennas. The demonstration, conducted by Thomson, the manufacturer and marketer of RCA digital TV products, showed an 8-VSB DTV signal transmitted from the Empire State Building could easily be received using a simple $6.95 set-top antenna on the first floor of a midtown Manhattan townhouse. The demonstrations were conducted with a new wide-screen 38-inch RCA HDTV and the $649 (list) RCA DTC100 set-top box. During the demonstration with the indoor antenna, VHF analog TV broadcasts could not be received. It was possible to receive a "fuzzy, ghosting" analog UHF signal. However, Thomson says, it was easy to receive the digital broadcast from the Empire State Building.

Thomson Senior Vice President Mike O'Hara was confident 8-VSB was the right choice for broadcast transmisisons. He said, "Even in the largest city in America, in a high multi-path environment, on the first floor, surrounded by skyscrapers, using an off-the-shelf antenna purchased yesterday - digital TV works like a charm. The Vestigial Side Band (VSB) modulation method for digital TV is the right solution for broadcasters. VSB will perform exactly as designed, provided that the digital receivers are well-designed and sensitive to over-the-air transmissions. I think you have to question the motives of some in the broadcast industry who may be trying to delay the digital TV transition for their own special interests"

The station received during the demonstration was not identified, but the language used appears to indicate only one of the two stations transmitting DTV was used. Both WCBS-DT channel 56 and WNYW-DT channel 44 broadcast DTV from the Empire State Building. According to Thomson, over forty electronics industry reporters were present for the demonstration, so more technical details may be available once their articles are published.

FCC Notice of Proposed Rule Making to Modify DTV Table of Allotments in Evansville, Indiana (Dec. 8)
Tri-State Public Teleplex, Inc. (Tri-State), licensee of noncommercial station WNIN, NTSC Channel 9 in Evansville, Indiana, has requested the substitution of DTV Channel 12 for its assigned DTV Channel 54. Tri-State states the channel change will allow it to preserve its limited resources, citing additional power costs of up to $250,000 per year to operate a 1000 kW DTV station on channel 54. In addition, because channel 54 is outside the core spectrum, it would be reclaimed by the Commission for other purposes and the station would be required to move to another channel after the transition period.

The FCC has found this channel change would meet its requirements. The technical parameters of the modified allotment on Channel 12 would specify an effective radiated power of 15 kW at a height above average terrain of 177 meters.

Interested parties may file comments on or before January 31, 2000. Reply comments are due on or before February 15, 2000. Refer to the Notice of Proposed Rule Making (MM Docket 99-346) for details on the request and information on filing comments.

DTV - ATSC Releases Standard A70 - Conditional Access System for Terrestrial Broadcast (Dec. 7)
The ATSC has released ATSC Standard A/70, defining the Conditional Access System for ATSC Terrestrial Broadcasting. The standard does not presume a business model, but instead defines the building blocks necessary to achieve interoperability between conditional access (CA) modules and hosts designed to support ATSC CA. The module is replaceable, to protect it against obsolescence. The document cautions "This document describes an architecture that shall be applicable to terrestrial (over-the-air) broadcast systems. Applicability of this document to cable and satellite broadcast systems is outside the scope of this document."

The document contains a large amount of well written informative material that is useful as a tutorial on conditional access techniques. It may be downloaded from the ATSC web site as an Adobe Acrobat file A_70.pdf.

FCC Sets December 31, 1999 Deadline for Letters of Intent to Maximize DTV Facilities (Dec. 7)
The FCC released Public Notice DA 99-2739 alerting broadcasters that under the Community Broadcasters Protection Act of 1999 (Act), signed into law November 29, 1999, low power TV (LPTV) stations that qualify for a Class A license are protected from interference until the final resolution of their Class A license applications. Service areas of Class A designated stations are not, however, preserved with respect to DTV stations seeking to replicate their analog service area nor from "maximized" DTV facilities for which applications or notices of intent to maximize were filed by December 31, 1999.

The FCC defines "maximization" as DTV station operations with an effective radiated power and/or antenna height above average terrain which exceed that initially granted in the FCC's DTV Table of Allotments. Notices of intent to file a DTV maximization application must be filed by December 31, 1999. Actual technical facilities to be proposed need not be stated. For more details, refer to Public Notice DA 99-2739.

OTHER Items of Interest

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Last modified December 14, 1999 by Doug Lung dlung@transmitter.com
Copyright 1999 H. Douglas Lung