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.

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January 31, 2000 - Issue 199Final Edition

DTV - Sinclair Calls Zenith CES 8-VSB Demonstration "Misleading and Possibly Flawed" (Jan. 31)
Sinclair Broadcast Group, Inc. criticized Zenith Corporation's demonstrations at the Consumer Electronics Show in Las Vegas and in Washington D.C. comparing the performance of ATSC 8-VSB and DVB-T COFDM terrestria DTV receivers (RF Current January 17) Sinclair said that "The use of simulated, rather than live, multi-path test signals did not allow for full evaluation of the two systems, as had been previously found by Motorola." ( RF Current January 03).

Sinclair engineers said that "a potentially major flaw in the demonstration was the use of signals levels sent into the COFDM receivers that may have exceeded their operational design limits." Specifically, Sinclair said Zenith said the input level to the 8-VSB receivers was set at -30 dBm. According to Sinclair, the maximum input specification for at least one of the COFDM receivers used in the demonstration was -30 dBm and the second demonstration receive had a -35 dBm specification. The RF signal level was increased above -30 dBm to compensate for the 8 MHz bandwidth of the COFDM receivers, outside the maximum input specification for the receivers. This overload was exacerbated when multi-path and noise simulation signals were added.

A senior Sinclair engineer, Mark Aitken, commented, "This demonstration would have been much fairer if there was no possibility of distorting the results by overdriving the test COFDM receivers." Copies of Sinclair Broadcast Group news releases may be found on Yahoo at http://biz.yahoo.com/n/s/sbgi.html. Also see the Sinclair Broadcast Group DTV web site.

DTV - Granite Broadcasting Corporation Gears Up to Broadcast Web Content over TV (Jan. 31)
Granite Broadcasting Corporation has begun trials to broadcast of Internet content over its KNTV and KBWB DTV stations in the San Francisco Bay area. Granite will use Harris Corporation's Dataplus(tm) product, which includes Skystream Networks' media routers. The Press Release posted in Adobe Acrobat format on the ATSC web site did not mention the consumer receiver hardware to be used in the broadcasts.

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