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.
This page contains stories from RF Current issues published in April 1997. Links referenced in the articles were current when published but by this time may have changed. If you find a bad link, try connecting to the home page of the publication or company and look for an archive of past articles. If you find a changed link, I'd appreciate it if you'd let me know by dropping me a note indicating the new location at dlung@transmitter.com.
Harris Corporation, in a Response issued today, said it "will seek to set aside a Federal District Court jury decision regarding alleged patent infringement of a circuit, which was used in one model of the company's earlier analog UHF television transmitters." Harris noted that the technology is no longer used in Harris' analog transmitters and has never been a part of Harris' digital transmitter line. Harris has its own U.S. patent, issued in 1995, for its corrector. The corrector is used to reduce interference between the visual and aural carriers in common amplification transmitters.
Richard Ballantyne, Harris vice president and general counsel said "We plan to aggressively seek to have the jury decision set aside and, if necessary, appeal the ruling to the Federal Circuit Court of Appeals."
The FCC today released its monthly list of experimental authorizations. It is useful as in indicator of new RF technology being tested and it also serves to alert other users of the spectrum to potential interference.
Interesting technology this month includes a grant to the University of Michigan for a license to use 2130 - 31960 kHz. for an "Office of Naval Research contract to measure ocean and atmospheric parameters." Intrinzix Technologies was granted several licenses in large cities around the U.S. for testing of IVDS in the 218-219 MHz. band. Digital Wireless Corporation will use UHF TV channel 21 to test a digital trunked radio system in the San Fernando Valley in Southern California. TV Broadcasters and common carriers will be interested to know that Robinson Helicopter Co. was granted a license "to operate in 1990-2110, 2450-2483.5, 6425-6525, and 6875-7125 MHz. for demonstrations to potential customers and for FAA certification." The area was listed as continental United States, Alaska and Hawaii. M/A-Com, Inc. was granted an experimental license for frequencies in the 30 GHz. range for propagation studies and to test and develop LMDS equipment.
The complete list is available on the FCC web site.
In a Press Release issued today, COMARK Communications, Inc. said "a Federal jury in Philadelphia found the Harris Corporation's Broadcast Division willfully infringed on a COMARK Communications, Inc. Aural Carrier Corrector patent for a period of 3-1/2 years." The jury awarded COMARK 7.7 million dollars based on its findings. Additional damages may be awarded to COMARK for the "knowing and intentional" infringement of COMARK's intellectual property.
Earlier this week the FCC issued a News Report saying:
FCC Chairman Reed E. Hundt and Mexico Undersecretary of Communications and Technological Development Javier Lozano Alarcon of the Secretariat of Communications and Transportation (SCT) have signed a Memorandum of Understanding (MOU) that will facilitate the introduction of digital television service (DTV) along the USA/Mexico border. This MOU, titled Memorandum of Understanding Between the Federal Communications Commission of the United States of America and the Secretaria de Comunicaciones y Transportes of the United Mexican States Related to the Use of the 54-72 MHZ, 76-88 MHZ, 174-216 MHZ and 470-806 MHZ Bands for the Digital Television Broadcasting Service Along the Common Border, establishes interim principles to be applied in the allocation of frequencies for use by DTV operations.
The FCC has set up a Web Page that contains links to the full text of the Memorandum of Understanding and related information. It was not clear whether or not this agreement will result in changes to the recently released DTV Table of Allotments in the FCC's 6th Report and Order. Any changes near the border could ripple throughout southern California and Arizona, and have an impact on the many border towns in Texas.
Compaq Press Release on PC Theatre Deal with Thomson Consumer (RCA) (Apr. 28)
EE Times Article on PC Theatre (Technical Details) (Apr. 28)
Acrodyne Press Release on Single Tube 25 kW (average) DTV Transmitter (Apr. 23)
FCC Announcment of Open Forum on Electronic Filing Proposal at FCC on April 30th (Apr. 25) (See this release for details on a live audio feed on the Internet.)
Today the FCC's Fifth Report and Order,which covered the rules for the DTV transition, became available on the Internet. Like the Sixth Report and Order released yesterday, the Order, for now, is only available in WordPerfect or Adobe Acrobat PDF formats. Appendix D is not included in the WordPerfect version. If you need it, it is available as a separate PDF file.
Key items worth noting in the 5th R&O. Stations have only 90 days to notify the FCC if they do not want their DTV channel. The Order did not state what would happen to stations who did not opt out of the second channel and didn't construct it. It also didn't specifically state that stations that decided not to go for the second channel would be able to switch to digital on their existing analog channel in 2006 when analog TV broadcasting is scheduled to end. Being an optimist, I took this to mean stations that didn't go for a second channel could convert on their existing channel, if it was in the core spectrum. There are a lot of unanswered questions here. Obviously, it wouldn't be a good idea to return that DTV license until these issues are clarified.
The FCC will issue an Initial Modification License For DTV to each of the stations listed in Appendix E of the 5th Report and Order. This isn't a construction permit, but accepting it is conditioned on the station surrendering either the additional license or the original license to FCC "for reallocation or reassignment (or both) pursuant to Commission regulation." Stations accepting these licenses must file for a construction permit (the form is in the 5th R&O PDF package) "before the mid-point in a particular applicant's required construction period has expired." The application is quite streamlined compared to the previous analog NTSC CP application. Construction periods expire May 1, 1999 for all network (ABC. CBS, Fox, NBC) affiliated stations in the top ten TV markets, November 1, 1999 for all network-affiliated stations in the top 30 TV markets, May 1, 2002 for all remaining commercial TV stations and May 1, 2003 for all noncommercial TV stations.
Stations will be considered in compliance with these deadlines even if they choose to start broadcasting at a power less than that authorized in the 6th R&O DTV Table, provided they provide coverage over their entire principal community. Coverage is defined as a 28 dBu field strength for low VHF channels (2-6) , 36 dBu for high VHF channels (7-13) and 41 dBu for UHF channels (14-69). Field strength for this purpose is defined using an FCC 50/90 curve (50 percent of the locations 90 percent of the time) derived from the existing FCC 50/50 and 50/10 propagation curves. The FCC method for deriving FCC 50/90 coverage involves subtracting the difference between the FCC 50/10 and FCC 50/50 coverage distance from the 50/50 coverage distance. The 6th R&O said that applications for power increases from stations operated at less than 1,000 kW average ERP will be entertained provided they do not cause interference and do not exceed the Grade B contour of the largest NTSC station in the market.
Limits on out of band emissions have been changed. The earlier number was referenced to the average power in a 500 KHz. portion of the channel. The new requirement of -46 dB is referenced to the average power across the entire 6 MHz. channel.
Interference calculations will be based on Version 1.22 of the Longley-Rice Irregular Terrain Model for propagation. Details on how this model is to be applied and the necessary parameters to use will be in OET Bulletin 69. Stations desiring to co-locate with other broadcasters will be able to do so as long as the move does not create any new interference. Coordinating committees may be formed to change the channel assignments in a market (providing no interference results to stations not included in the changes). Input from the public and participation by LPTV and Translator stations in the area must be considered in these coordinating committees.
Finally, there will be a simulcast requirement. Fifty percent simulcast of the video programming on the analog channel will be required in sixth year from the date of adoption of the 5th R&O. This increases to 75 percent by the seventh year and 100 percent by the eighth year, until the analog channel is terminated and spectrum returned.The FCC late today released its much anticipated Sixth Report and Order on Advanced Television Systems. As of today, the Report and Order was only available in WordPerfect and PDF (Adobe Acrobat) formats. The Appendix containing the actual DTV Table of Allotments and details on the technical parameters used to create it were released separately in WordPerfect and PDF formats. A simple, HTML, state by state listing exacted from the FCC 97-115A is available here at http://www.transmitter.com/FCC97115/chanplan.html. The FCC's Office of Engineering and Technology has set up a web page with links to these documents.
A quick glance at the new DTV Allotment Table and the Sixth NPRM showed that UHF stations saw a 3 dB drop in transmitter power. 40.8 dBu is now considered an adequate signal, based on a 7 dB UHF receiver noise figure. VHF stations moving to UHF, the ones that originally received digital powers as high as 5,000 kW average power were capped at 1,000 kW maximum ERP, average. The FCC didn't truncate the ERP when the power needed to replicate coverage exceeded 1,000 kW. Instead, it scaled the entire antenna pattern so that the maximum average ERP did not exceed 1,000 kW. VHF stations using directional antennas should pay particular attention to this.
UHF broadcasters are not likely to be satisfied with this table. Many saw their powers halved by the reduction in receiver noise figure to 7 dB from 10 dB. Although VHF stations moving to UHF were capped at a more reasonable power level, UHF signal disparities up to 13 dB will still be present in many areas. Given the threshold or cliff-edge effect of DTV, a viewer who wants to receive UHF stations staying on UHF DTV channels will need an antenna system with up to 20 times more gain than that needed to receive VHF stations moving to UHF DTV channels. Otherwise, the lower power UHF stations won't even appear on the TV.
Researchers at Oak Ridge National Laboratories have developed a "half living, half silicon chip to detect pollutants, explosives and a number of chemicals in soil and water." They've nicknamed the devices "Critters on a Chip". The proper name is "bioluminescent bioreporter integrated circuit. " The device uses a genetically engineered microorganism that produces light as it breaks down hazardous waste. The Critter Chips are expected to be cheap to produce and could form the basis for a series of chips with living organisms in them for other environmental monitoring. Full details are in the press release from ORNL.
Andrew Corporation Offers DTV Trade Up Credits on Interim DTV Antennas (Apr. 7)
PBS Selects GE Americom For National Satellite Distribution (Apr. 15)
Engineers Develop Technique to Build Computer Chips One Atom at a Time (Apr. 18)
Broadcasters at the NAB Convention in Las Vegas scrambled for details on how the FCC's new DTV Table of Allotments would affect their stations. Rumours about the new DTV Allotment Table were contradictory -- during Sunday's engineering session one presenter said the new Table had fewer adjacent channel allocations. Later, I was told by another person that someone close to the process told him there were more adjacent channel allocations. Today I heard there were over 1,000 changes in the new Table. Given that there are approximately 1,600 TV eligible for DTV channels, this would be significant!
During his Thursday morning presentation on the DTV Allotments , Richard Smith from the FCC said the Table would be released "in a week or ten days." Much of his presentation echoed the news releases issued last week. See the April 7th Issue, below. However, he did take the time to expand on some items and answer questions.
Temporary DTV facilities would be allowed within a 3 mile radius of the station's NTSC transmitter site. Questioned about co-location of "suburban" TV allocations, such as channels 18, 30, 56 and 62 around Los Angeles, he said this would be permitted, but did not go into details. (I suspect it will have to be resolved with the local channel coordinating committees allowed in the Report and Order.)
When questioned on the close proximity of some DTV stations to Land Mobile stations in the 6th NPRM's Allotment Table, Mr. Smith replied that Land Moble stations would be protected, however, some Public Safety licenses on TV frequencies granted under a waiver of the rules may have to move. Dr. Byron St. Clair, representing the National Translator Association, stated it was unfair to remove channels 60 to 69 for translators, noting that many translators depend on links in this band to deliver TV to rural communities. Richard Smith, commenting on the plans for channels 60 through 69, said that 24 MHz. were targeted for Public Safety use. The rest were open, perhaps for broadcast, probably distributed by auction.
Overall, Smith said the Allotment Table required a lot of compromises but stated that "this is the best we can get over-all."
LPTV and translator broadcasters feared the worst and hoped for the best as they waited the release of the new Table. During "The Switch to DTV" session Wednesday morning, FCC Commissioner Reed Hundt's assistant, Saul Shapiro, said that there was a conflict between the DTV transition and LPTV. However, he remarked "Not all is lost," and added that 60 percent of LPTV stations are not affected and 80 percent of translator stations are not affected by the new table. He did indicate some stations may need to move.
Comments from Commission staff generally seemed supportive of LPTV and translator stations. FCC Commissioner Ness noted that "Low power offers a valuable service" and said "I want to enable as many LPTV stations as possible to prosper in the digital age." These comments were in her April 3rd statement released when the FCC's DTV Report and Order was announced.
The Order includes several measures that will benefit LPTV. LPTV stations will be allowed to file non-competitive displacement applications when applications are filed for DTV stations that would interfere with or displace them. LPTV stations will be allowed a great deal of flexibility in responding to the displacement. Word was they will be able to change location, perhaps co-locating with the DTV station to maintain interference ratios, and will be allowed, to the extent interference criteria allow, to increase power -- up to 3,000 watts ERP on VHF channels and up to 150,000 watts ERP on UHF channels. Power limits will be based on ERP, not transmitter output power. Some channel taboos have been removed. Interference protection will be based on the more realistic Longley-Rice propagation model instead of the often over-optimistic FCC coverage charts. Commissioner Ness, in her April 3rd statement, said "I expect that the adoption and release of our specific allotment table will enable engineers to go to work -- as I know the Community Broadcasters Association has suggested -- and find channels where existing low power stations can be accommodated." The CBA, in conjunction with the Translator Association, deserves much, if not all, the credit for getting these provisions into the DTV rules.
INTELSAT today released the results from its third round of digital video interoperability testing. These tests were more strict than the earlier ones and were designed to test "plug and play" operation in both NTSC and PAL standards. Ten digital video compression system manufacturers participated in the tests: California Microwave/STS; Divicom; DMV; Magnitude Compression Systems, Inc./General Instruments; Scientific-Atlanta, Inc.' Tadiran Scopus DVC; Tandberg Television AS; Thomson Broadcast Systems; Tiernan Communications, Inc.; and Wegener Communications.
INTELSAT did not post results of the tests on its web site. A press release tells how to get copies of the results. A report summary is available.
As PC manufacturers discussed their own designs for DTV broadcasting, the Consumer Electronics Manufacturers Association moved to promote an industry standard for an interface between large screen televisions and personal computers. The first meeting is set for Wednesday, April 30th, at the offices of Thomson Consumer Electronics in Indianapolis, Indiana.
The CEMA Press Release included this quote from Gary Shapiro, CEMA president: "Our members are eager to develop an interface standard for the television and the computer. With consumers enjoying more electronic entertainment and information opportunities than ever before, we want to be certain there is a simple and standardized method to deliver that product," explained Gary Shapiro, president of CEMA. "To accomplish this, CEMA will work to develop product interface standards that will provide solutions to the technical inter-operability dilemmas facing television and personal computer manufacturers."
Word of a giant solar flare heading towards earth gave TV engineers another reason to be nervous. Previous solar flares have been implicated in the demise or disruption of the Telstar 401 and Anik satellites. Fortunately, the main energy in the flare missed earth. It did, however, create a colorful aurora borealis (northern lights) display seen as far south as Boston, Massachusetts.
If you are interested in the solar flare and would like to see some interesting images and movies of it, check out these sites:
Zenith, in a Press Release said it was "engaged in cooperative efforts with six transmitter manufacturers, most notably Acrodyne, ITS and LARCAN/ TTC. From their transmitter sites located atop Black Mountain, 17 miles from the city, ITS and Acrodyne will use Zenith modulation equipment to send signals to the Las Vegas Convention Center (LVCC), where they will be received by rooftop antennas and then relayed by coaxial cable to the respective booths on the convention floor. The receiving equipment as well as the video/audio decoders at both the Acrodyne and ITS exhibits are provided by Zenith."
At the Larcan booth, Zenith demonstrated a prototype modulator which, when used with a Hewlett Packard vector analyzer, was able to fed adaptive equalizer tap information back to the modulator, allowing pre-correction of transmitter, transmission line and antenna distortions.
Refer to the Press Release for more information on Zenith's pioneering efforts in digital HDTV technology.
Joe Flaherty made it clear Sunday morning that CBS' vision of the future was HDTV - maximum resolution. Monday, PC industry leaders Compaq, Intel and Microsoft presented an alternative -- starting with formats more easily handled on existing computers. Most major broadcasters were lining up behind full resolution interlaced HDTV, however, the deciding factor will be which platform delivers the "eyeballs" faster. So far, consumer TV manufacturers have been slow to provide prototype HDTV sets for public demonstrations. Indeed, if the stations on the air at NAB are counted, there are as many or more DTV stations on the air as there are TV sets to receive their signals! If PC manufacturers are able to deliver DTV receivers for the lower resolution PC video standards faster than conventional TV manufacturers can deliver TV sets or set-top converters, broadcasters will likely decide to transmit in the format that has the most viewers.
The PC manufacturers said that "digital broadcasts would be initiated using a high-definition 720p x 1280 progressive scan format for film-based materials, as well as standard definition formats in both interlaced and progressive modes." The PC group also noted that "television receivers would be substantially less expensive using this approach compared to sets using the full ATSC specification. Bob Stearns, senior vice president of technology and corporate development at Compaq said "Because this approach aligns closely with the current generation of video decompression hardware and display technology, digital television sets could be offered at price points close to today's analog sets, compared to the $3,000 to $5,000 HDTV sets that the traditional television manufacturers are planning. We think this makes more sense for the millions of consumers. The incremental cost of adding DTV reception to PCs will likely be as little as $100."
Look for more announcements about this initiative soon. More details on the NAB '97 presentation are available in a joint Press Release issued by Microsoft, Compaq and Intel.
For the immediate future, Intel and Microsoft are concentrating on data delivery using the vertical blanking interval of existing analog TV signals. Microsoft has posted details of its proposal for The Transmission of IP over the Vertical Blanking Interval (VBI) of a Television Signal on its web site. It wasn't clear how the Microsoft effort would impact the existing INTERCAST VBI system. Intel didn't mention the Microsoft proposal in a press release outlining Intel's keynote address at NAB - "The PC As The Future Of Broadcasting".
In a keynote speech at the National Association of Broadcasters Convention in Las Vegas today, Craig Mundie, senior v.p. of the consumer platforms group at Microsoft, outlined his companies bold moves into the broadcast TV arena. The first stage was Microsoft's announcement that it had reached a definitive agreement to purchase WebTV Networks, Inc. WebTV sells hardware and Internet services that allow web browsing and e-mail on conventional TV sets. Mundie also said Microsoft plans to "incorporate key broadcasting-related technology in the future versions of the Microsoft® Windows operating system." "These technologies will enable PC users to view traditional television programs, enhanced television programs and Internet broadcasts, and access innovative new services such as personalized news delivery on Windows-based PCs." More details on the NAB speech are available in the Microsoft Press Release.
Microsoft also announced that "the next releases of the Microsoft® Windows® and Windows NT® operating systems will enable PCs to receive video and digital data from existing satellite, cable and terrestrial broadcast sources. Effective with these new versions, every copy of Windows shipped is expected to include the ability to receive interactive entertainment and information delivered via the high-speed nationwide television networks. The enabling hardware for this technology is expected to add a nominal amount to the cost of PCs."
Data will be encoded in the vertical blanking interval for distribution over analog TV sources. Digital satellite and digital cable services will be able to incorporate it in their bit stream. Depending on the technology, the speeds will range from 9600 bits per second to 30 megabits per second. At its NAB booth, Microsoft demonstrated how its service could enhance conventional TV programs by providing additional information and advertising opportunities. Microsoft's press release also noted that "Internet site builders and software vendors will be able to use true push technology to broadcast multimedia-rich Internet content and software to consumers, without tying up customers' telephone lines. Virtually any kind of data could be transmitted to Windows, including software upgrades, Web site information, stock tickers, Microsoft Internet Explorer 4.0 Active Desktop content, and enhanced television programming. " More details on this technology are available in the Microsoft Digital TV Press Release and at the Microsoft Windows Web site.
Zenith announced two new integrated circuits for use in DTV sets expected to be on the market next year. The chip-set is fabricated by Zenith's parent company, LG Semiconductors, and includes two ASICs -- "one for synchonization/equalization and one for channel decoding." The Zenith Press Release described the functions of the chips: "The sync/equalizer chip locks the receiver to the VSB signal and removes both NTSC co-channel interference and multipath distortion (ghosts) from the received signal. The channel decoder chip corrects errors in the received signalusing powerful Reed-Solomon and trellis-coding error correction methods."
The Zenith VSB chips are expected to be available later this year. For more information see the Press Release.
The FCC today adopted the rules necessary to allow the new Digital TV service to begin. While the text of the Order and the new allocation table wasn't available on the FCC's Internet site, two news releases (nrmm7006.txt and nrmm7005.txt) provide some details about the new service.
The result of the proceeding, judging from the news releases, seems very positive. The FCC has managed to provide DTV channels for "all eligible existing broadcasters" while replicating existing service areas and facilitate early recovery of 60 MHz. of spectrum and eventual recovery of 138 MHz. The core spectrum approach remains, with the DTV Table being based on the use of channels 2-51 Iinstead of 7-51, proposed in the 6th NPRM). However, at the end of the transition these extra five channels would have to be returned, with DTV ending up either between channels 2 and 46 or between 7 and 51.
Responding to comments of many UHF broadcasters, the FCC has capped DTV effective radiated power at 1000 kW, average. This corresponds to peak power levels commonly used by NTSC UHF broadcasters today. Minimum power would be 50 kW.
The efforts of Low Power TV broadcasters to push the case for the service's continued existence seems to have had some affect on the Commission. Some Commissioners, in separate statements, mentioned the importance of LPTV. Commissioner Ness said "I want to enable as many LPTV stations as possible to prosper in the digital age. Perhaps one method -- where everything else fails -- would be to assemble stations on a multiplexed digital six-megahertz channel." She added "The items adopted today are not the final word on LPTV. We remain committed to doing our best to preserve these additional voices in the broadcast marketplace." Chairman Hundt offered more, noting that "We also went from doing essentially nothing for low power television and translators to adopting a number of creative measures to minimize the impact of digital television on those services. Now that the DTV allotment table is done, it is time for the Commission to explore ways to find a permanent home for the low power service." Commissioner Quello commented "I believe it is important to note that our decision here in no way prejudges what any recovered spectrum will be allocated for, and does not foreclose the possibility of its use for full power or low power broadcast services."
Will the product match the promise? We will have a better idea once the full text of the Order and the DTV Table of Allocations is available. In many ways it seems too good to be true - more protection of LPTV, more channels for reclaimation and more DTV channels for new broadcasters. Neither MSTV or the FCC was able to come up with a good allocation table for Puerto Rico. Did the engineers at OET find the answer this time? Perhaps we will know next week. If the FCC follows its usual formula for storing Orders, we can expect to find the full text of the Order at either http://www.fcc.gov/Bureaus/Mass_Media/Orders/1997/fcc97115.txt or http://www.fcc.gov/Bureaus/Engineering_Technology/Orders/1997/fcc97115.pdf. When the DTV Table of Allotments is published I plan to offer it here in the same state by state format as my popular listings of earlier tables.
If the proposals in GC Docket 97-113 are adopted, commenters will be given the option of filing their comments in FCC Rulemaking proceedings electronically, using either a World Wide Web form or electronic mail. The proposed rulemaking would not preclude filing comments on paper. The Commission sought comments on "whether these electronic filing procedures should apply to comments or pleadings concerning preliminary steps such as petitions for rulemaking, notice of inquiry proceedings, petitions for reconsideration and responsive comments or pleadings file in notice and comment rulemakings other than broadcast allotment proceedings." Initially electronically filed comments would be limited to rulemaking proceedings other than broadcast allotments. The Commission also was interesting in comments on "the feasibility and desirability of other media, such as CD-ROMs and dial-up bulletin board systems, for submitting electronic filings."
Both the news release and the Notice of Proposed Rulemaking are available on the FCC's web site.
This isn't the FCC's only electronic initiative. Last Monday, in a speech before the Land Mobile Communications Council in Washington D.C., David Horowitz, Chief of the FCC's Private Wireless Division, outlined his division's plans to move to a "Universal Licensing System: one coordinated system, designed to move licensing from the passive receipt of data to an interactive, information management tool" that will "permit all of us to stop thing in terms of forms and begin thinking in terms of information."
In a News Report released today the FCC said it had eliminated the limit on directional gain antennas for spread spectrum transmitters in the 2450 MHz. and 5800 MHz. bands. A "minimal reduction in transmitter output power for the 2450 MHz. band" is required. There were several minor changes in the rules for spread spectrum in these bands. The FCC also updated definitions of direct sequence and frequency hopping system "allowed for the operation of frequency hopping systems that incorporate intelligence thereby permitting the system to recognize other users within the spectrum band so that it individually and independently chooses and adapts its hopping sequence to avoid hopping on occupied channels."
See the News Report for a summary of the action or the Report and Order for all the details.Microsoft Corporation Senior Vice President Craig Mundie will be one of the keynote speakers at the National Association of Broadcasters (NAB) Multimedia World Conference at the Sand Convention Center in Las Vegas. In an address Sunday, Mundie will outline Microsoft's digital broadcasting strategy. "Key enabling technologies for the digital broadcasting infrastructure" will be demonstrated. The presentation will be held in Sands Convention Center Room 105. The keynote speech will also be available live on Microsoft© Netshow® server at http://www.microsoft.com/netshow/events.htm. For more details see the Microsoft Press Release.
Dr. William Gray and his team of scientists at the Department of Atmospheric Science at Colorado State University reported that "Information obtained through March 1997 indicates that as during the previous two seasons the coming 1997 Atlantic hurricane season is again likely to have greater than average activity." However, the report also said "Whereas net 1997 tropical cyclone activity is expected to be 110 percent of the long term average, conditions should be relatively quiet in comparison with the unusually active 1995 and 1996 seasons. Still, 1997 should be significantly more active than the average of the generally suppressed hurricane seasons during the last 25 years and especially in comparison to the particularly quiet seasons of 1991-1994." See Dr. Gray's Early April Forecast of Atlantic Basin Seasonal Hurricane Activity for 1997 for more detailed information.
A research team headed by professor Philip Krein at the University of Illinois at Urbana-Champaign has developed a new process for battery charge equalization that has the potential to double the life of rechargable batteries. The process "uses a group of capacitors and transistorized switching networks to shift the charge among adjacent battery cells..." The process works during both the charge and discharge cycles. By balancing the charge and discharge current among all cells, weaker cells can be fully charged without overcharging the stronger cells. Users of Ni-cad battery packs are familiar with this problem. The researchers have filed for a patent on the technology. More information is available in UIUC's News Release.
Zenith Applauds Final FCC Action on DTV - Big Screen Sets in '98 - Set-Top Boxes Planned (Apr. 4)
E-Town News Story: FCC Approves HDTV Channels (Apr. 4)
CEMA Applauds FCC DTV Action - Says Set Sales to Begin in Late '98 (Apr. 3)
E-Town News Story Lists TV Stations to Begin DTV Broadcasting in '98 (Apr. 3)
Andrew Introduces New 6-1/8" and 3-1/8" Rigid Line Hinged Hangers (Apr. 7)
S. A. Introduces PowerVu Command Centre 3000 with DVB Scrambling Support (Apr. 3)
S. A. Shows Internet Access and File Transfer with PowerVu Digital System (Apr. 3)
Scientific Atlanta NAB Booth Overview (Apr. 2)
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Last modified April 28, 1997 by Doug Lung dlung@transmitter.com
Copyright © 1997 H. Douglas Lung