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Clear Channel: 5kHz for AM
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Radio Advertising Bureau Gives Thumbs Up to IBOC
During its semiannual meeting in New York City in September, the Board of Directors of the Radio Advertising Bureau (RAB) passed a resolution voicing its support of the industry's move toward wide-scale implementation of IBOC digital broadcasting using Ibiquity's HD Radio system.
The resolution noted that the RAB "recognizes the efforts of all radio broadcasters employing IBOC [HD] Radio, technology that brings a new and improved digital sound to radio stations nationwide. Further, the Board encourages the same broadcasters continue to educate their listeners on the benefits of the new digital sound."
The Radio Advertising Bureau (RAB) is the sales and marketing arm of the Radio industry with nearly 7,000 members including close to 6,000 stations in the U.S., and more than 1,000 associate members in networks, representative firms, sales, and international organizations.
Radio Reading Service Says Yes to IBOC
IBOC deployment found favor with yet another constituency, as the International Association of Audio Information Services (IAAIS) board of directors recently issued its resolution of support for Ibiquity's HD Radio system.
The IAAIS is the organization that has long promoted the transmission of radio reading services for the blind on the analog SCA subcarrier channels of many FM public broadcasters. The group has worked closely with NPR's Tomorrow Radio Project in researching new codecs and their suitability for use with voice-grade services at speeds as low as 12.5kb/s. These ultra-low data rates could allow HD FM Radio broadcasters to carry the service without sacrificing audio quality on their primary digital program channel, potentially increasing the pool of broadcasters willing to carry the service. The development would also allow potential listeners to use off-the-shelf digital receivers instead of the specialized analog SAC receivers now required.
IBOC or IBAC? IEEE Symposium to Examine Alternate Digital Approach
A broadcast symposium to be hosted by the Institute of Electrical and Electronic Engineers (IEEE) in Washington next week may throw a new wrinkle in America's IBOC digital roll-out, as a German researcher suggests that in-band adjacent-channel (IBAC), not in-band on-channel, could be the best architecture for a compatible DAB standard on FM.
Claus Kupferschmidt, of Germany's Hanover University, is scheduled to deliver a recent paper entitled A New DAB Scheme for the FM Band Based on Continuous Phase Modulation during the Digital Radio Broadcast Systems session to be held on Oct. 14. The presentation will outline a proposal to use a modulation technique known as Continuous Phase Modulation (CPM) to achieve data rates of up to 200kb/s. While the technique reportedly encroaches on first-adjacent channels, Kupferschmidt claims that the system is fully compatible with current FM band plans utilizing 200kHz channels. CPM is an attractive modulation scheme because it can reportedly withstand amplification by non-linearized FM transmitters currently in use at most FM broadcast outlets, while the ODFM used in Ibiquity's HD Radio FM system requires less efficient linear amplification.
Assuming the system can actually deliver the performance suggested in the papers abstract, it might prove attractive to broadcasters looking to minimize the economic cost of digital conversion, while achieving an ultimate data rate significantly higher than that of hybrid FM HD Radio. Even though such a proposal may have arrived too late in the adoption process to impact the favored U.S. standard, it's likely to receive close scrutiny by the broadcast engineering community.
Industry insiders familiar with the long developmental history of IBOC digital transmission in the US may recall that IBAC schemes were originally among early proposals for compatible DAB, but were abandoned in favor of the current approach.
The symposium, which also includes sessions on broadband audio/video distribution, broadcast antenna technology, and DTV, runs Oct. 13 to 15 at the Hotel Washington in downtown DC. For registration and other information, visit the organization's website at www.ieee.org/organizations/society/bt/symp/fullprogram.html.
DRS to Host DRM Symposium
DRS Broadcast Technology, formerly Continental Electronics, will host a Digital Radio Mondiale (DRM) symposium on Nov. 12 in Dallas. The symposium is aimed at broadcasters and manufacturers in the Western hemisphere interested in learning more about DRM implementation. The event will convene a number of DRM officials and experts for a discussion of technical, regulatory, manufacturing and marketing aspects of the technology, including an interactive, roundtable discussion with North and South America experts designed to provide attendees answers to specific questions about roll-out of the new technology. A live demonstration of DRM broadcasting will also be conducted during the symposium.
DRM is a non-proprietary, universally standardized, digital radio system for short-wave, medium-wave and long-wave AM transmission. More than 60 broadcasters - commercial, public, international, national and local - have already commenced DRM broadcasts worldwide. The DRM Consortium has 85 Members from 27 countries, including Canada, Ecuador, and the U.S.A.
Watch the Industry Events calendar on the Radio magazine website for registration information once it is available.
Audemat-Aztec Licenses HD Radio Technology
North Miami Beach, FL, and Columbia, MD - Oct 1, 2004 - Audemat-Aztec has licensed Ibiquity's HD Radio technology for inclusion into Audemat-Aztec's radio test and monitoring products. As a result, Audemat-Aztec will be able to further assist AM and FM broadcasters in the initial transition to digital and maximize the benefits of their digital signals by offering mobile products capable of measuring coverage and analyzing quality of HD Radio reception.
Audemat-Aztec states that it received many requests from U.S. customers to develop a mobile RF field strength meter to measure coverage and analyze quality of HD Radio reception. This product, which has been named NavIBOC, is being designed and will be available for sale at NAB2005.
SRS Makes Surround Inroads with Honda
Honda is offering its new multichannel car surround A/V system with SRS Labs' Circle Surround II (CS II) for Automotive as a dealer option for all new model cars sold in Japan. The Honda entertainment and navigation control system, manufactured by Fujitsu Ten, can deliver up to four-channel surround sound in any multi-speaker car environment. The dealer option sound system is also now available to consumers in Japan who own older model Hondas and wish to upgrade their entertainment systems.
Most cars are equipped with four or more speakers and yet are unable to experience surround sound. Circle Surround II claims to solve the problem by creating a phantom center channel for cars with no center speaker. The system will also deliver surround sound over more than four speakers if the car is so equipped. When playing surround content, SRS says Circle Surround II can provide a home-theater experience in an automobile.
Movement toward the introduction of OEM surround audio by large automakers like Honda is of great interest to domestic HD Radio broadcasters, since Ibiquity has certified SRS' CS matrix-encoded system as an HD Radio compatible technology. Broadcasters seem equally intrigued by the emerging development of an FM HD Radio standard for discrete 5.1 Surround by Fraunhoffer. In addition, Harris has been working with Neural on a surround system, and Orban has hinted that it is working on a system as well.
IBOC Across America
IBOC By State: California
Ibiquity has a list of stations that have licensed HD Radio technology and notes those that are on the air now. IBOC by State will look at various states and list the stations that are making the transition.
|Station ||Format ||Market ||Owner ||On Air|
|KAZN-AM 1300 ||Asian ||Los Angeles ||Multicultural Radio Broadcasting Group ||No|
|KCRW-FM 89.9 ||Educa/News ||Los Angeles ||Santa Monica Community College ||No|
|KCSN-FM 88.5 ||Classical ||Los Angeles ||California State University ||Yes|
|KDSC-FM 91.1 ||Classical ||Los Angeles ||University of Southern California ||Yes|
|KIIS-FM 102.7 ||Top 40 ||Los Angeles ||Clear Channel Radio ||Yes|
|KKBT-FM 100.3 ||Urban ||Los Angeles ||Radio One ||Yes|
|KKJZ-FM 88.1 ||Jazz ||Los Angeles ||California State University ||No|
|KMNY-AM 1600 ||BNw/Eth/ASt ||Los Angeles ||Multicultural Radio Broadcasting Group ||No|
|KMXE-AM 830 ||Spn/Tlk/Nws ||Los Angeles ||Radiovisa ||Yes|
|KMZT-FM 105.1 ||Classical ||Los Angeles ||Mount Wilson FM Broadcasters ||No|
|KNX-AM 1070 ||News ||Los Angeles ||Infinity Broadcasting ||No|
|KOST-FM 103.5 ||AC ||Los Angeles ||Clear Channel Radio ||Yes|
|KPCC-FM 89.3 ||Nws/Tlk/Inf ||Los Angeles ||Pasadena Area Community College ||No|
|KROQ-FM 106.7 ||Alternative ||Los Angeles ||Infinity Broadcasting ||Yes|
|KSCA-FM 101.9 ||Ranchera ||Los Angeles ||Univision Radio ||Yes|
|KSUR-AM 1260 ||Adlt Stndrd ||Los Angeles ||Mount Wilson FM Broadcasters ||No|
|KTNQ-AM 1020 ||Span/Varty ||Los Angeles ||Univision Radio ||Yes|
|KUSC-FM 91.5 ||Classical ||Los Angeles ||University of Southern California ||Yes|
|KWVE-FM 107.9 ||Christian ||Los Angeles ||Calvary Chapel Church ||No|
|KCRY-FM 88.1 ||Educa/News ||Mojave ||Santa Monica Community College ||No|
|KAZU-FM 90.3 ||Variety ||Monterey-Salinas-Santa Cruz ||California State University ||No|
|KPSC-FM 88.5 ||Classical ||Palm Springs ||University of Southern California ||Yes|
|KCRI-FM 89.3 ||Educa/News ||Riverside-San Bernardino ||Santa Monica Community College ||No|
|KUOR-FM 89.1 ||Jazz ||Riverside-San Bernardino ||The University of Redlands ||No|
|KQEI-FM 89.3 ||Nws/Tlk/Inf ||Sacramento ||KQED ||No|
|KVMR-FM 89.5 ||Variety ||Sacramento ||Nevada City Community Broadcast Group ||No|
|KXJZ-FM 88.9 ||Jazz/News ||Sacramento ||California State University ||No|
|KXPR-FM 90.9 ||Classical ||Sacramento ||California State University ||No|
|KXSR-FM 91.7 ||Classical ||Sacramento ||California State University ||No|
|KALW-FM 91.7 ||Nws/Tlk/Inf ||San Francisco ||San Francisco Unified School District ||No|
|KCBS-AM 740 ||News ||San Francisco ||Infinity Broadcasting ||Yes|
|KCSM-FM 91.1 ||Jazz ||San Francisco ||San Mateo County Community College ||Yes|
|KDFC-FM 102.1 ||Classical ||San Francisco ||Bonneville International ||Yes|
|KFFG-FM 97.7 ||AOR ||San Francisco ||Susquehanna Radio ||Yes|
|KFOG-FM 104.5 ||AAA ||San Francisco ||Susquehanna Radio ||Yes|
|KKSF-FM 103.7 ||Smooth Jazz ||San Francisco ||Clear Channel Radio ||Yes|
|KMZT-AM 1510 ||Classical ||San Francisco ||Mount Wilson FM Broadcasters ||No|
|KOIT-FM 96.5 ||Soft AC ||San Francisco ||Bonneville International ||Yes|
|KQED-FM 88.5 ||Nws/Tlk/Inf ||San Francisco ||KQED ||No|
|KSAN-FM 107.7 ||Clsc Rock ||San Francisco ||Susquehanna Radio ||Yes|
|KYLD-FM 94.9 ||CHR/Dance ||San Francisco ||Clear Channel Radio ||No|
|KZBR-FM 95.7 ||Country ||San Francisco ||Bonneville International ||Yes|
|KEMR-FM 105.7 ||Span/Rock ||San Jose ||Univision Radio ||Yes|
|KQSC-FM 88.7 ||Classical ||Santa Barbara ||University of Southern California ||Yes|
|KUOP-FM 91.3 ||Nws/Tlk/Inf ||Stockton ||University of the Pacific ||No|
|KYKL-FM 90.7 ||ChrsContemp ||Tracy ||Educational Media Foundation ||No|
Eye on IBOC
Mexico Testing AM IBOC
Broadcast Electronics is currently participating in tests of the HD Radio AM system in Mexico. The tests are being conducted in cooperation with the Cámara de la Industria de Radio y Televisión (CIRT) and Grupo Radio Centro, Mexico's leading radio broadcaster with 11 stations in Mexico City. This follows five months of testing of a BE-equipped HD Radio FM system on the group's XHFAJ-FM, which was concluded in early 2004.
A Broadcast Electronics ASi 10 HD Radio signal generator was installed on the 100kW transmitter of XEN-690 in Mexico City on Aug. 31. Several months of field testing will be conducted on the AM system, and the results of both the AM and FM tests will be given to the Secretaría de Comunicaciones (SCT), the government agency that oversees broadcasting in Mexico, for the purpose of selecting a national digital radio standard. The SCT is expected to choose an AM and FM digital standard in 2005.
"Hundreds of thousands of measurement points and nine hours of video and audio have been recorded for the FM, and I expect the AM will go through similar rigorous testing," commented John Schneider, Broadcast Electronics' sales manager for Latin America and the Caribbean.
AM and FM channel spacing is narrower in Mexico than in the United States, which presents unique challenges to IBOC implementation. Improved sound quality will be the focus of testing, according to Eduardo Stevens, director of engineering for Grupo Radio Centro.
The AM system will be demonstrated to industry leaders at the CIRT's national fall convention in Mexico City, which will be held from Oct. 6 to 8. Attendees will receive a full report on the FM field test results at that time.
Public Radio Outlet Airs First Live Surround Concert via IBOC
Denver's KUVO-FM made history on the evening of Sept. 25, becoming the first radio station to broadcast a live concert in digital surround sound.
Featuring the music of Grammy Award-winning vocalist Diane Reeves, the entire concert was carried live on the station's IBOC signal with underwriting backing from receiver manufacturer Kenwood USA and audio retailer Ultimate Electronic-SoundTracks. Kenwood has been a key partner in NPR's Tomorrow Radio Project, along with Harris, which provided the Harris/Neural Neustar audio processor and a Neural 5.1 surround encoder.
The details of the broadcast will be featured in an upcoming article in Radio magazine.
HD Radio Terminology
An Introduction to the New Language Surrounding HD Radio
interleaved antenna: An FM antenna configuration that allows two identical antenna configurations to be mounted in the same axis, with alternating antenna bays spaced at half-wave intervals to reduce mutual coupling. This arrangement allows an FM IBOC digital transmitter and a conventional analog transmitter to combine their signals for hybrid operation without the need for large, inefficient multiport combiners, although a ferrite circulator is generally required to provide sufficient isolation between antenna and the digital transmitter output stage.
Harris Brings HD Radio Roadmap to NAB in San Diego
Harris plans to showcase a number of new products at the NAB Radio Show, which begins today. Among the offerings will be several lines that the company says are specifically designed to ease the transition from analog to HD Radio broadcasting. Some of the featured items in this roadmap portfolio are the Flexstar applications importer and exporter, a demonstration of Harris' proprietary Split-Level Combining technology, and a display of Harris' Neustar product line.
The first two Flexstar components to debut at NAB Radio are the Flexstar HDI-100 data importer and the Flexstar HDE-100 program exporter. The HDI-100 importer accepts advanced application services, including supplemental program audio streams and is designed to enable the addition of new services. The HDE-100 exporter multiplexes data from the importer with a station's main program channel, producing a single bandwidth-efficient bitstream for the HD Radio exciter. Both the importer and the exporter are compatible with Harris' Dexstar HD Radio exciter.
Harris will also host a split-level combining demonstration; an innovation that allows an FM radio station to upgrade to HD Radio with its existing FM transmitter, even if the existing transmitter lacks the headroom necessary for traditional high-level combining. A description of the Split-level Combining appeared in the July 2004 issue of Radio magazine. You can read the article at this link. The demonstration will be available via the Internet through Harris' ECDI transmitter network monitoring and control system.
Clear Channel: 5kHz for AM
Cincinnati – Sep 29, 2004 – A memo sent to the Clear Channel Radio engineers from Jeff Littlejohn, senior VP of engineering for Clear Channel, spells out a plan for all the Clear Channel AM stations to reduce their audio bandwidth to 5kHz or 6kHz, depending on the station's format. Littlejohn based the decision on his own listening experience during IBOC tests with WLW (700) Cincinnati and WR (710) New York.
An excerpt from his memo:
During those tests, we limited both stations to 5kHz audio bandwidth and then turned on and off the IBOC carriers at 1-minute intervals. The result was pretty interesting! When I tuned to 710 AM, I heard WOR-AM's skywave crystal clear! Never in the dozen years of living in Cincinnati had I heard WOR's skywave signal. It had always been obliterated by the sidebands of WLW.
Next, I tuned to WLW 700, I couldn't perceive any audible degradation by limiting the audio to 5kHz. Suddenly, it struck me that radio had lost the battle that was fought in 1987 through 1991. That was the time period when we argued with the CEA, [the] NAB and [the] NRSC about a couple of new AM Audio standards, NRSC-1, NRSC-2 and NRSC-3. I remember complaining about how much limiting our audio sidebands to 10kHz was going to degrade the performance of AM. NAB wanted to retain 15kHz audio, CEA wanted us to reduce our audio bandwidth to 5kHz. In the end, we settled on 10kHz audio and later the FCC adopted the standard as the new bandwidth requirement.
The goal of NRSC was laudable and was intended to result in wider bandwidth receivers, but the fact is that nobody ever made more than a handful of these wider-bandwidth receivers. Instead, the receiver manufacturers continued to reduce the audio bandwidth of AM receivers to eliminate the "chatter" caused by the sidebands of adjacent channels. The result is that an "above average" receiver today has audio response that is less than 4.5kHz. In fact most have audio response that is down 10 to 12dB at 5kHz, and the roll off can start at around 2kHz.
Littlejohn's memo goes on to question to logic of transmitting a 10kHz signal when dew if any listeners can receive anything above 4.5kHz. He cites that reducing the audio bandwidth will improve modulation efficiency, reduce interference to first-adjacent channels, and reduce the noise floor in the bandwidth-limited receivers.
Because of this, Littlejohn "can find no good reason to maintain 10kHz audio bandwidth" and that there are "substantive benefits" to stations reducing their audio bandwidth to match the passband of AM receivers. He has called for a standard operating practice for all Clear Channel AM stations.
All stations with modern audio processors will reduce their bandwidth to 5kHz, except for those stations with music-intensive format, which will be reduced to 6kHz.
Stations that do not have a modern processor that is capable of the reduction in audio bandwidth will be given favorable review to any request for a replacement audio processor.
Littlejohn adds, "It is true that AM HD Radio is going to require that we reduce our audio bandwidth to 5kHz...to properly implement that technology. However, this change has nothing to do with HD Radio. It's the right thing to do for AM analog radio service. HD Radio just happened to point out that the benefit existed."
Littlejohn is the co-chairman of the NRSC's AM subcommittee, and in his memo he states that he will propose this standard practice among all AM licensees. He wants Clear Channel to "be the leader in this effort to clean up the AM analog service."
Comments have already risen regarding this action. Some comments received at Radio magazine don't agree with Littlejohn's assessment of an unnoticeable impact from the reduced audio bandwidth. Other comments don't believe the claim that the move is irrelevant to the HD Radio analog signal requirements, and that this is one way to make analog AM sound worse so that AM IBOC will show a marked audio improvement over analog.
There are merits to what Littlejohn proposes, but as he pointed out, the idea is not really new one. It will cause some stir for a few days and maybe weeks, but the buzz will likely die down very soon.
To receive these articles twice a month in your e-mail, subscribe to the IBOC Update - Insight on HD Radio e-newsletter. Click here to subscribe.