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February 28, 2011
Dennis Wharton
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FM-Band HD Radio Technology for Improving Digital Coverage Tested

--NAB FASTROAD-funded project tests asymmetric sideband performance on Boston, MA station--

WASHINGTON, D.C. -- NAB FASTROAD today announced the release of a report on field testing of HD Radio asymmetric sideband technology for FM-band digital radio. This work was undertaken by iBiquity Digital Corporation, developers of the HD Radio IBOC system used by U.S. broadcasters to transition to digital radio, and was co-funded by iBiquity and NAB FASTROAD.

The report, entitled "FM HD Radio Field Performance With Unequal Digital Sideband Carrier Levels (Preliminary)," characterizes the digital coverage improvement that may be realized by a typical FM Class B broadcaster using asymmetric (unequal) IBOC transmission power. This new (and at present, experimental) transmission method affords broadcasters the ability to mitigate potential first-adjacent digital-to-analog interference by allowing independent adjustment of upper and lower IBOC digital sideband levels, maximizing the digital signal coverage area as a result.

Greater Media station WKLB, located in the Boston, MA market, was used to host these tests. iBiquity is in the process of conducting some additional laboratory tests, the results of which will be released soon. While asymmetric sideband operation is not yet permissible under FCC rules (except by experimental authorization), these test results will provide a basis for requesting a rules modification allowing for use of this digital coverage-improving technology.

The full text of this report and information on the NAB FASTROAD technology advocacy program are available at Inquiries on these results are encouraged - please contact NAB Science & Technology Senior Director, Advanced Engineering David Layer at

NAB FASTROAD (Flexible Advanced Services for Television & Radio On All Devices) is the technology advocacy program of the National Association of Broadcasters. The overall mission of the FASTROAD program is to seek and facilitate development and commercialization of new technologies that can be exploited by broadcasters using radio and television broadcast spectrum.

About NAB
The National Association of Broadcasters is the premier advocacy association for America's broadcasters. NAB advances radio and television interests in legislative, regulatory and public affairs. Through advocacy, education and innovation, NAB enables broadcasters to best serve their communities, strengthen their businesses and seize new opportunities in the digital age. Learn more at

About iBiquity Digital
iBiquity Digital Corporation is the developer of HD Radio Technology, which is fueling the digital radio revolution in the United States and around the world. The digital technology enables broadcasters to offer new and unique FM content via HD2/HD3 channels, crystal-clear sound and data services on both the AM and FM bands - all free, with no subscription fee. Leading broadcasters, consumer electronics manufacturers, automakers and retailers are committed to HD Radio Technology. iBiquity Digital is a privately held company with operations in Columbia, MD, Auburn Hills, MI, and Basking Ridge, NJ. For more information, please visit and


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