AM & FM IBOC (digital radio)
Kenwood
IBOC Background:
Broadcast Signal Lab is actively involved in the development of new digital communications technologies.
Broadcast Signal Lab is a member of the National Radio Systems Committee and has contributed David Maxson's
expertise to the NRSC Digital Audio Broadcasting Subcommittee as it oversees the testing, evaluation & standards-setting
for the new In-Band, On-Channel (IBOC) technology. The core "NRSC-5" standard was adopted in April 2005 and published soon thereafter. It is available at no charge on the NRSC Standards web page. Additions to the standard are forthcoming.
IBOC technology sends high quality digital signals over the same airwaves that analog AM and FM radio use today.
These digital signals can be picked up by new digital radios while they have little impact on traditional analog reception.
The proper generic name for the service is "IBOC". The brand name "HD
RadioTM" is owned by IBiquity
Digital Corporation. iBiquity invented the core IBOC technology that
is being standardized by the NRSC, and reportedly only grants the HD Radio
name to licensees who use iBiquity's software. Companies that manufacture
NRSC-5 compliant transmitters or receivers can design their own software/hardware
to be NRSC-5 compliant, but they may not be able to earn the HD Radio
name.
Broadcast Signal Lab's decade-long participation in digital radio efforts has resulted in numerous
technical papers and presentations.
IBOC Technology:
Data Services
Broadcast Signal Lab has collaborated with Impulse Radio,
the company that has developed the technology for managing, moving, and making money with data transmissions over AM & FM
IBOC. Once a standard is adopted, look for Impulse Radio's open data transport protocol to be implemented in transmitters
and receivers. This protocol creates an open platform that can be shared by competing services, all under the broadcaster's
control.
Links to Data Papers and Slides
Equipment
Kenwood USA manufactures a line of automobile radios, many of which can have an IBOC radio module connected to them. These
are HD radio certified devices. Broadcast Engineers can use Kenwood car radios to perform certain diagnostics on their
transmitted IBOC signals.
A special Kenwood Application Note
describes the special keystrokes to turn broadcaster mode.
Broadcast Signal Lab documented this procedure in more detail in a
Companion Application Note.
Nautel Corporation manufactures FM IBOC transmitters with a radio frequency precorrection feedback loop that does a marvelous job of
minimizing out of band emissions. Broadcast Signal Lab evaluated a Nautel transmitter at KUVO in Denver and reported
on the results.
Measurement techniques for IBOC signals have been explored at Broadcast Signal Lab, resulting in articles, papers, and presentations.
Power Measurement and Occupied Spectrum
Links to Useful Sites
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