NRSC
Adopts Updated RBDS Standard
The Radio Data
System (RDS) FM subcarrier-based data broadcasting Standard was
first introduced in Europe in 1984 and its continuing, widespread
usage and relevancy is a testament to its robust and forward-looking
design (see the July
12, 2010 issue of Radio TechCheck for additional background
information on RDS). Last Saturday, the National Radio Systems Committee
(NRSC) adopted an update to the U.S. version of the Standard (called
RBDS, for Radio Broadcast Data System). Notably, this
new version includes support for the latest RadioText+
technology, some new Program Type (PTY) codes which
better reflect new programming choices available to listeners and
a new, optional method for Program Information (PI)
code generation.
NRSC-4-B, United
States RBDS Standard Specification of the Radio Broadcast
Data System (RBDS), was adopted by the Radio Broadcast Data
System (RBDS) Subcommittee at the April 9, 2011 meeting of the group,
held in conjunction with the 2011 NAB Show. The Subcommittee is
chaired by Barry Thomas, vice president of engineering, radio, Lincoln
Financial Media. This latest version of the Standard was developed
by the subcommittees RDS Usage Working Group (RUWG), chaired
by Steve Davis, senior vice president, engineering and capital management,
Clear Channel Broadcasting, Inc. Also providing input was the RDS
Forum, an industry-sponsored organization based in Europe responsible
for maintaining the RDS Standard (designated IEC 62106).
NRSC-4-B includes
only those sections which differ from the European version of the
Standard, IEC 62106, Specification of the Radio Data System
(RDS) for VHF/FM sound broadcasting in the frequency range from
87.5 to 108.0 MHz. This is a departure from previous versions
of the NRSC Standard (NRSC-4-B is the fourth NRSC version) which
included nearly all of the text from the IEC version except for
a few, important modifications specific to the U.S. version. This
new approach will simplify design and development of compatible
devices by transmission equipment and receiver manufacturers since
it will now be much easier to see what the differences are between
the U.S. and European versions. Since manufacturers of RDS-enabled
devices typically serve both markets, this is expected to be a welcome
change.
Some of the
most important changes in the NRSC-4-B Standard include the following:
RadioText+ this is an open data application
and one of the most recent features to be added to European version
of the Standard. RadioText+ makes it possible for receivers to parse
and identify text information sent over RDS using the RadioText
feature. The recent implementation of RDS tagging by
such devices as the Apple iPod Nano utilizes RadioText+ features,
and the RDS Forum is encouraging application developers to make
use of this powerful new feature. An RDS Forum presentation prepared
in January 2011 entitled Progress on the RT+ Implementation
is available for download here.
Program
Type (PTY) codes three new codes have been
added, which better reflect new programming choices available to
listeners. They are Spanish Talk (Call-in shows, interview
programs, etc., in the Spanish language), Spanish Music
(Music programming in the Spanish language) and Hip-Hop
(Popular music incorporating elements of rap, rhythm-and-blues,
funk, and soul).
Optional
Program Information (PI) code modification
a new provision has been added for broadcasters who are transmitting
traffic information using the TMC open data application. The Standard
now supports an optional method for PI code calculation, allowing
for substitution of 0x01 for the first nibble of the
PI code. Doing so will make the TMC transmission compatible with
a greater variety of traffic information receivers because many
such receivers interpret a first nibble of 0x01 as an indication
that the receiver is in North America, consistent with the Location
Table definition contained in the TMC specification. It was noted
by the RUWG, when deliberating this change, that some receivers
which use the PI code to determine the station call sign (by back-calculation)
might behave incorrectly if the 0x01 substitution is made. However,
since few (if any) receivers implement call sign back-calculation,
there was little concern within the group that this would be an
issue.
The updated
Standard will be available free-of-charge on the NRSC's
website, following a final, procedural review which will take
approximately two weeks. Additional information about the NRSC,
including information on becoming a member, is also available on
the website. With the update to the Standard completed, the RUWG
is now turning attention to the development of an RDS Usage Guideline
please contact David Layer,
senior director, advanced engineering with NAB Science and Technology
if you would like to be involved in this important work.
|