AN243 Datasheet, PDF (1/16 Pages) Silicon Laboratories – Describe the high-level differences between RDS and RBDS

AN243
USING RDS/RBDS WITH THE Si4701/03
1. Scope
This document applies to the Si4701/03 firmware revision 15 and greater. Throughout this document, device refers
to an Si4701 or Si4703.
2. Purpose
 Provide an overview of RDS/RBDS
 Describe the high-level differences between RDS and RBDS
 Show the procedure for reading RDS/RBDS data from the Si4701
 Show the procedure for post-processing of RDS/RBDS data
 Point the reader to additional documentation
3. Additional Documentation
[1] The Broadcaster's Guide to RDS, Scott Wright, Focal Press, 1997.
[2] CENELEC (1998): Specification of the radio data system (RDS) for VHF/FM sound broadcasting.
EN50067:1998. European Committee for Electrotechnical Standardization. Brussels Belgium.
[3] National Radio Systems Committee: United States RBDS Standard, April 9, 1998 - Specification of the radio
broadcast data system (RBDS), Washington D.C.
[4] Si4701-B15 Data Sheet
[5] Si4703-B16 Data Sheet
[6] Application Note “AN230: Si4700/01/02/03 Programming Guide”
[7] Traffic and Traveller Information (TTI)—TTI messages via traffic message coding
(ISO 14819-1) Part 1: Coding protocol for Radio Data System—Traffic Message Channel (RDS-TMC) using ALERT-C
(ISO 14819-2) Part 2: Event and information codes for Radio Data System—Traffic Message Channel (RDS-TMC)
(ISO 14819-3) Part 3: Location referencing for ALERT-C
(ISO 14819-6) Part 6: Encryption and conditional access for the Radio Data System—
Traffic Message Channel ALERT C coding
[8] Radiotext plus (RTplus) Specification
4. RDS/RBDS Overview
The Radio Data System (RDS*) has been in existence since the 1980s in Europe, and since the early 1990s in
North America as the Radio Broadcast Data System (RBDS). In 1998, the US and Europe spurred RDS adoption
rates by largely unifying the existing RDS and RBDS standards.
Since the 1998 unifying amendments, RDS has gained substantial market adoption in the US, Europe, and other
countries worldwide. It is standard in vehicles and radio equipment from many leading manufacturers. The cost to
enable a broadcast station with RDS can be less than $500, and many North and South American, European, and
Asian radio stations broadcast with some RDS capability. And with extremely small, power-efficient RDS solutions
such as the Si4701/03, RDS is making in-roads in many millions of portable devices such as handsets, portable
radios, and portable music/media players.
RDS is an auxiliary signal to the FM broadcast system. As it is auxiliary, the modulated signal must not degrade the
primary audio signal, and so RDS is typically only decipherable on strong broadcasts. Figure 1 depicts the FM
broadcast components. At the far left of the graphic the mono signal is broadcast with the greatest strength or
deviation in kHz along the y-axis. This means that a signal will first be received and output in mono until the FM
signal is clear enough for the FM receiver to demodulate the stereo signals. RDS is broadcast with the least
Rev. 0.2 3/07
Copyright © 2007 by Silicon Laboratories
AN243