Autofahrer-Rundfunk-Informationssystem
Encyclopedia
Autofahrer-Rundfunk-Informationssystem (ARI) was a system for indicating the presence of traffic information in FM broadcasts
used by the German
ARD
network of FM radio stations from 1974. Developed jointly by IRT
and Blaupunkt
, it indicated the presence of traffic announcements through manipulation of the 57kHz subcarrier
of the station's FM signal.
ARI was rendered obsolete by the more modern Radio Data System
and the ARD stopped broadcasting ARI signals on March 1, 2005.
An ARI-equipped radio would illuminate an indicator lamp to show that this function was in force. Most such radios would use this function further to help users search for ARI broadcasts. In the Radio Data System
environment, the TP signal is equivalent to this basic function.
The basic method implemented on an analog receiver would be a switch usually marked SDK or VF. Radios that used the "classic" mechanical push-button preset system would have one of these buttons set aside as the VF switch. If this switch was on, the radio would mute unless it was tuned in to a station that transmitted this signal.
If the radio was a digitally-tuned receiver, this switch usually engaged an "ARI-seek" mode which had the radio seek for any ARI station if it was out of range of the currently-tuned ARI station.
A radio that used a "DK" switch, often part of the "SDK" or "VF" switch, was placed in to "traffic-priority" mode. It would pick up on this signal and come out of a muted state or cut over a tape or CD that was playing and play the announcement at a fixed volume level.
There was the ability to switch off such announcements on these sets if the driver found a particular announcement irrelevant or it ran on for too long, but it was not easily explained to people new to the system. This was also confusing because a lot of cheaper implementations used a mechanical toggle switch to engage / disengage ARI mode and it was hard to simply use this switch simply to reset the system.
The set would indicate the current zone that it was in rather than using an "SK" indicator whenever it was on an ARI station. As well, the user could control ARI search behavior based on the current zone, a user-nominated zone such as the neighboring zone or any ARI station in any zone.
was the station designated for such broadcasts, and ads for new Blaupunkt car stereos announced it, but just like in the U.S., ARI did not seem to catch on.
FM broadcasting
FM broadcasting is a broadcasting technology pioneered by Edwin Howard Armstrong which uses frequency modulation to provide high-fidelity sound over broadcast radio. The term "FM band" describes the "frequency band in which FM is used for broadcasting"...
used by the German
Germany
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...
ARD
ARD (broadcaster)
ARD is a joint organization of Germany's regional public-service broadcasters...
network of FM radio stations from 1974. Developed jointly by IRT
Institut für Rundfunktechnik
The Institut für Rundfunktechnik GmbH is the research centre of the German broadcasters , Austria's broadcaster and the Swiss public broadcaster . It is located in Munich and is responsible for the research and standardisation of broadcasting technology...
and Blaupunkt
Blaupunkt
GmbH is a German manufacturer of electronics equipment, noted for its home and car audio equipment. It was a 100% subsidiary of Robert Bosch GmbH until March 1st, 2009 when its Aftermarket and Accessories branch including the brand name were sold to Aurelius AG of Germany for an undisclosed...
, it indicated the presence of traffic announcements through manipulation of the 57kHz subcarrier
Subcarrier
A subcarrier is a separate analog or digital signal carried on a main radio transmission, which carries extra information such as voice or data. More technically, it is an already-modulated signal, which is then modulated into another signal of higher frequency and bandwidth...
of the station's FM signal.
ARI was rendered obsolete by the more modern Radio Data System
Radio Data System
Radio Data System, or RDS, is a communications protocol standard for embedding small amounts of digital information in conventional FM radio broadcasts. RDS standardises several types of information transmitted, including time, station identification and programme information.Radio Broadcast Data...
and the ARD stopped broadcasting ARI signals on March 1, 2005.
SK signal
The SK signal is actually the 57 kHz subcarrier that is transmitted by the ARI-compliant FM station for this functionality. This frequency, like the RDS subcarrier frequency is chosen because it is the third harmonic of the 19 kHz pilot tone used in the FM-stereo transmission standard. An easy way to understand that is that this frequency is the 19 kHz pilot tone multiplied by 3.An ARI-equipped radio would illuminate an indicator lamp to show that this function was in force. Most such radios would use this function further to help users search for ARI broadcasts. In the Radio Data System
Radio Data System
Radio Data System, or RDS, is a communications protocol standard for embedding small amounts of digital information in conventional FM radio broadcasts. RDS standardises several types of information transmitted, including time, station identification and programme information.Radio Broadcast Data...
environment, the TP signal is equivalent to this basic function.
The basic method implemented on an analog receiver would be a switch usually marked SDK or VF. Radios that used the "classic" mechanical push-button preset system would have one of these buttons set aside as the VF switch. If this switch was on, the radio would mute unless it was tuned in to a station that transmitted this signal.
If the radio was a digitally-tuned receiver, this switch usually engaged an "ARI-seek" mode which had the radio seek for any ARI station if it was out of range of the currently-tuned ARI station.
DK signal
This function, which is superseded by the RDS TA function, was tied in with the broadcasting studio and would be triggered whenever the traffic-announcement jingle was played. A 125 Hz tone would be modulated on the 57 kHz ARI subcarrier tone while this was happening.A radio that used a "DK" switch, often part of the "SDK" or "VF" switch, was placed in to "traffic-priority" mode. It would pick up on this signal and come out of a muted state or cut over a tape or CD that was playing and play the announcement at a fixed volume level.
There was the ability to switch off such announcements on these sets if the driver found a particular announcement irrelevant or it ran on for too long, but it was not easily explained to people new to the system. This was also confusing because a lot of cheaper implementations used a mechanical toggle switch to engage / disengage ARI mode and it was hard to simply use this switch simply to reset the system.
BK signal
This function was based on one of six tones that was in this same subcarrier and was reserved for high-end car radios. These were referred to as A, B, C, D, E and F; and they worked as a crude way of machine-based geocoding for Germany's broadcast areas.The set would indicate the current zone that it was in rather than using an "SK" indicator whenever it was on an ARI station. As well, the user could control ARI search behavior based on the current zone, a user-nominated zone such as the neighboring zone or any ARI station in any zone.
Attempts to deploy ARI in the U.S.
Blaupunkt even made attempts to roll it out in to the US market since 1982 by gaining support from selected FM broadcasters in the big US cities, but it did not catch on. As well, they had been the only company to put ARI-equipped sets on the U.S. marketplace, as a way of differentiating their product from others. There was talk of encouraging other manufacturers to sell ARI-equipped car radios to the U.S., but there was no action even though other manufacturers would roll out ARI-equipped radios to Germany.Attempts to deploy ARI in Canada
ARI was introduced into Canada around the same time as the U.S., in Toronto. CHFICHFI-FM
CHFI-FM is a Canadian radio station, which broadcasts an adult contemporary format at 98.1 on the FM dial in Toronto, Ontario. Like most Toronto radio and TV channels, it broadcasts atop the CN Tower with and ERP of 44 kW and has a sizeable amount of American listeners...
was the station designated for such broadcasts, and ads for new Blaupunkt car stereos announced it, but just like in the U.S., ARI did not seem to catch on.
External links
- http://gauss.ffii.org/PatentView/EP419776 Pioneer circuitry improvement for traffic-priority in car radios