AEV STARGATE
Futurcom Srl via della Tecnica 35, 40050 Argelato Bologna ITALY
8
minimize the distance between the two and thus reduce any distortion that could be
introduced by the cable.
The buf fered outputs of STARGATE can drive cable lengths of upto 100 m before any
appreciable distortion occurs to the MPX signal.
To guarantee the best transmission quality, all equipment used, should be carefully aligned
and capable of satisfying the appropriate requirements for bandwith, distorsion, signal path
delay and gain stability.
This equipment should be calibrated at regular intervals; the signal source should be lownoise,
have as flat a frequency response as possible from 30 ÷ 15,000 Hz and have a low
content of non-linear distortion.
Overview of the RDS service
There is a growing, global interest, both on the part of industry, as well as broadcasters, in
information systems which utilize a data channel inserted into radiophonic transmissions.
The interest in these new systems has been stimulated by the continuing evolution of radio
receiver technology which, with the introduction of LSI (large scale integration) circuitry and
the microprocessor, has allowed operation to be simplified and new possibilities to be offered.
Many of these new possibilities have been developed for FM (frequency modulation) radio
where, thanks to the bandwidth available, it is possible to insert an additional data channel
onto the subcarrier, whilst maintaining compatibility with the stereophonic transmission and
remaining completely inaudible.
By transmitting channel and program identification codes on the additional data channel, it is
possible to simplify the manual tuning of receivers and even make it fully automatic. This is of
particular benefit with today’s large and continuously growing number of FM radio stations. It
is also possible to receive up-to-date traffic news and offer other interesting features.
In the future, when radios will be fitted with voice synthesizers, it will be possible to transmit
traffic news (or other information) on the additional data channel as well as on the regular
program, as happens now, which will continue to be received uninterrupted and independently
of the data channel.
- RDS - radiodata
This system for the transmission of additional information on mono and stereo VHF (87.5-
107.5MHz), represents the most technically advanced and, for the huge range of possible
applications, the only that has any real chance of being adopted on a global basis.
It fulfils the various requirements needed by systems for the transmission of additional data on
radio programs, namely:
COMPATI BI LI TY WI TH THE MAI N PROGRAM
,
MONO AND STEREO
;
ABSENCE OF I NTERFERENCE ON ADJACENT
FM
CHANNELS
;
POTENTI ALLY BETTER COVERAGE AREA COMPARED TO MONO TRANSMI SSI ONS
COMPATI BLE WI TH OTHER I DENTI FI CATI ON SYSTEMS
,
ALREADY I N SERVI CE
.
Radiodata is the fruit of work undertaken by a specialized UER group, based on five proposals
formulated by Sweden, The Netherlands, Great Britain, Finland and France.
The superiority of this system results mainly from its protection from transmission errors,
crucial for in-car reception, high speed to synchronize the data groups, from its high data rate,
its potential for new applications and flexibility of use.
The spectrum of a multiplex, stereophonic signal, containing data is shown in fig.1.
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