IV - Installing the RDS2 in your Broadcast System
After the BW RDS2 encoder unit has been programmed it can be added to an active broadcast
system. When including the RDS2 into a broadcast system you must consider two important
points:
1.
Pilot Synchronisation
2.
Equipment configuration
4.1 Pilot Synchronisation
The RDS signal operates at 57kHz which is a multiple of the 19kHz pilot tone used for
transmission of stereo FM signals. If the 57kHz carrier used for the RDS signal is ‘In-
Phase’ with the 19kHz pilot tone the combined signal will have a lower maximum
level than if the signals are out of phase. This means a synchronised RDS encoder
will contribute less to the overall deviation of an FM signal allowing a high deviation
percentage from the audio signal.
The RDS2 is capable of synchronising to a 19kHz reference in one of two ways:
i.
19kHz reference input
– RDS2 will synchronise to a 19kHz
signal applied to the reference input. This signal can be either
square or sine wave from 1V to 10V P-P.
ii.
Pilot lock on MPX input
– The RDS2 will synchronise to the
19kHz pilot in a stereo multiplex signal applied to the MPX
input.
If no 19kHz signal is present in the 19kHz reference port or in the MPX input, the
RDS signal will be ‘free-running’. This allows the RDS2 to operate with mono
broadcasts.
4.2 Equipment Configuration
The RDS2 can be installed in a broadcast system in a
Loop-Through
configuration or
as a separate subcarrier (SCA) signal generator that can inject the RDS signal through
the input on another piece of equipment in the audio chain.
4.2.4 Loop-Through Configuration
In ‘Loop-Through’ configuration the stereo multiplex (MPX) signal normally fed into
an exciter is input into the ‘MPX’ input of the RDS2. The RDS2 will synchronise the
generated RDS signal to the 19kHz pilot present on the stereo input and multiplex the
resulting 57kHz RDS signal with the stereo signal. The level of the input stereo signal
will remain unchanged.
The combined RDS/Stereo multiplex signal is then input to the exciter of the
transmitter.
The RDS2 has been designed with relays on the MPX input such that in the case of
power failure the relays will switch over and the stereo signal will simply pass through
the unit.
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Summary of Contents for rds2
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