AVT MAGIC TBR, Hardware And Software Manual

Page: 11 / 67

INTRODUCTION
11
Voice Break-In Function
During the repeater operation the received Ensemble is analysed permanently to
always have the current Multiplex Configuration Information (MCI) available – even
after reconfigurations.
In case of a necessary voice break-in all DAB and DAB+ Audio sub channels are
automatically replaced by the emergency signal. The signal will be completely
remodulated (see Figure 4).
The encoder bitrate of the break-in signal depends on the currently lowest bitrate
of all Audio sub-channels in an ensemble.
The complete Multiplex is fully replicated and replaced frame-synchronously. From
the view of a DAB Radio a continuous signal is received in terms of data rate,
sampling frequency, error protection, but also CIF Counter, time etc.
In this way it is guaranteed that the DAB receiver does not lose the synchronisation
or even re-scans the DAB band.
In parallel, PAD data can be transmitted as Slideshow and/or as Dynamic Label so
that the respective information can also be presented visually.
If a car driver listens to another medium (e.g. CD), the receiver can be switched
automatically to DAB radio via an appropriate alarm signalling (if the receiver
supports this feature).
The break-in trigger is in general realised via a TTL input signal, an IP SNMP
command or optionally via a remote VoIP telephone call.
Beside live break-in, multiple predefined break-in signals – together with a Dynamic
Label (DL) and a Slide Show (SLS) – can be stored in the system.
Figure 4: Remodulator Mode