EXC-GT – FM super-compact transmitter series
User’s manual – Page 20 of 98
7
A
UDIO OPERATING MODES AND ASSOCIATED
BF
CONNECTIONS
This section describes how to select the various available operating modes, and how to make audio connections according to your
requirements.
The transmitter is equipped with numerous characteristics specific to high-fidelity systems; as such, it should be connected to
modulating signals with the same care as a Hi-Fi system, avoiding ground loops as much as possible. Under these conditions, you
will obtain optimal performance.
According to the operating mode and type of modulation source available, you can connect to the modulation inputs in various ways:
Monophonic transmission from an audio signal, via the main mono channel
Monophonic transmission from a stereophonic audio signal, using the internal stereo encoder
Stereophonic transmission from a stereophonic audio signal, using the internal stereo encoder
Monophonic or stereophonic transmission from an external encoder or radio link receiver.
The device is also able to transmit an auxiliary signal (RDS or SCA), connected to the rear AUX input as described below.
7.1
Mono transmission from a mono signal
1) Connect
the
RIGHT
connector [22] to the monophonic audio signal. Connection to the
LEFT
input is not necessary.
2) Using
the
SETUP
menu, set the modulation mode to
Mono
(
2
section 10.3.f).
3)
Confirm or change preemphasis according to the local standard.
7.2
Mono transmission from a stereo signal
1) Connect
the
RIGHT
connector [22] to the right audio channel.
2) Connect
the
LEFT
connector [21] to the left audio channel.
3) Using
the
SETUP
menu, set the modulation mode to
Mono L+R
(
2
section 10.3.f).
4)
Confirm or change preemphasis according to the local standard.
7.3
Stereo transmission from a stereo signal using the internal stereo encoder
Follow the steps outlined in section 6.5.b, ensuring that
Stereo
is selected at step 3.
7.4
Monophonic or stereophonic transmission from a multiplex signal
If you wish to use a multiplex signal (MPX) originating, for example, from an external encoder or a radio link receiver, follow the
steps below:
1)
Connect the multiplex signal to the
MPX
connector [17]. The multiplex signal is already preemphasized; as such, using the
MPX input, the filtering and stereo encoding stages are skipped and the signal will not be further preemphasized.
2) Using
the
SETUP
menu, set the modulation mode to
Mpx
(
2
section 10.3.f).
Selecting the preemphasis according to the local standard (50 microseconds in Italy) is not required, as it is irrelevant in this
mode. However, it is recommended that this be done anyway.
If the length of the cable delivering the signal to the MPX connector is only a few meters long, a 50 Ohm (RG58) cable can be
used. If the distance is greater, a 75 Ohm (RG59) or 92 Ohm (RG62) cable should be used.
7.5
Connection to LEFT, RIGHT, or MPX modulation connectors
The EXC-GT Series supports both balanced and unbalanced audio signals according to the connection that is made in the three
LEFT
and
RIGHT
XLR connector contacts. The input impedance for these contacts is pre-set at the factory at 10 KOhm resistivity (5
KOhm for unbalanced connections), which can be decreased to 600 Ohm if necessary, as explained further ahead.
Normally, an XLR audio input with balanced connection is used for connection to the balanced output of a professional mixer.
Alternatively, an unbalanced connection can be used, and is useful for output connections on inexpensive devices, without a
perceptible degradation in the audio signal.
Alternatively to connection to the
LEFT
e
RIGHT
connectors, an externally created multiplex signal can be connected to the
MPX
connector. In this case, connection should not be made to the
LEFT
and
RIGHT
connectors.
