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channel. Furthermore, the channel can also be selected with the
microphone. The received channel is shown on the display.
If the key
BEEP
is activated, pressing the
s
key is confirmed by
one
beep and pressing the
t
key is confirmed by
two
beeps.
Volume control (VOL)
The volume is set using the inner knob
VOL
of the double poten-
tiometer which is also used for switching on the radio set. When
the receive signal is lacking and the squelch function is deactivated,
the noise should be audible very well in FM modulation. In FM the
received speech signal is always a bit quiter than the noise without
signal. After having set the volume, the squelch function should
be activated.
Squelch/SQ
Each radio set and consequently the xm 5003 as well features
a function for noise suppression (squelch) suppressing the repro-
duction, if the signal is lacking or too weak. Use the
SQL/ASC
control to adjust the signal level at which the function is activated.
The
SQ/ASC
control is the outer knob of the double potentiometer.
By turning the knob to the left, the signal level is reduced, by turning
the knob to the right, the signal level is increased. With constantly
varying conditions of reception, as for example during mobile
operation, a frequent adjustment of this level can be necessary.
(A)utomatic (S)quelch (C)ontrol
The ASC function is a patented function elaborated by the President
Electronics SA France group. This function evaluates the so-called
signal-to-noise ratio (ratio between the useful signal and the inter-
fering signal). The useful signal is only forwarded to the loudspeaker,
if it is worth being received, i.e. it is almost free from noise. Thus,
a permanent readjustment, as for the squelch function depending
on the field strength, is not necessary. This is of benefit to a safe
participation in the street traffic when driving. The ASC function
can be used for AM and FM mode and is activated if the squelch
control is set to the leftmost position. Furthermore,
ASC
appears
on the display.
Type of modulation (AM/FM)
Using the channel configurations
d
and
EU
, you can use both
the type of modulation FM and the AM modulation. The decision,
which of both types of modulation is your preferred one, depends
on your radio contact partners and on your requirements. However,
please keep the compulsory registration for AM mode in mind
which applies in many countries!
Generally speaking, frequency-modulated signals (FM) are less
sensitive to interferences resulting from the ignition system etc.
than amplitude-modulated (AM) signals. If your loudspeaker emits
an unintelligible, distorted signal, you should try receiving the signal
using a different type of modulation.
For changing the type of modulation, actuate the key labeled
AM/FM
. The selected type of modulation
AM
or
FM
is indicated
on the display.
