User's Manual

GE866-DUAL Hardware User Guide
1VV0301051 Rev. 2 – 2014-04-07 7
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Reserved. Page 49 of 82
Mod. 0805 2011-07 Rev.2
TIP:
In order to get the maximum audio level at a given output
voltage level (dBspl/Vrms), the following breaking through
procedure can be used. Have the loudspeaker as close as you
can to the listener (this simplify also the echo cancelling);
choose the loudspeaker with the higher sensitivity (dBspl per
W); choose loudspeakers with the impedance close to the limit
(ex: 16 or 8 Ohm), in order to feed more power inside the
transducer (it increases the W/Vrms ratio). If this were not
enough, an external amplifier should be used.
WARNING:
This The audio output hardware of the GE866-QUAD is based on a
Class-D amplifier so any singled-end output configuration MUST
NOT BE USED, otherwise the presence of GSM buzzing and low
level audio performance will result.
L-C filtering for LOW impedance load.
EAR+
EAR
-
TELIT MODULE
-
+
OUTPUT
DAC
GND