User's Manual

CE910-DUAL Hardware User Guide
1vv0301010 Rev .0 – 2012-07-10
Reproduction forbidden without written authorization from Telit Communications S.p.A. - All Rights Reserved. Page 44 of 63
9.3. EAR connection
The audio output of the CE910-DUAL is balanced, this is helpful to double the level and to reject common
mode (click and pop are common mode and therefore rejected). These outputs can drive directly a small
loudspeaker with electrical impedance not lower than 32Ohm.
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
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.