User's Manual

GE866-DUAL Hardware User Guide

1VV0301051 Rev. 2 – 2014-04-07

Reproduction forbidden without written authorization from Telit Communications S.p.A. - All Rights

Reserved. Page 48 of 82

Mod. 0805 2011-07 Rev.2

10. Audio Section Overview

10.1. MIC Connection

The Base Band Chip of the GE866-QUAD provides one input for

audio to be transmitted (Uplink).

10.2. EAR Connection

The audio output of the GE866-QUAD is balanced, this is

helpful to double the level and to reject common mode (click

and pop are common mode and therefore rejected); furthermore

the output stage is class-D, so it can manage directly a

loudspeaker with electrical impedance of at least 8Ohm. This

stage is powered by switching from Vbatt to gnd at a frequency

ranging from 0.6 to 2MHz, so it has a good efficiency and thus

a big power budget 0.7W; being a class-D architecture, please

use some caution (see the NOTE below).

NOTE:

When the loudspeaker is connected with a long cable, an L-C

filter is recommended.

When the EAR+/- are feeding some electronic circuitry, an R-C

filter is recommended.

EAR+

EAR-

TELIT MODU

OUTPUT

DAC