Figure 14: Speaker Differential Connection; Figure 15: Speaker Single-Ended Connection; This Document Is The Sole And Exclusive Property Of Wavecom. Not To Be Distributed Or Divulged Without Prior Written; Agreement - Wavecom Integra M2106+ Product Specification

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Table Of Contents

Table of Contents

3.9.2.1

Common Speaker Output Characteristics

The connection can be differential or single-ended but the use of a differential connection to reject common

mode noise and TDMA noise is strongly recommended. Moreover in single-ended mode, ½ of the power is

lost. When using a single-ended connection, ensure to have a good ground plane, good filtering as well as

shielding, in order to avoid any disturbance on the audio path.

Both SPK1 and SPK2 speaker outputs are push-pull amplifiers and can be loaded down to 32 Ω and up to

1 nF. The impedance of the speaker amplifier output in differential mode is: R ≤ 1 Ω±10 %.

These outputs are differential and the output power can be adjusted in steps of 2 dB (see details in Table 3:

Speaker gain vs Max output voltage). The output can be directly connected to a speaker.

In case of a single-ended connection, only half of the output power is available when compared to a

differential connection.

Sp ea ker

C1 = from 100 nF to 47 µF as per the speaker characteristics.

C2=C1

R1 = Speaker impedance

Nevertheless, in a 32 Ω speaker case, it is possible to use a cheaper and smaller solution: R1=82 Ω and

C2=4.7 µF ceramic.

The gain in the speaker outputs are internally adjusted and can be tuned by using an AT command (refer to

the AT commands documentation [7] for details).

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This document is the sole and exclusive property of Wavecom. Not to be distributed or divulged without prior written

agreement.

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