Ericsson F251m Manual de usuario descargar pdf (Pagina 15)

3. ELECTRICAL DESCRIPTION

LZT 123 7359 R1B

Audio signal descriptions are listed below:

MICP and MICN are balanced differential microphone input signals.

These inputs are compatible with an electret microphone.

BEARP and BEARN are the speaker output signals. These are

differential-mode outputs. The electrical characteristics are given in the

table below.

The following table shows the ear piece impedances that can be

connected to BEARP and BEARN.

16 independent audio filters (8 transmit and 8 receive) determine the

frequency/gain response characteristics of the audio interface. The gain

characteristics of each of the Tx and Rx filters can be customised using

AT commands to optimise and match the performance of the audio

interface to a particular handset or audio sub-system.

The allowable range of the gain parameter for each RX and TX DSP

filter is -11 to +9dB.

The factory default settings for the DSP filters provide optimised

performance for the recommenced handset accessory.

Pin Signal Dir Description

1 MICN I Microphone negative input

2 BEARN O Earpiece negative output

3 BEARP O Earpiece positive output

4 MICP I Microphone positive input

Parameter Limit

Output level (differential) ≥4.0V

Output level (dynamic load = 32Ω) ≥2.8V

Distortion at 1kHz and maximum output level ≤5%

Offset, BEARP to BEARN ±30mV

Ear-piece mute-switch attenuation ≥40dB

Ear piece model Impedance Tolerance

Dynamic ear piece [32Ω + 800µH] // 100pF ±20%

Dynamic ear piece [150Ω + 800µH] // 100pF ±20%

Piezo ear piece 1kΩ + 60nF ±20%

1 2 ... 10 11 12 13 14 15 16 17 18 19 20 ... 29 30

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Ericsson F251m Manual de usuario Pagina 15