Sierra Wireless AirPrime SL8080, Hardware Integration Manual, Page: 16 / 22

AirPrime SL8080 Series Hardware Integration Guide
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Audio function codec responsibilities
The responsibilities of the module codec and host codec for special functions are
detailed in
Table 4-3 on page 16.
Table 4-3: Codecs responsible for special functions
Function
Responsible codec
Module Host
FIR filtering Tx and Rx paths

-
Noise
suppression
Required due to high sensitivity and gain in Tx path

-
Echo
cancellation
Different for each audio path and environment (handset, headset, car kit,
speakerphone)

-
High pass
filtering/slope
filtering functions
Required per phone acoustic requirements

-
AGC (Automatic
Gain Control)
Normalizes audio volumes in varying acoustic environments

-
DTMF tones Generation and detection of DTMF tones is required in both directions of the phone
interface

-
Comfort noise Low level noise injected into Rx path for user ‘connection’ experience

-
Simple ringers Digital and analog tones, melody ringers, MIDI with limited memory storage

-
Voice memo Performed by host if significant memory storage is required -

Polyphonic
ringtones
Host ovten supports WAV, MIDI formats with significant memory storage -

Path switching Turn on audio path depending on user interface selection, or headset detection -

Path mixing Required for voice memo recording and playback via multiple audio paths -

Transducer
interfaces
Host provides acoustic drivers.
Must occur outside of path switching and mixing
-

Adjustable gain/
volume settings
Based on user interface selections
 
DTMF/ringer
tone generation
 