Specifications

AirPrime Embedded Module Hardware Integration Guide
54 Proprietary and Confidential 2130114
Audio function partitioning
The following phone-oriented functions are usually under module control:
• FIR filters—Transmit and receive paths
• Noise suppression—Required due to high sensitivity and gain in transmit
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 receiver path for user
"connection" experience
• Simple ringers—Digital and analog tones, melody ringers, MIDI with limited
memory storage
The following functions are typically performed in the host codec:
• Voice Memo—Performed by the host if significant memory storage is
required
• Polyphonic ringtone—Host often supports WAV, MIDI formats with significant
memory storage
• Audio path switching—Turn on audio path depending on user interface
selection, or headset detection
• Audio path mixing—Required for voice memo recording and playback via
multiple audio paths
• Transducer interface—Host provides acoustic drivers, must occur outside of
path switching and mixing
These functions can be performed in either the host or module codec, depending
on balance of component selection and engineering resources:
• Volume settings—Adjustable gain settings based on user interface selections
• Sidetone—Careful placement of sidetone gain control is required to prevent
the need to adjust sidetone gain with varying volume settings
Table 4-6: PCM digital audio signal interface
Signal Pin # Type Direction Description
PCM_CLK 45 Digital Output PCM clock
PCM_DIN 47 Digital Input (internal pull-down) PCM data in
PCM_DOUT 49 Digital Output PCM data out
PCM_SYNC 51 Digital Input (internal pull-down) PCM sync