After Sales
Technical Documentation
RAE/RAK–1N
Baseband
Page 2–32
Original, 08/96
AUDIO
Introduction
The AUDIO block contains an audio codec and a booster amplifier
together with some peripheral components. The codec contains
microphone and earpiece amplifiers and all the necessary switches for
routing. The codec is controlled by the MCU. The PCM data comes from
and goes to the DSP. The booster amplifier for the Personal Hands–Free
(PHF) is connected to one of the codec’s outputs. Physically the codec
resides in MCM2 while the other parts are assembled on the CMT
motherboard.
Technical specification
Table 34. External Signals and Connections, Inputs
Signal Name Signal description From
VA1 Analog supply voltage. Max 40 mA. PWRU
VA3 Analog supply voltage for the PHF power amplifier. Max 200
mA.
PWRU
PCMIN Received audio in PCM format DSPU
SYNC 8kHz codec frame sync ASIC
CODEC_CLK 512kHz codec main clock ASIC
PCMCDI Audio codec control data CTRLU
PCMCLK Clock for audio codec control data transfer CTRLU
XSELPCMC Audio codec chip select CTRLU
AMP_PWR PHF power amplifier control CTRLU
MICN, MICP Differential handportable microphone signal SIM Conn
EXTMIC External microphone signal B2B Conn
PHFMICN,
PHFMICP
Differential Personal Hands–Free microphone signal B2B Conn
Table 35. External Signals and Connections, Outputs
Signal Name Signal description To
PCMOUT Transmitted audio in PCM–format DSPU
PCMCDO Audio codec control data CTRLU
JCONN Junction box connected signal (multiplexed with EXTMIC) CTRLU
EARN, EARP Received audio to the earphone, differential signal SIMFLEX
Conn
EXTEAR Received audio to the external accessories B2B Conn
PHFEARN,
PHFEARP
Received audio to the Personal Hands–Free speaker,
differential signal
PHF Conn
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