User's Manual

Audio Interface
Rev 1.12.4 Oct.09 Proprietary and Confidential 29
In the event of a discrepancy in values between this guide and the Product Specification Document (PSD), the PSD takes precedence.
Note: Data mixing is not supported. If mixing of voice signal is
required, it must be done by the host processor.
Figure 4-3: MC8775V /MC8790V / MC8791V / MC8792V / MC8795V Audio system block
Modes of operation
Thesemodulessupportsixoperationalmodes:headset,
handset,carkit,speakerphone,AUX
1
,andTTY—endproducts
canuseanycombinationofthesemodes.
Thehostdevicemustusehost‐modemmessagingtotellthe
modulewhichmodetouseforeachcall.
Sidetone support
Thesidetonepathmixesthe near‐endtransmitvoicetothe
near‐endreceive.Thisgivesthenear‐endusersomefeedback
thatindicatesthatthe callisupandthattheaudiosystemis
functioning.
ThesidetonepathcanbeenabledineitherthePDAcodecor
theMiniCard
modem—eachpathisequallyvalid.Itshould
notbeaddedtobothdevices,andforspeakerphoneorcarkit
applications,bothsidetonepathsshouldbedisabled.
Decoder
RX DAC
EncoderTX ADC
HPF &
Slope
HPF
Echo Cancellation
NS &
AAGC
Tx FIR
Rx FIR
13K CELP/
EVRC
Decoder
AAGC
13 bit A/D
13 bit D/A
CodecRxGain
RX_HPF_DIS_N
CodecSTGain
CodecTxGain
TX_HPF_DIS_N
TX_SLOPE_FILT_DIS_N
MIC_AMP1_GAIN
-6dB to +49.5dB
in 1.5dB steps
nsSwitch TxPCMFilt
TxVolume
RxVolume
RxPCMFilt
AMP_SEL
001 010 100
35mW @ +3dBm0
RF Filter
33n
22p
PCM I/F
+12dB
-25dB
-84dB
+12dB
-3dB
-84dB
+12dB
0dB
-81dB
+12dB
-48dB
-96dB
+12dB
0dB
-84dB
57.3mVrms
@ 0dBm0
SPK_P
SPK_N
MIC_P
MIC_N
13K CELP/
EVRC
Encoder
DTMF
Encoder
DTMF Rx Gain
DTMF Tx Gain
DTMF
Decoder
Audio In
Audio Out
RF
Interface
PCM Audio interface
1. (MC5727V/MC5728Vmodulesarepreconfiguredfor
HAC[HearingAidCompatibility]).