LG -T370 Service Manual page 52

DSP
DSP bus
DSP interrupt
unit
FPI bus
Figure 3.12.2 Overview of Clocking and Interfaces of Audio Front End
The audio front-end of X-GOLD™215 has the following major operation modes:
• Power-down: All analog parts are in power down and all clocks of the digital part are switched off.
• Audio mode: Digital decimation/interpolation filters are connected to the interface buffers and the analog
part is enabled.
These major modes can be modified by certain control register settings.
• Due to the new gain settings in the TX path, the maximum input voltage is limited to 0.8 Vpp.
• In both voiceband paths, the value range for voice samples is confined to 97.5%, i.e. to [-31948, 31947] or
[8334H, 7CCBH] in X-GOLD™215.
• On the TX path, 83% "1"s on the VTPDM line correspond to a 16-bit value of 7CCBH and 17% "1"s correspond
to a 16-bit value of 8334H at the digital filter output. Thus the usable range is 66%. This range can be scaled to
100% by Firmware. y
• The high-pass functions of the voiceband filters have to be implemented in firmware on TEAKLite®.
LGE Internal Use Only
RX
DSP bus
Buffer
Cintrd
and sidus
regsiars
TX
Buffer
digital
filters
ASMD
comb
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3. TECHNICAL BRIEF
3. TECHNICAL BRIEF
DACr
DACI
ADC
Only for training and service purposes