5
the voice coding/decoding unit is to conduct compressing and coding operations
over 64K voice and digital code traffics like EVRC codes, to let them be suitable
for being transmitted in wireless environment. The baseband signal processing unit
mainly includes functions like baseband modulation/demodulation and channel
coding/decoding. It also includes the CPU system through which protocol software
runs, as well as FLASH for storing software and SRAM for running software.
The power and power-management modules fulfils functions like system power
supply and power management.
The radio frequency sub-system includes radio frequency processing unit and
antenna feeder system. Radio frequency signal processing functions cover
functions of modulating and demodulating baseband signals, power amplifying,
and frequency modifying. The primary function is to convert baseband signals into
radio frequency signals proper for wireless transmission and the reverse function.
The corresponding proper interface is the Um interface of CDMA2000 1x.
PIPU board interface module mainly provides power, PCM interface, UART
interface, USB interface and R-UIM interface. It is a 72PIN pad
1.2.2 PIPU Board Hardware Structure
Keypad
Hook
4-wire interface
R-UIM interface
primary power
protection module
power switch
second-time
power switchover
startup/
shutdown
control
serial
port
protection
antenna
interface
antenna
LCD module
LCD BUS
handle
speaker
microphone
audio
channel 1
audio
channel 2
charging circuit
battery
72Pin TCPU module pad
second-time power
second-time power
LCD interface
KPAD interface
charging control
DB9
Figure1-3
PIPU board hardware structure
A shown in Figure 1-3, the PIPU board mainly includes the following circuit
modules, user sub-system, power supply and power management module.
The user sub-system includes serial port protection module, R_UIM card interface,
audio channels 1 and 2, environmental variable monitoring module, etc.