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5.2. Baseband Overview
The Baseband circuits of the phone are required to perform the following functions:
8
Equalization
8
Channel coding / decoding
8
Speech coding / decoding
8
Data Encryption
8
Layer 1, 2 and 3 software tasks
8
Man Machine interface (MMI)
8
System Interface
8
SIM Interface and Management
8
Audio and Tone Generation
8
Power supply and battery management
8
RF power control
8
Synchronization
8
Real time clock
GSM Processor
(AD6525)
Keyboard
R.F.
Block
BBCLK
Vibrator
Memory
Flash/SRAM
(64MB / 16MB)
ADC/DAC
VoiceBand
&
BaseBand
Codec.
(AD6521)
Power
Management
(ADP6522)
RTC
Crystal
RTC
Battery
LCD Module
Backlight
LED
MIC
Speaker
SIM
Socket
Keypad Data bus
CLKIN
OSC
32.768kHz
Data Bus
Address Bus
LCD Control Bus
A,V,B
serial Port
RF Control Bus
GPIO12
GPO22
EXTPWR
USC Data Bus
VBAT
SIM interface
VCC
Li-Ion
Battery
VCORE
VBAT
VANA
VANA
VANA
VCORE
VCORE
VBAT
LCD_PWR
TX IQ
RX IQ
Control Signal
VTCXO
VTCXO
VMEM
VRTC
VRTC
Handfree input
HANDFREE IN
GPIO6
LDO 3.0V
Receiver
VMEM
VMEM
SIMVCC
VSIM
Power
Jack
OverVoltage
Protect Circuit
Charging
Circuit
P MOSFET
VMEM
VRTC
SIMVCC
Buffer
VTCXO
13MHz_BB
Meledy IC
Control /Data
Interface
VOUTNOR P/N
YMU_AVCC
Phone
Jack
VOUTAUX P
Buzzer(L_SPK Mode)
VINNOR P/N
VINAUX P/N
HPOUT
TX/RX
BACKLIGHT
Charging control interface
LDO 3.0V
V_LED
White LED
DRV 4.5V
V_LED
Analog
Switch
PJ_FUNC_SEL
TX/RX
Audio
GPIO 13
PJ_FUNC_SEL
Figure 5.5. Baseband Block Diagram
The EB-G50 Baseband is built around a GSM chipset developed by Advanced Device. One chip (AD6525) carries out
signal processing with DSP and CPU, and the other chip (AD6521) provides the analogue interface.
The highly integrated nature of the chips means that each contains a large number of functions.
5.2.1. Introduction