LEXI-R422 - System integration manual
UBX-23007449 - R02
System description
Page 8 of 108
C1-Public
1.2
Architecture
summarizes the internal architecture of LEXI-R422 modules.
V_INT
ANT
VCC (Supply)
USB
I2C
SIM card detection
SIM
UARTs
PWR_CTRL
Antenna tuner
Antenna detection
PAs
RF
transceiver
19.2 MHz
Power
Management
BaseBand
Processor
GPIOs
Filters
Filters
Memory
Switch
Figure 1: LEXI-R422
modules’ simplified block diagram
Below is a detailed description of LEXI-R422 modules sections shown in figure above.
Cellular RF section
The cellular RF section is composed of the following main elements:
•
RF switch connecting the antenna port (
ANT
) to the suitable RF Tx / Rx paths
•
Power Amplifiers (PA) amplifying the Tx signal modulated and pre-amplified by the RF transceiver
•
RF filters along the Tx and Rx signal paths providing RF filtering
•
RF transceiver, performing modulation, up-conversion and pre-amplification of baseband signals
for transmission, and performing down-conversion and demodulation of RF signals for reception
•
19.2 MHz crystal oscillator generating the reference clock signal for the RF transceiver and the
baseband system, when the related system is in active mode or connected mode
Baseband and power management section
The baseband and power management section, is composed of the following main elements:
•
On-chip modem processor, vector signal processor, with dedicated hardware assistance for signal
processing and system timing
•
On-chip modem processor, with interfaces control functions
•
On-chip voltage regulators to derive all the internal or external (
V_SIM
,
V_INT
) supply voltages
from the module supply input
VCC
•
Dedicated flash memory IC
•
Calibrated low frequency RC oscillator to provide the clock reference in the low power idle mode,
which can be enabled using the +UPSV AT command, and in the PSM / eDRX deep-sleep mode,
which can be enabled using the +CPSMS / +CEDRXS / +UPSMVER AT commands
