3. TECHNICAL BRIEF
- 37 -
LGE Internal Use Only
Copyright © 01 LG Electronics. Inc. All right reserved.
Only for training and service purposes
- 37 -
LGE Internal Use Only
Copyright © 011 LG Electronics. Inc. All right reserved.
Only for training and service purposes
3.5.2 FUNCTIONAL DESCRIPTION
3. TECHNICAL BRIEF
3.5.2.1 Receiver
The X-GOLD™215 dual-band receiver is based on a Direct Conversion Receiver (DCR) architecture. Input
impedance of the LNAs is optimized to achieve a matching without (external) high quality inductors. By use of
frequency dividers (by 2/4) the LO frequency is derived from the RF frequency synthesizer.
The receive path is fully differential to suppress the on-chip interferences and reduce DC-offsets. The analog
p
y
pp
p
g
chain of the receiver contains two LNAs (low/high band), a quadrature mixer followed by an analog baseband
filter and 14-bit continuous-time delta-sigma analog-to-digital converter. The filtered and digitized signal is fed
into the digital signal processing chain, which provides decimation, DC offset removal and programmable gain
control.
Figure. 3.5.2 RECEIVER CHAIN BLOCK DIAGRAM
ͽͶ͑ͺΟΥΖΣΟΒΝ͑ΆΤΖ͑ΟΝΪ
Z_VX[^
GSM
850/900
GSM
1800/1900
RX1
RX1X
RX
RXX
LNA_GAIN
DCO
RXBBFG[:0]
DGAIN[5:0]
RXTXDA
RXTXEN
DigRF
RX