Rf Interface - LG KG270 Service Manual
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3.9 RF Interface
VC1
VC2
C417
27p
CHANGE THIS DUAL SAW FILTER
E-GOLDvoice features a fully integrated constant-gain direct conversion receiver, i.e. there is no
interstage filter needed and the baseband level at the analogue IQinterface follows directly the RF
input level. Depending on the baseband ADC dynamic range, single- or multiple-step gain switching
schemes are possible.
An integrated, selfaligning, low-pass filter ensures the receivers to function under blocking and
reference interference conditions and avoids aliasing by baseband sampling. An automatic DC-offset
compensation is implemented and can be switched depending on the gain setting.
Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
C418
27p
Figure 3-9-1. ASM interface
2
3
5 10
O2_2
I2
4
6
O2_1
7
O1_2
8
O1_1
I1
1
9
FL401
B9308
PART_NO SFSB0001401
IN CASE OF GSM850/PCS1900
TO PART_NO SFSB0001301
Figure 3-9-2. SAW Filter interface
3. TECHNICAL BRIEF
FL400
9
IN
GSM1800_1900TX
GSM1800_1900RX
3
VC_GSM850_900TX
7
VC_GSM1800_1900TX
5
GND1
8
GND2
10
GND3
C419
3p
L403
18nH
C420
3p
C421
3p
L404
5.1nH
C422
3p
- 31 -
LMSP2PAA-575TEMP
1
6
2
GSM850_900TX
4
GSM850_900RX
GSM_RXN
GSM_RXP
DCS_RXN
DCS_RXP
LGE Internal Use Only
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