Transmitter Part - LG MG180C Service Manual

3.3 Transmitter Part

The Transmitter part contains the transmitter parts of Si4210-GM[U501], Power Amp Module[U501]
and Front End Module[FL500]. The transmit section of Si4210-GM[U502] consists of an I/Q base band
up_converter, an offset phase-locked loop(OPLL) and two output buffers that can drive external power
amplifiers(PA). The RF GMSK outputs from the transmit VCO are fed directly to the RF power
amplifiers. The peak output power and the profile of the transmitted burst are controlled by means of
incorporated pow er control circuits inside of PA and DAC output from the Base band Controller. The
PA outputs pass to the antenna connector via Front End Module.
FL500
Front End Module
DCS
PCS
GSM 850/
EGSM
D
D
I
I
P
P
GSM 850/
EGSM
DCS/ PCS
PA PA
RFOD
RFOG
1
1
2
2
ANT_SW1,ANT_SW2
Figure 3. RF Transmit Block
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3. H/W Circuit Description
PAM RF3166 (U501)
PA_BAND
IF PLL Si4210 (U502)
IF PLL
RF PLL
RF PLL
2
2
DET
DET
Baseband
Baseband
(TI)
(TI)
U100
U100
IOTA
IOTA
Q
+
+
U100
U100
Calypso-
Calypso-
I