LG TU550 Service Manual page 137

6. BLOCK DIAGRAM
Main RF signal
GSM850 TX : GSM850 Tx RF signal
GSM850 RX : GSM850 Rx RF signal
GSM900 TX : GSM900 Tx RF signal
GSM900 RX : GSM900 Rx RF signal
DCS TX : DCS Tx RF signal
DCS RX : DCS Rx RF signal
PCS TX : PCS Tx RF signal
PCS RX : PCS Rx RF signal
UMTS 850 TX : UMTS 850 Tx RF signal
UMTS 850 RX : UMTS 850 Rx RF signal
UMTS 1900 TX : UMTS 1900 Tx RF signal
UMTS 1900 RX : UMTS 1900 Rx RF signal
TX_I/Q : I/Q for Tx of RF
RX_I/Q : I/Q for Rx of RF
Control signal(red)
ANT_SEL 0,1,2 : Ant Switch Module Mode Selection
(UMTS, GSM850/GSM900 Tx/Rx, DCS Tx/Rx, PCS Tx/Rx)
GSM PA_CTL signal
GSM_PA_BAND : DCS or PCS /GSM Mode Selection
GSM_PA_EN : Power Amp Gain Control Enable
GSM_PA_RAMP : Power Amp Gain Control
GSM/DCS_VCO_EN
GSM_VCO_EN : GSM band Tx VCO Enable
DCS_VCO_EN : DCS band Tx VCO Enable
UMTS PA_CTL signal
PA_ON : UMTS Tx Power Amp Enable
TX_AGC_ADJ(VCONTROL) : UMTS Tx Power Amp Gain Control
W_VMODE_N : Switch to the Low Power mode
TRK_LO_ADJ : TCXO(19.2M) Control
UHF_VCO_BAND : UMTS(3G)/GSM(2G) VCO Band Selection of UHF VCO
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Only for training and service purposes