Siemens SXG 75 Service Repair Documentation page 30

Signal
WCDMA Power Detector
HDET1
WCDMA PA
PA_ON0
GSM Tx VCO
TX_VCO_1_EN_N
TX_VCO_0_EN_N
GSM PA
GSM_PA_EN
GSM_PA_BAND
GSM_PA_RAMP
RTR6250 GPS Rx IQ Interface
RX1_I_M
RX1_I_P
RX1_Q_M
RX1_Q_P
RTR6250 GSM / WCDMA Tx IQ Interface
TX_I_M
TX_I_P
TX_Q_M
TX_Q_P
TX_IREF
RTR6250 Tx system controls
TX_ON
TX_AGC_ADJ
Technical Documentation
TD_Repair_L3_SXG75_R1.0.pdf
Function
Voltage proportional to TX power of WCDMA signal. Fed to HKAIN2 input
to MSM6250 ADC multiplexer.
Logic control to enable PA.. Turns the PA on and off as required to
support UMTS operation while consuming minimum DC current.
Logic control to set VCO operating band. TX_VCO_0_EN_N = 0,
TX_VCO_1_EN_N =1 > high band
TX_VCO_0_EN_N =1, TX_VCO_1_EN_N =0 > low band
Logic control to enable GSM PA.
Steps the PA gain and bias, greatly reducing DC current consumption
under typical operating conditions.
Logic control to set GSM PA operating band.
DAC voltage to set GSM PA power. A control line that is filtered within the
automatic power control circuits to smoothly ramp the PA on prior to
transmit energy being applied.
Received GPS IQ signals. The IQ signals are concerted to digital by
analog-to-digital converter (ADC) circuit within the MSM6250 IC.
Transmit IQ signals. The transmit baseband signals are
generated by digital-to-analog converter (DAC) circuit within the
MSM6250 IC.
Transmit GPS IQ signals. The IQ signals are concerted to digital by
analog-to-digital converter (ADC) circuit within the MSM6250 IC.
DAC reference voltage provided by the RTR6250. Used to improve TX IQ
DAC signal quality.
Logic control. Used to control the RTR6250 operating mode.
A pulse-density modulated digital signal from the MSM6250. It is filtered
by R902/C900 to form an analogue control voltage. This voltage is used to
set the WCDMA transmitter power.
Company Confidential
2006©BenQ
Release 1.0
01/2006
Page 30 of 73