LG U8290 Service Manual page 26

3. TECHNICAL BRIEF
The RFR6200 IC includes LO generation and distribution circuitry to reduce offchip component
requirements. The UMTS Rx LO source is created using an external UMTS Rx CH VCO that is closed-
loop controlled by the RTR6250 PLL2 via a discrete loop filter. The external UMTS_RX_VCO signal is
processed by the LO generation and distribution circuits to create the quadrature downconverter LO
signal. The LO signal applied at the mixer ports are at a frequency different than the VCO frequency.
This assures that the VCO frequency is different than the RF frequency, an important consideration for
Zero-IF processing. QUALCOMM.s Mobile Station Modem (MSM6250) device provides status and
control signaling, employing power reduction features (such as selective circuit power-down, gain
control, and bias control) to extend handset standby time.
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