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Copyright © 2009 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only
4. RF Circuit Technical Brief
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2008 LG Electronics. Inc. All right reserved.
Only for training and service purposes
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4.3.3 Synthesizer
The receiver and the transmitter contain each a complete fractional-N RF synthesizer with fast locking.
The VCO’s run at 4 GHz and the RX and TX frequencies are obtained through division by two (bands I,
II, III and IV) or four (bands V and VI). The PLL loop filters are fully integrated. The reference
frequency has to be provided by an external clock.
The total VCO frequency range is divided in 256 subranges, in order to limit the VCO slope. Before the
settling process of the PLL starts, a successive approximation algorithm selects the most appropriate
subrange.
