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3. Technical brief
GD510 Operational Description Revision A
LG Electronics 47/113 LGE Property
Figure 25 RF transceiver PMB6272 SMARTi-PM schematic
3.17. Receiver part
Figure 26 Receiver part block diagram
The constant gain direct conversion receiver contains all active circuits for a complete receiver chain for
GSM/GPRS/EDGE (see Figure 39). The GSM850/900/DCS1800/ PCS1900 LNAs with balanced inputs
are fully integrated. No inter-stage filtering is needed. The orthogonal LO signals are generated by a
divider-by-four for GSM850/900 band and a divider-by-two for the DCS1800/PCS1900 band. Down
conversion to baseband domain is performed by low/high band quadrature direct down conversion
mixers. The baseband chain contains a LNB (low noise buffer), channel filter, output buffer and
DC-offset compensation. The 3rd order low pass filter is fully integrated and provides sufficient
suppression of blocking signals as well as adjacent channel interferers and avoids anti-aliasing through
the baseband ADC. The receive path is fully differential to suppress on-chip interferences. Several gain
steps are implemented to cope with the dynamic range of the input signals. Depending on the baseband
ADC dynamic range, single- or multiple gain step switching schemes are applicable. Furthermore an
automatic DC-offset compensation can be used (depending on the gain setting) to reduce the DC-offset
at baseband-output. A programmable gain correction can be applied to correct for front end- and
receiver gain tolerances.
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General
Weight and Dimensions
