LG KU250 Service Manual - Page 31
UMTS Rx RF filter FL103 : EFCH2140TDE1
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3. TECHNICAL BRIEF 3.5.7 UMTS Rx RF filter (FL103 : EFCH2140TDE1) • Frequency range : 2110 ~ 2170MHz An RF filter is located between the UMTS LNA and mixer. Insertion loss is important, but not as critical as losses before the LNA. The most important parameters of this component include: • Out-of-band rejection or attenuation levels, usually specified to meet these conditions: - FFar out-of-band signals - ranging from DC up to the first band of particular concern and from the last band of particular concern to beyond three times the highest passband frequency. - Tx-band leakage - the transmitter channel power, although attenuated by the duplexer, still presents a cross-modulation threat in combination with Rx-band jammers. The RF filter must provide rejection of this Tx-band leakage. - Other frequencies of particular concern . bands known to include other wireless transmitters that may deliver significant power levels to the receiver input. Table 1.3 WCDMA Rx SAW Filter Specification - 32 -