Panasonic EB-X400 Service Manual

Also see for EB-X400: Operating instructions Operating instructions

Contents

– 5-1 –5.1. RF Overview5.1.1. RF Block Diagram5.1.2. Functional DescriptionThe dual-band receiver comprises mainly an RF transceiver IC and and Front-End module.The transceiver (U101) contains a direct conversion receiver with DC offset calibration circuitry and the following circuit blocks:8 EGSM900 and DCS1800 internal LNAs.8 EGSM900 and DCS1800 down-conversion mixers/demodulators.8 Channel filtering and base-band signal variable gain amplifiers with programmable gain control function.The Antenna Switch Module S101 is a dual-band antenna switch module. Two external SAW filters EL201 and FL202 forEGSM900 and DCS1800 are used to improve the isolation between 900MHz and 1800MHz.The impedance of these two filters' output is 150 Ω balanced.EGSM900/DCS1800The input receiving signals into the LNAs coming from the SAWs provide out-band reflection.However, the receiver is a direct conversion type, there is no need to concern about the image frequency blocking problem.Figure 5.1. RF Block Diagram5. TECHNICAL DESCRIPTIONU301TCXO moduleMAA****A26 MHzI/IBQ/QB13M_BBPALEVELAFCEGSM900925 - 960 MHzEGSM900880 - 915 MHzDCS18001710 - 1785 MHzU103PA ModuleRF3140DCS18001805 - 1880 MHzS101Antenna Switch moduleFL102Tx SAW EGSMEFCH897MMTE7FL202Rx SAW Filter EGSMB7820FL201Rx SAW Filter DCSB7821U101Transceiver ICDC offset Compensation1/4++U102Tx Limiter ICPMB2256V V1.1TXONCLK/DA/ENBAND_SELRF SynthPLLON3420 - 3980 MHzVC1VC2TXON_PAAM_TRIGTEMPπ/21/4π/21/2π/21/2π/2