SIGNAL CONVERSION CIRCUIT OF A MOBILE COMMUNICATION TERMINAL, CONCERNED WITH TRANSCEIVING TD-SCDMA, GSM, AND DCS-BASED SIGNALS

摘要

PURPOSE: A signal conversion circuit of a mobile communication terminal is provided to form a transmission path by using a switching circuit and a filter to separate a TD-SCDMA(Time Division-Synchronous CDMA) based transceiving signal from a DCS-based transceiving signal. CONSTITUTION: A diplexer(41) is connected with an antenna(40), and separates TD-SCDMA/DCS based signals from a GSM-based signal. A low pass filter(44) filters a GSM-based transmission signal. A band pass filter(45) filters a TD-SCDMA based transmission signal. A low pass filter(46) filters a DCS-based transmission signal. A switch(42) transmits the filtered GSM-based transmission signal to the diplexer(41), and transmits a GSM-based receiving signal separated from the diplexer(41) to an inner system. A switch(43) transmits the filtered DCS-based transmission signal to the diplexer(41), and transmits a TD-SCDMA or a DCS-based receiving signal separated from the diplexer(41) to the inner system.