In order to reduce the size of a duplex radio communication transceiver such as a mobile telephone, this transceiver is constructed of a transmitting and receiving duplexer, a filter to be coupled to the duplexer, an amplifier for amplifying a signal received, and a filter to be connected with the output...http://www.google.fr/patents/US4792939?utm_source=gb-gplus-shareBrevet US4792939 - Duplex radio communication transceiver
