BIDIRECTIONAL FILTER FOR HALF-DUPLEX TYPE SIDE-BAND TRANSCEIVER AND ITS OPERATION METHOD

摘要

PROBLEM TO BE SOLVED: To decrease signal processing circuits and to reduce the unit price and needed electric power by arranging an intermediate filter stage in only one of a reception signal path and a transmit signal path which is selected as the function of operation mode of a base-band circuit. SOLUTION: The bidirectional filter 220 is equipped with a switching circuit 223 which is related to the intermediate filter stage 224 of the filter 220. The switching circuit 223 of a transceiver 200 has the intermediate filter stage 224 arranged in one of the reception signal path and transmit signal path which is selected as the function of operation mode of the base-band circuit 205. This intermediate filter state 224 itself is bidirectional, so the intermediate filter stage 224 is positioned in either of the reception signal path and transmit signal path, so that interfaces at respective end of the intermediate filter stage 224 operate for input and output alternately. The intermediate filter stage 224 of the transceiver is not limited to a specific frequency or frequency range.