SHARED CIRCUIT OF TRANSMITTER-RECEIVER FOR MOBILE FULL-DUPLEX RADIO EQUIPMENT

摘要

PURPOSE:To effectively use whole range of an available area by switching the signal from a transmitter to an antenna and the signal from the antenna to a receiver so that each of them passes one band filter and the frequency difference between respective pass bands is fixed. CONSTITUTION:Changeover switches 140 and 142 are manually switched so that the transmission signal from a transmitter 60 passes one of band filters 162 to 165 and is supplied to a circulator 120. Changeover switches 141 and 143 are switched in accordance with changeover switches 140 and 142 so that the reception signal from a circulator 122 passes one of band filters 166 to 169 and the frequency difference between the pass band of the transmission-side filter and that of the reception-side filter is always fixed. Thus, a bad influence due to detour of the transmission wave of its own station or penetration of the transmission wave of another station other than the communication destination is eliminated.