| 摘要 |
PURPOSE:To miniaturize and economize relay amplifiers distributed and arranged in automobile telephone and portable telephone systems, etc. CONSTITUTION:A down line amplifier circuit and an up line amplifier circuit connected between a base station side transmission/reception shared antenna connecting point 1 and a mobile station side transmission/reception shared antenna connecting point 2 are respectively constituted of input side filters 3 and 8 for suppressing the sneak path of opposite band signals, first amplifiers 4 and 9, intermediate filters 5 and 10 for making a noise figure small, second amplifiers 6 and 11 and output side filters 7 and 12 for which the attenuation of the opposite band signals is reduced. Thus, since the performance required for the filters are distributed to three filters, the standard of the respective filters is relaxed, a resonator with low non-load Q can be adopted and the amplifier is comprehensively miniaturized. |
