| 摘要 |
<p>First and second transfer paths (P1,P2) are provided between a first port (#1) connected to an antenna (ANT) and a second port (#2) connected to a transmitting/receiving circuit (10). On the first transfer path (P1), there are provided receiving filters (Rx1,Rx2,Rx2'), an amplifier circuit (LNA) and 90-degree hybrid circuits (12,14). On the second transfer path (P2), there is provided a transmitting filter (Tx1). A received signal as amplified by LNA is transferred to the port (#2) via the 90-degree hybrid circuits (12,14), but is not transferred to the second transfer path (P2). The transmitted signal is transferred to the second transfer path (P2) from the port (#2). In this way, any oscillation is prevented from occurring due to a positive feedback of the received signal. Thus, there are provided a transmitting/receiving filter device and a transmission device using the same that suppress insertion loss of transmission or reception frequency band, noise figure, and degradation of group delay characteristic and prevent any oscillation action.</p> |
