| 摘要 |
An arrangement of hybrid couplers, selectively removing RF amplifiers from a receiving path from an antenna back to a receiver in response to an event, the event switching impedances of switchable impedances connecting to ports of the hybrid couplers, between a matching impedance and mismatching impedance. The matching and mismatching impedances change coupling characteristics of the hybrid couplers between a normal coupling and a bypass coupling. In the normal coupling the hybrid couplers provide port-to-port coupling placing the RF amplifiers within the receiving path and, in the bypass coupling, the hybrid couplers provide port-to-port coupling bypassing the RF amplifiers. Optionally, transmitted signal power is detected to identify transmit and receiving intervals. During detected transmit intervals, isolation switches isolate the RF amplifiers from the feedback path and, during receiving intervals and, during detected receiving intervals, the isolation switches RF amplifiers into the feedback path to amplify reception signals. Optionally a hybrid coupler switch is placed between the two circulators to increase the isolation in the RX mode reducing feedback to the LNA's.
|
