| 摘要 |
This application concerns a duplexer including a transmit / receive switch 14. The transmit / receive switch has a common input / output port which is connected to an antenna, a port 6 connected to receiving apparatus 8, and a port 10 connected to transmitting apparatus 12. The switch connects the common port to either the transmit port or the receive port. In its most general form, the invention involves monitoring 32 the RF power at the common port and controlling 18 the switch 14 to switch from the transmit port to the receive port upon the power falling below a threshold level. In a preferred embodiment the switching occurs only when a gating signal 20 has been received and subsequently the RF power fall below the threshold. This increases the speed of switching compared to prior art systems which rely on the gate signal alone, whilst still protecting the receiver from the damage it could suffer if it received the transmit signal. The invention finds particular application in the field of radar. |
