| 摘要 |
An amplifier unit to adapted to be placed in an antenna mast of a radio system that uses time division duplex. The amplifier unit includes transmitting and receiving branches in parallel, with the transmitting branch being used as a bypass path for a low noise amplifier (LNA) in the receiving branch. The unit is set to the transmitting mode, receiving mode and bypass mode by means of pin diode switches. A passive bypass mode comes into effect automatically, if the unit loses its supply voltage. At least one pin switch is located transversely in the transmitting branch for switching off the unit, when it is set to the receiving mode. The structure of the unit advantageously includes another, redundant, transmitting branch with series switches, which branch is used for improving the characteristics of the transmission path for transmitting signals, when the biasing of the pin switches is possible. |
