Abstract: The present invention is directed towards methods, devices and a system for reducing negative influence on signals transmitted in one of at least two frequency bands. A power amplifier (18) and a modulation unit (16) are connected to each other via at least two connections (22, 24). A switch (20) is connected to at least one (24) of the two connections and arranged to break the connection between the modulation unit and the power amplifier when signals are to be transmitted from the modulation unit to the power amplifier on the other connection (22). In this way the radio frequency leakage back to the modulation unit when processing signals for radio transmission is reduced.