A power transmitter for wirelessly for providing power to a power receiver via an inductive power transfer signal. The power transmitter comprising a power transfer coil for generating the power transfer signal, a driver for generating a drive signal for the power transfer coil, the driver being arranged to, during a power transfer phase, generate the drive signal to employ a repeating time frame comprising at least a power transfer time interval and a transfer foreign object detection time interval, a receiver for receiving a message from the power receiver, a foreign object detector arranged to perform a foreign object detection (FOD) test, a communication coil for generating a communication signal, and a communication unit arranged to generate a communication control signal for the communication coil to provide the communication signal during a communication period, said communication unit being arranged to set the communication control signal to a first value during the communication period and to set the communication control signal to a second value during a communication foreign object detection time interval, the communication foreign object detection time interval occurring during the communication period.