A rotatable coupling includes an input housing rotatably coupled to an output housing by a tube fixed to the output housing and on which tube the input housing rotates. The coupling includes two magnetic flux concentrators disposed about the tube and defining therebetween an annular cavity, a first concentrator fixed to the input housing and a second concentrator fixed to the output housing, such that relative rotation of the housings causes relative rotation of the concentrators on either side of the annular cavity. The coupling includes concentric coils disposed within the annular cavity that permit power transfer across the coupling, a first coil fixed to the input housing and a second coil fixed to the output housing; an emitter fixed to the input housing; and a receiver fixed to the output housing and positioned to receive the signals from the emitter during the relative rotation of the housings.