An apparatus for emitting and receiving radio-frequency signals includes a circuit to cancel interference. The apparatus transmits and receives signals using an antenna, and isolates the transmission and receiving circuitry. The circuit taps a first part of a signal to be transmitted, and controls the amplitude and phase of this signal. The circuit then introduces the first part of the signal into the receiver after the first part of the signal has been amplified and phase-shifted, so as to cancel in the receiver interference due to portions of the signal that have undesirably entered the receiver.