Patent ID: 8520867

Claim:
An embedded audiphone, characterized by comprising: an extracorporeal unit that generates a transmission magnetic flux using an extracorporeal transmitter coil on the basis of an audible sound modulation transmission signal that is obtained by amplitude-modulating a carrier wave signal with the use of a sound collection signal obtained from a microphone; and an intracorporeal unit that is embedded in a skull under scalp, generates an induced electromotive force with the use of the transmission magnetic flux coming from the extracorporeal unit and an interlinked intracorporeal receiver coil, expands and contracts a transducer made of a magnetostrictive element with the use of the induced electromotive force, and therefore supplies vibrations corresponding to the sound collection signal to the skull as bone-conduction vibrations, wherein: the transducer is a rod-shaped magnetostrictive element, an induced electromotive force obtained from the intracorporeal receiver coil is supplied to a transducer driving coil that is wound on the transducer in order to make an excitation magnetic field pass through the rod shaped magnetostrictive element in a length direction, and the transducer expands and contracts in the length direction as a result; for the rod-shaped magnetostrictive element, a bias magnetic field is added to the length-direction excitation magnetic field of the rod-shaped magnetostrictive element with the use of an operating point setup unit made of a permanent magnet; and an amplitude demodulation circuit is omitted because of a self-demodulation function of the rod-shaped magnetostrictive element.