Abstract: A noise suppressing microphone employing a thin film of piezoelectric material sandwiched between two conductive layers, one of which is laminated to a flat inflexible laminate. The sandwich is embedded in a mechanical sound filter except for one exposed face which is placed in contact with a user's body for sound pickup.

Abstract: An impedance matching circuit couples a microphone's output to a radio's microphone input. A tap circuit is coupled to the microphone's output for extracting an audio signal therefrom. An amplifier circuit having DC blocking circuitry is coupled to the tap circuit. An audio transformer is also provided with its primary and secondary windings defining a turns ratio of approximately 1:1. The primary winding has a characteristic DC resistance that is less than approximately 100 ohms. The secondary winding has an impedance that is within a prescribed impedance range of the microphone input. A driver circuit is coupled between the amplifier circuit and audio transformer for continuously driving the audio transformer.

Abstract: A head-supported two-way communication system. The system combines a thin bstrate forehead or head-bone microphone, a noise filter embedding the microphone, a universal impedance matcher connecting the microphone to a two-way radio, an unobstructed and unfettered-access push-to-talk switch, and a pair of rigidly positionable noise protected speakers, all secured to a head-supported structure permitting proper location of the embedded microphone, the switch, and the speakers for a particular user and application.