Patent ID: 6285769
Filing Date: 2001-09-04
Classification: H04R

Abstract:
A microphone system for the detection of pressure variations in a medium, comprising:transduction means for the conversion of said pressure variations into displacement of said transduction means;detection means for the conversion of said displacement into variations of an electrical output;feedback means for the cancellation of said displacement, whereby nonlinearities of said transduction means or said detection means are reduced or eliminated from the output of said microphone system;wherein said transduction means is a metal ribbon, wherein said detection means is a tunneling current detector arranged proximally to said metal ribbon, said tunneling current detector consisting of a probe and a transimpedance amplifier, a suitable bias voltage being applied between said metal ribbon and said tunneling current detector, wherein said feedback means is analog electromagnetic feedback, said analog electromagnetic feedback consisting of a comparator taking as input the output of said tunneling current detector and a reference voltage, said comparator charging an integrating capacitor, said integrated comparison result controlling a variable current source supplying current to said metal ribbon, said metal ribbon mounted in a magnetic field transverse to the plane of said ribbon, whereby displacements in the position of said ribbon will be detected, causing the production of a current through said ribbon which will cause a restoring force to be developed in said ribbon.