Patent ID: 6084972
Filing Date: 2000-07-04
Classification: H04R

Abstract:
An integrated microphone/amplifier unit comprising:a microphone for generating a microphone signal in response to sound waves;an amplifier, having an input coupled to the microphone and an output coupled with an output connection of the microphone/amplifier unit, for supplying an amplified microphone signal, the amplifier comprising a field-effect transistor (FET) configured as a source-follower, a source of the FET being coupled to the output of the amplifier so as to provide an unbalanced output; andfirst and second feed connections for connection with a supply source, the output connection of the amplifier being capacitively coupled, through a first capacitive coupling, with the first feed connection, and the first feed connection being capacitively coupled, through a second capacitive coupling, with the second feed connection, wherein capacitance values of both the first and second capacitive couplings are approximately equal to each other, wherein the first and second capacitive couplings suppress audible interference otherwise appearing in the amplified microphone signal appearing at the output and attributable to induced high frequency signals.