Adjustable filter for differential microphones.

摘要

A method and apparatus for providing a differential microphone (1) with a desired frequency response are disclosed. The desired frequency response is provided by operation of a filter (5) having an adjustable frequency response, coupled to the microphone. The frequency response of the filter is set by operation of a controller (6), also coupled to the microphone, based on signals received from the microphone. The desired frequency response may be determined based upon the distance between the microphone and a source of sound (S), and may comprise both a relative frequency response and absolute output level. The frequency response of the filter may comprise the substantial inverse of the frequency response of the microphone to provide a flat response. Futhermore, the filter may comprise a Butterworth filter. <IMAGE>