Acoustic antialiasing filter having one resistive element for digitized microphone.

Abstract

The synthetic method of electrical passive networks is successfully applied to the development of an acoustic antialiasing filter for an electret condenser microphone. The Butterworth type lowpass filter of order nine is realized as a tandem connection of an acoustic filter of order five and an electronic filter of order four which is imbeded in the microphone amplifier. The merit of this synthetic design is that the filter can be so realized with only one acoustic resistance that makes the adjustment at the production easy.