Digital-Filter-Based Compensation of Case Effect in Sound-Level Meters

摘要

The methodology for the design of a digital filter, which should compensate the effect of reflections and diffraction from the sound-level meter's casing (the so-called case effect), is presented. The coefficients of the family of the finite impulse response (FIR) filters, which were selected to fulfill the requirements of the compensation, were obtained in the MATLAB environment using the Remez algorithm. The frequency response of the selected designed filter are given. The chosen FIR filter was implemented in an on-chip Enhanced Filter Coprocessor of a fixed point 24-bit digital signal processor of a sound-level meter.