Design of Digital Low-Pass Filters for Time-Domain Recursive Filtering of ImpactAcceleration Signals

摘要

The purpose of this report is to present simplified and portable computerprograms to design and implement recursive digital Butterworth filters. The design method described in the report uses the bilinear transformation to convert the well established analog design to digital formulation. Fortran codes for the design and implementation of the filter are included in the report. The resulting design is compared to another filter proposed in SAE J211 guideline for filtering impact acceleration signals. Although both design methods produced filters which are within corridors prescribed in the J211 guideline, the standard design produces a Butterworth-like response whereas the J211 design does not. Additionally, the standard design methods and the implementation algorithms allow the design of any even order filter which may be required for filtering other long duration signals.