Low Phase Shift Differential FIR Filter Design

Abstract

A low-phase shift and real-time differential estimation is a common problem in the control design. When linear phase shift filters are used at the system’s output, a strong performance loss appears with the increased phase shift. This paper presents a new FIR weights determination method focused on low-pass and differential filter design. The primary goal of this method is to minimize the phase shift caused by the differential FIR filter inside the control unit. In this case, the filter fits a defined polynomial to an asymmetric data set, then calculates a specified weighted sum. This feature allows reducing the value of the phase shift, even for differential estimation, and especially for the low-frequency spectrum. Moreover, the proposed solution results in LS optimal local differentiation based on the filter design.