A note on trapezoidal digital filter design

Abstract

A simple design procedure to achieve an ideal trapezoidal low pass filter whose transfer function is unity for f ≤ FL, linearly goes to zero, in the interval FL < f ≤ FH and is zero for f > FH is described. Design considerations for practical implementation of the filter and specific illustrations are included. The transfer function performance of our practical design approximations to the ideal trapezoidal filter achieves superior stop band rejection to that achieved by the usual approximations to the H(f) = 1,0 ≤ |f| ≤ FH,H(f)= 0|f| > FH ideal filter. © 1973.