7.3 Digital Filter Design: Basic Approaches An analog transfer function to be denoted as Ha(s)=Pa(s)/Da(s) where the subscript“a”specifically indicates the analog domain A digital transfer function derived from H(s)shall be denoted as G(Z=P(Z/D(Z§7.3 Digital Filter Design: Basic Approaches • An analog transfer function to be denoted as Ha(s)= Pa(s) / Da(s) where the subscript “a” specifically indicates the analog domain • A digital transfer function derived from Ha(s) shall be denoted as G(z)=P(z)/D(z)