Allpass Transfer Function The numerator of a real-coefficient allpass transfer function is said to be the mirror- image polynomial of the denominator, and vice versa We shall use the notation DM(z)to denote the mirror-image polynomial of a degree-M polynomial DM(z),i.e DM(2=2DM(2 Copyright C 2001, S K Mitra5 Copyright © 2001, S. K. Mitra Allpass Transfer Function • The numerator of a real-coefficient allpass transfer function is said to be the mirror￾image polynomial of the denominator, and vice versa • We shall use the notation to denote the mirror-image polynomial of a degree-M polynomial , i.e., DM (z) ~ DM (z) D (z) z DM (z) M M − = ~