phases,thus non-constant group delays.The greatest deviation from constant group delay occurs in all cases at either the edge of the passband,or within the transition band.In general,the Chebyshev type II approximation gives the smallest delay in the passband, and the widest region of the passband over which the delay is approximately constant. However,if constant group delay is not required,the elliptic approximation gives the lowest order system function. Following are some sample elliptic filter designs.Also see OSB Example 7.6. Elliptic Filter,sth Order Exceeds Design Specifications Elliptic Filter,5th Order Pole-zero plot 号-20 28 无4 元2 34 -0.5 0.5 Imputse Response 0.2 0. 4 2 34 m,n 20 Froquency,o Figre 1:Magnitede Plot Passband Detsil,Group Dey Figure Pole-Zero Plot,Impulse Respose 2.Stopband edge 0.6m. 3.Maximum passband gain =0 dB. 5 Maximum passband gain0dB. -30dB 8thus non-constant group delays. The greatest deviation from constant group delay in all cases at either the edge of the passband, or within the transition band. In the Chebyshev type II approximation gives the smallest delay in the passband, widest region of the passband over which the delay is approximately constant. er, if constant group delay is not required, the elliptic approximation gives the order system function. • are some sample elliptic filter designs. Also see OSB Example 7.6. phases, general, occurs and the Howev lowest Following 8