Sensitivity of the band-edge selectivity of various classical filters

A new type of transitional filter based on summation of polynomials

“…Classical filters with degrees of freedom: Classical filters having one or more degrees of freedom in addition to order can be made to have transitional properties by trading off filter design parameters. Making filters more selective increases delay peaking in the passband edge [6]. Conversely, reducing selectivity improves delay and reduces time-domain distortion [7].…”