The concept of "increasing roll off rate with increasing filter order" applies only to butter worth or also chebyshev and other filter types?
1 Answer
assuming it's a low-pass filter and assuming that the filter order equals the number of poles and there are no zeros in the s-domain transfer function, then the rolloff at the edge of the passband through the stopband is -20 dB/decade (or -6 dB/octave) multiplied by the order of the filter.
now Butterworth and Tchebychev Type 1 filters have no zeros.
Tchebychev Type 2 and Elliptical filters have zeros, so the ultimate rolloff is not there, the gain remains at the stopband level.
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$\begingroup$ yes, i think that i got the spelling of it most originally. hence why the polynomial functions are shown as $$ T_n(x) $$ but there are others who think differently. $\endgroup$ Aug 21, 2020 at 21:11