0
$\begingroup$

The concept of "increasing roll off rate with increasing filter order" applies only to butter worth or also chebyshev and other filter types?

$\endgroup$

1 Answer 1

1
$\begingroup$

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.

$\endgroup$
2
  • $\begingroup$ Tchebychev ?? same as chebyshev? $\endgroup$
    – DSP_CS
    Aug 21, 2020 at 16:43
  • $\begingroup$ 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

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.