image, as well as the following text, is derived from Image:Butterworth_response.png. Generated in gnuplot with the following script (save as ellip.plt and
Filter Response (4th Order).svg is a vector version of this file. It should be used in place of this PNG file when not inferior. File:CauerResponse1.png →
Filter Response (4th Order, Detail).svg is a vector version of this file. It should be used in place of this PNG file when not inferior. File:CauerResponse2