By default, the filter is designed by the bilinear transform method, which is
recommended for most applications.
Tick (check) here: and the matched z-transform
will be used instead.
Warning: inspect the frequency response carefully if you use this option.
Click here for further information about the matched z-transform,
and about Bessel filters in particular.
By default, the frequency response graph has a linear magnitude scale.
If that is what you want, leave the following box blank.
If you want a logarithmic magnitude scale in dB,
enter the lower limit of the magnitude scale in dB here (e.g. -80).
Lower limit (dB), or blank for linear scale: