If the ripple is 0 dB a Butterworth characteristic is calculated.
If the ripple is > 0 dB a Chebyshev bandpass filter is calculated.
The Design procedure follows the Basic routines published by Jerry Hinshaw
and Shahrokh Monem - zadeh in 'Ham Radio Magazine' 01/1985 which are based on a Fortran IV
Program by Rook and Taylor. (1970)
Conversion from Basic to C++ by Dale Heatherington, 05/1996 and finally