I have a question about design Bessel filter.

To find the pole of Bessel filter, the frequency normalization process required the division of Thomson’s values by a factor(Bessel Normalizing Factors), as follows:

But I using these factor to calculate the pole of the Bessel filter, the pole are not same as MATLAB besselap.m, as follows:

Edit

This problem has troubled me for a long time.

Herbert

But I using these factor to calculate the pole of the Bessel filter

Maybe some lines of code of your calculations could be helpful ...?