Elliptic (Cauer) Low pass filter design

[tblues87]

Hi
can someone suggest which design to use for active low pass filter 4th order. I have tried Tow - Thomas filter (Biquad filter) with 4 op amps 2nd order in cascade, but the ripple in pass band doesn't do to the -1dB and also one peak goes over 0 dB.
I'm asking because with transfer function, from which I calculated elements, in Matlab I got perfect results with Bode.

Thank you

 

[Laplace]

Are you saying that in theory the filter performance was perfect but in practice the filter you built and tested did not perform as well? What method did you use to tune the filter?

 

[tblues87]

I compared transfer function from matlab with transfer function of the circuit, for each section.