Butterworth Bandpass Filter

I am trying to design an 8th order butterworth bandpass filter with the following specs:-

Fs = 400e6 % sampling frequency

% -3dB cut offs at 16.7e6 and 24.9e6

% -20dB cut offs at 15.2e6 and 25.5e6

I have used various tools including filterbuilder , fdatool, fdesign etc. Unfortunately there seem to be some limitations in the design aspect. If I specify my order then I loose out on the other design options. Is there any possible way to design such a filter.

Thanks

A

Answer 1

[Jan]

As far as I understood: no. If you specify the order of the Butterworth filter, you can define the cut offs of a band pass filter just at 2 frequencies.