This filter has shown up unceremoniously in recent SigmaStudio betas, and it's immensely useful.
Previously, to make a sharp filter we had to cascade a number of first and second-order sections, Their frequency and Q had to be figured with a filter-design program. Now, SigmaStudio does the work for you. Below are two 4 KHz "brick wall" Chebyshev telephone filters, done the old way and the new way:
The Order number N (number of poles in the filter) must be even. If you change N with the green button, it chooses even numbers. You can go ahead and type an odd number in the box, but the resulting response is incorrect. Thus I'm comparing a 12-pole Nth-Order filter to an 11-pole assembled filter. Here the Nth-Order filter uses three more instructions (60 instead of 57), but works much better as shown below: