Design method of analog low-pass filters with monotonic characteristics and arbitrary flatness.

In analog filters with monotonic amplitude characteristics, there exists a significant difference in the flatness between Butterworth filters and L filters. However, there are no reports on low-pass analog filters with characteristics that are intermediate of those two, that is, in which the amplitude is monotonic and the flatness is arbitrary. In this paper, by means of Jacobi polynomials, a mathematically closed transfer function of such a filter is proposed. The proposed transfer function incorporates those of Butterworth filters and L filters. Also, this transfer function can be realized at arbitrary order for both even and odd orders. © 1999 Scripta Technica, ElectronComm Jpn Pt 3, 82(8): 21–29, 1999 [ABSTRACT FROM AUTHOR]