www.gusucode.com > signal 工具箱matlab源码程序 > signal/+fspecs/@lpcutoffwapas/ellip.m
function Hd = ellip(this, varargin) %ELLIP Elliptic digital filter design. % Author(s): V. Pellissier % Copyright 2005 The MathWorks, Inc. nfreq = this.NormalizedFrequency; normalizefreq(this, true); % Design prototype filter for any fp, to keep things simple, we make fp % equal to F3dB hs = fspecs.lppassastop(this.FilterOrder,this.F3dB,this.Apass,this.Astop); Hproto = ellip(hs,varargin{:}); Hproto.setfdesign(hs); % Find 3 db point measurements = measure(Hproto); % Apply frequency transformation to obtain final filter Hd = iirlp2lp(Hproto,measurements.F3dB,this.F3dB); Hd.setfmethod(Hproto.getfmethod); normalizefreq(this, nfreq); % [EOF]