www.gusucode.com > signal 工具箱matlab源码程序 > signal/@dfilt/@basefilter/zplane.m
function [z,p,k] = zplane(Hb,varargin) %ZPLANE Z-plane zero-pole plot. % ZPLANE(Hb) plots the zeros and poles of the discrete-time filter Hb with the % unit circle for reference. Each zero is represented with a 'o' and each % pole with a 'x' on the plot. Multiple zeros and poles are indicated by the % multiplicity number shown to the upper right of the zero or pole. % % See also DFILT. % Copyright 1999-2004 The MathWorks, Inc. Hd = dispatch(Hb); if nargout>0, [z,p,k] = zpk(Hd); else [Hb, opts] = freqzparse(Hb, varargin{:}); fvtool(Hb, 'polezero', opts); end % [EOF]