dfdpzp.m

很多matlab的源代码

function [num,den] = dfdpzp(tol)
% DFDPZP Interactive digital filter design by pole-zero placement.
%
%        DFDPZP(TOL) invokes the interactive digital filter design by 
%        pole-zero placement with tolerance, TOL, for snapping to the
%        grid [Default: 0.02].  Snaps ZEROS to unit circle OR POLES/ZEROS
%        to origin or real axis.	
%
%        [NUM,DEN] = DFDPZP returns NUM(z) & DEN(z) of designed 
%        H(z) = NUM(z)/DEN(z) (version 3.5 only)
%
%        Note: If running MATLAB 3.5,  type HELP DFDPZP3.
%              If running 4.x or 5.x,  type HELP DFDPZP4.


% ADSP Toolbox: Version 2.0 
% For use with "Analog and Digital Signal Processing", 2nd Ed.
% Published by PWS Publishing Co.
%
% Ashok Ambardar, EE Dept. MTU, Houghton, MI 49931, USA
% http://www.ee.mtu/faculty/akambard.html
% e-mail: [e-mail]
% Copyright (c) 1998


if nargin==0, tol = 0.02; end
if exist('version')==5
help dfdpzp4,eval('dfdpzp4');
else
[num,den]=eval('dfdpzp3(tol)');
end