www.gusucode.com > signal 工具箱matlab源码程序 > signal/fdesign.m
function this = fdesign %FDESIGN Digital Filter Design. % D = FDESIGN.<RESPONSE> returns a set of specifications that can be used % to design filters specified by RESPONSE, such as lowpass, highpass, and % many other types of filters. Type "help fdesign/responses" to get the % list of supported <a href="matlab:help fdesign/responses">responses</a>. % % The design process creates the filter coefficients and associates a % particular filter structure to those coefficients. To design a filter % use the following command: % <a href="matlab:help fdesign/design">design</a> - Design the filter from the specifications. % % Other functions that can aid the design process: % <a href="matlab:help fdesign/designmethods">designmethods</a> - Available design methods for the specifications given. % <a href="matlab:help fdesign/help">help</a> - Display help for a particular design method. % <a href="matlab:help fdesign/designopts">designopts</a> - Return a structure of design options to be used with <a href="matlab:help fdesign/design">design</a>. % <a href="matlab:help fdesign/designoptions">designoptions</a> - Show all design options available for a particular design. % <a href="matlab:help fdesign/validstructures">validstructures</a> - Show valid filter structures for a particular design. % % To process data through the filter, see <a href="matlab:help dfilt/filter">dfilt/filter</a> and <a href="matlab:help mfilt/filter">mfilt/filter</a>. % % EXAMPLE - Design a minimum order lowpass filter with % % a normalized passband frequency of 0.2, % % a stopband frequency of 0.22, % % a passband ripple of 1 dB, % % and a stopband attenuation of 60 dB. % d = fdesign.lowpass('Fp,Fst,Ap,Ast',0.2, 0.22, 1, 60); % f = design(d, 'equiripple'); % Design an FIR equiripple filter % info(f) % View information about filter % % % Other designs can be performed for the same specifications % designmethods(d,'iir'); % List the available IIR design methods % f = design(d, 'ellip') % Design an elliptic IIR filter (SOS) % fvtool(f) % visualize various filter responses % input = randn(100,1); % output = filter(f,input); % Process data through the elliptic filter. % % % Many designs such as equiripple allow for various options to % % be specified at design time. % % For more information enter "doc fdesign" at the MATLAB command line. % % <a href="matlab:help signal">Signal Processing Toolbox TOC</a> % % See also FILTERBUILDER, FDESIGN/SETSPECS, FDESIGN/NORMALIZEFREQ. % Copyright 1999-2006 The MathWorks, Inc. error(message('signal:fdesign:fdesign:Package', 'FDESIGN.*', 'h = fdesign.lowpass', 'help fdesign/responses')); % [EOF]