www.gusucode.com > signal 工具箱matlab源码程序 > signal/+fdesign/@halfband/halfband.m
classdef (CaseInsensitiveProperties=true, TruncatedProperties=true) halfband < fdesign.abstracttypewspecs & dynamicprops
%HALFBAND Construct a halfband filter designer.
% D = FDESIGN.HALFBAND constructs a halfband filter designer D.
%
% D = FDESIGN.HALFBAND('TYPE',TYPE) initializes the filter designer
% 'Type' property with TYPE. TYPE must be either 'Lowpass' or 'Highpass'
% and is not case sensitive.
%
% D = FDESIGN.HALFBAND(SPEC) initializes the filter designer
% 'Specification' property to SPEC. SPEC is one of the following
% strings and is not case sensitive:
%
% 'TW,Ast' - (minimum order, default)
% 'N'
% 'N,Ast'
% 'N,TW'
%
% where
% Ast - Stopband Attenuation (dB)
% N - Filter Order
% TW - Transition Width
%
% By default, all frequency specifications are assumed to be in
% normalized frequency units. Moreover, all magnitude specifications are
% assumed to be in dB.
%
% Different specification types may have different design methods
% available. Use DESIGNMETHODS(D) to get a list of design methods
% available for a given SPEC.
%
% D = FDESIGN.HALFBAND(SPEC, SPEC1, SPEC2, ...) initializes the filter
% designer specifications with SPEC1, SPEC2, etc...
% Use GET(D, 'DESCRIPTION') for a description of SPEC1, SPEC2, etc.
%
% D = FDESIGN.HALFBAND(TransitionWidth, Astop) uses the default
% SPEC ('TW,Ast') and sets the transition width and stopband
% attenuation.
%
% D = FDESIGN.HALFBAND(...,Fs) specifies the sampling frequency (in
% Hz). In this case, the transition width, if specified, is also in Hz.
%
% D = FDESIGN.HALFBAND(...,MAGUNITS) specifies the units for any
% magnitude specification given in the constructor. MAGUNITS can be one
% of the following: 'linear', 'dB', or 'squared'. If this argument is
% omitted, 'dB' is assumed. Note that the magnitude specifications are
% always converted and stored in dB regardless of how they were
% specified.
%
% % Example #1
% %Design a minimum order equiripple halfband lowpass filter.
% %Compare to an elliptic IIR halfband filter
% d = fdesign.halfband('Type','Lowpass',.01, 80);
% Hfir = design(d,'equiripple');
% Hiir = design(d,'ellip');
% fvtool(Hfir,Hiir)
%
% % Example #2
% %Design a 80th order equiripple halfband highpass filter
% %with 70dB of stopband attenuation.
% d = fdesign.halfband('Type','Highpass','N,Ast',80,70);
% Hd = design(d,'equiripple');
%
% % Example #3
% %Design a 42th order equiripple halfband lowpass filter
% %with a controlled transition width.
% d = fdesign.halfband('Type','Lowpass','N,TW', 42, .04);
% designmethods(d);
% Hd = design(d,'firls');
%
% For more information about halfband filters, see the
% <a href="matlab:web([matlabroot,'\toolbox\dsp\dspdemos\html\firhalfbanddemo.html'])">FIR Halfband Filter Design</a> demo.
%
% See also FDESIGN, FDESIGN/SETSPECS, FDESIGN/DESIGN.
% Copyright 2004-2015 The MathWorks, Inc.
%fdesign.halfband class
% fdesign.halfband extends fdesign.abstracttypewspecs.
%
% fdesign.halfband properties:
% Response - Property is of type 'ustring' (read only)
% Description - Property is of type 'string vector' (read only)
% Type - Property is of type 'halfbandresponseTypes enumeration: {'Lowpass','Highpass'}'
% Specification - Property is of type 'halfbandSpecsTypes enumeration: {'TW,Ast','N','N,Ast','N,TW'}'
%
% fdesign.halfband methods:
% getconstructor - Return the constructor for the specification type.
% getmask - Get the mask.
% getmeasureconstructor - Get the measureconstructor.
% getnoiseshapefilter - Get the noiseshapefilter.
% minwordlengthApass - Determine the passband ripples of the minimum wordlength filter
% noiseshape - Noise-shape the FIR filter Hd
% noiseshapeparetobands - Returns the band where to measure the frequency
% passbandspecmet - Check whether passband response is within spec.
% propstoadd - Return the properties to add to the parent object.
% propstocopy - Returns the properties to copy that are not part of the specs.
% set_type - PreSet function for the 'type' property
% setspecs - Set the specs.
properties (AbortSet, SetObservable, GetObservable)
%TYPE Property is of type 'halfbandresponseTypes enumeration: {'Lowpass','Highpass'}'
Type = 'Lowpass';
end
properties (Access=protected, SetObservable, GetObservable)
%PRIVTYPE Property is of type 'halfbandresponseTypes enumeration: {'Lowpass','Highpass'}'
privType = 'Lowpass';
end
properties (SetObservable, GetObservable)
%SPECIFICATION Property is of type 'halfbandSpecsTypes enumeration: {'TW,Ast','N','N,Ast','N,TW'}'
Specification;
end
methods % constructor block
function this = halfband(varargin)
% this = fdesign.halfband;
this.Response = 'Halfband';
this.Specification = 'TW,Ast';
this.setspecs(varargin{:});
capture(this);
end % halfband
end % constructor block
methods
function set.Type(obj,value)
% Enumerated DataType = 'halfbandresponseTypes enumeration: {'Lowpass','Highpass'}'
value = validatestring(value,{'Lowpass','Highpass'},'','Type');
obj.Type = set_type(obj,value);
end
%------------------------------------------------------------------------
function set.privType(obj,value)
% Enumerated DataType = 'halfbandresponseTypes enumeration: {'Lowpass','Highpass'}'
value = validatestring(value,{'Lowpass','Highpass'},'','privType');
obj.privType = value;
end
%------------------------------------------------------------------------
function value = get.Specification(obj)
value = get_specification(obj,obj.Specification);
end
%------------------------------------------------------------------------
function set.Specification(obj,value)
value = validatestring(value,getAllowedStringValues(obj,'Specification'),'','Specification');
obj.Specification = set_specification(obj,value);
end
end % set and get functions
methods
function vals = getAllowedStringValues(obj,prop)
if strcmp(prop,'Specification')
vals = {'TW,Ast','N','N,Ast','N,TW'}';
else
vals = {};
end
end
end
methods (Access = protected)
%This function defines the display behavior for the class
%using matlab.mixin.util.CustomDisplay
function propgrp = getPropertyGroups(obj)
propList = get(obj);
cpropList = propstoadd(obj.CurrentSpecs);
propList = reorderstructure(propList,'Response','Specification','Description','Type',cpropList{:});
if propList.NormalizedFrequency
propList = rmfield(propList, 'Fs');
end
propgrp = matlab.mixin.util.PropertyGroup(propList);
end
end
methods % public methods
cSpecCon = getconstructor(this)
[F,A] = getmask(this,fcns,rcf,specs)
measureconstructor = getmeasureconstructor(this)
nsf = getnoiseshapefilter(this,nnsf,cb)
Apass = minwordlengthApass(f,md,Astop)
Hns = noiseshape(this,Hd,WL,args)
bands = noiseshapeparetobands(this)
flag = passbandspecmet(Hf,Hd,ng)
p = propstoadd(this)
p = propstocopy(this)
type = set_type(this,type)
setspecs(this,varargin)
end % public methods
methods (Hidden) % possibly private or hidden
varargout = currentfdesigndesignmethods(this,varargin)
[xlim,ylim] = thispassbandzoom(this,fcns,Hd,hfm)
end % possibly private or hidden
end % classdef