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validstructures

Structures for specification object with design method

Syntax

filtstruct = validstructures(D,'Systemobject',true)
filtstruct = validstructures(D,METHOD,'Systemobject',true)

Description

filtstruct = validstructures(D,'Systemobject',true) returns a structure of cell arrays, filtstruct, which contains a set of valid filter structures for the filter specification object, D. When you set 'Systemobject' to true, validstructures returns a list of structures that support filter System objects. Each field in filtstruct lists a set of filter structures for the design method specified.

filtstruct = validstructures(D,METHOD,'Systemobject',true) returns the valid structures for the filter specification object, D, and the design method, METHOD, in a cell array of character vectors.

Examples

collapse all

Design a default lowpass filter specification object. Return all valid design methods and structures in a structure array. Display the fieldnames to see all valid design methods. Display the valid filter structures for the equiripple field.

D = fdesign.lowpass;
filtstruct = validstructures(D);

fn = fieldnames(filtstruct)
fn = 8×1 cell array
    'butter'
    'cheby1'
    'cheby2'
    'ellip'
    'equiripple'
    'ifir'
    'multistage'
    'kaiserwin'

strs = eval(['filtstruct.' fn{5}])
strs = 1×4 cell array
    'dffir'    'dffirt'    'dfsymfir'    'fftfir'

Create a highpass filter of order 50 with a 3-dB frequency of 0.2. Obtain the available structures for a Butterworth design.

D = fdesign.highpass('N,F3dB',50,0.2);
C = validstructures(D,'butter')
C = 1×6 cell array
    'df1sos'    'df2sos'    'df1tsos'    'df2tsos'    'cascadeallpass'    'cascadewdfallpass'

Introduced in R2009a

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