Valid input arguments and values for specification object and method
OPTS = designopts(D,METHOD)
OPTS = designopts(D,METHOD) returns
a structure array with the default design parameters used by the design
METHOD must be
one of the options returned by
help(D,METHOD) to get a description
of the design parameters.
If you have DSP System Toolbox™ software
OPTS has the
if at least one of the structures available for that design method
is supported by System objects. However, not all structures for that
design method are supported by System objects.
Butterworth Filter Design Options
Create a lowpass filter with a numerator and denominator order of 10 and a 3-dB frequency of 0.2π rad/sample. Obtain the default design parameters for a Butterworth design. Test whether the filter structure is a direct-form II biquad.
D = fdesign.lowpass('Nb,Na,F3dB',10,10,0.2); OPTS = designopts(D,'butter')
OPTS = struct with fields: FilterStructure: 'df2sos' SOSScaleNorm: '' SOSScaleOpts: [1x1 fdopts.sosscaling] SystemObject: 0
if isequal(OPTS.FilterStructure,'df2sos') fprintf('The default filter structure is Direct-Form II\n'); fprintf('with second-order sections.\n'); end
The default filter structure is Direct-Form II
with second-order sections.