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Verify if discrete-time System object filter is in second-order sections form



flag = issos(sysobj) determines whether the filter System object™ is in second-order sections (SOS) form, returning a logical 1 if true and a logical 0 if false.


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By default, fdesign and design functions return SOS filters when possible. This example designs a lowpass SOS filter that uses fixed-point arithmetic.

d = fdesign.lowpass('n,fp,ap,ast',40,0.55,0.1,60);
hd = design(d,'ellip','SystemObject',true);

Using the issos function, verify whether the designed filter is in SOS form.

IsSOS = issos(hd)
IsSOS = logical

The filter is in second-order section form.

Output Arguments

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Flag to determine whether the filter is in second-order sections (SOS) form, returned as a logical scalar. If the filter is in SOS form, issos returns a logical 1, else it returns a logical 0.

Data Types: logical

Introduced in R2011a