Verify if discrete-time System object filter is in second-order sections form
Design Lowpass SOS Filter
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);
issos function, verify whether the designed filter is in SOS form.
IsSOS = issos(hd)
IsSOS = logical 1
The filter is in second-order section form.
sysobj — Input filter
filter System object
Input filter, specified as one of the following filter System objects:
flag — Flag to determine if filter is in SOS form
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,
returns a logical
1, else it returns a logical