User`s guide

Filter Realization Wizard
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3 Type a name for the new filter subsystem in the Block Name field. The
example uses
Butter SOS.
4 Press the Build button to create the specified filter subsystem in a new
model window.
5 Double-click the new Butter SOS block to see the Direct-Form II filter
realization that the Wizard created.
Note that in a subsystem with the Direct-Form I or II architecture, the filter
sections are connected using From and Goto blocks rather than being directly
wired together. This makes it easier to recognize and move filter sections in the
model window independently of each other.
Example 3: Nth Order Sections
Design a lowpass Butterworth filter using Nth order cascades:
1 At the MATLAB command line, compute the coefficients for the Nth order
sections by entering
[b1,a1] = butter(4,.25);
[b2,a2] = butter(3,.25);
2 Configure the Wizard to use these coefficient vectors as the numerator and
denominator of a Direct-Form II structure:
- Select
Direct-Form II from the Type menu.
- Type
{b1,b2} in the Numerator text field. Note that the numerator
coefficient vector for each section is entered as an element in a cell array.
Since this is a two-section filter, a two-cell array is specified in the