Signal Processing Toolbox

Convert Structure Button

This button opens a dialog box where you can specify a new structure to represent the current filter. All filters can be converted to the following representations:

• Direct form I
• Direct form II
• Direct form I transposed
• Direct form II transposed
• State-space
• Lattice ARMA

In addition, the following conversions are available for particular classes of filters:

• Minimum phase FIR filters can be converted to Lattice MA min. phase
• Maximum phase FIR filters can be converted to Lattice MA max. phase
• Allpass filters can be converted to Lattice allpass

See Filter Structures for more information about any of these representations.

When selected, the Use second-order sections check box instructs the tool to store the converted filter structure as a collection of second-order sections rather than as a monolithic higher-order structure. The subordinate Scale menu lets you select from the following options:

• None (default)
• L-2 (L² norm)
• L-infinity (L norm)

The ordering of the second-order sections is optimized for the selected scaling option. (The tf2sos function that performs the conversion is called with option 'down' for L² norm scaling, and with option 'up' for L norm scaling.)

Current Filter Information Region

Quantization Region