Transfer Fcn Direct Form II

Implement Direct Form II realization of transfer function


Additional Math & Discrete / Additional Discrete


The Transfer Fcn Direct Form II block implements a Direct Form II realization of the transfer function that the Numerator coefficients and Denominator coefficients excluding lead parameters specify. The block supports only single input-single output (SISO) transfer functions.

The block automatically selects the data types and scalings of the output, the coefficients, and any temporary variables.

Data Type Support

The Transfer Fcn Direct Form II block accepts signals of the following data types:

  • Floating point

  • Built-in integer

  • Fixed point

For more information, see Data Types Supported by Simulink in the Simulink® documentation.


Numerator coefficients

Specify the numerator coefficients.

Denominator coefficients excluding lead

Specify the denominator coefficients, excluding the leading coefficient, which must be 1.0.

Initial condition

Set the initial condition.

Integer rounding mode

Specify the rounding mode for fixed-point operations. For more information, see Rounding (Fixed-Point Designer). in the Fixed-Point Designer™ documentation.

Saturate to max or min when overflows occur

Select to have overflows saturate to the maximum or minimum value that the data type can represent. Otherwise, overflows wrap.

When you select this check box, saturation applies to every internal operation on the block, not just the output or result. In general, the code generation process can detect when overflow is not possible. In this case, the code generator does not produce saturation code.


Data Types

Double | Single | Base Integer | Fixed-Point

Direct Feedthrough


Multidimensional Signals


Variable-Size Signals


Zero-Crossing Detection


Code Generation


Introduced before R2006a

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