Transfer Fcn Direct Form II

Implement Direct Form II realization of transfer function

• Library:

• Simulink / Additional Math & Discrete / Additional Discrete

• 

Description

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.

Ports

Input

Port_1 — Input signal

scalar | vector

Input signal, specified as a scalar or vector.

Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64 | fixed point

Output

Port_1 — Output signal

scalar | vector

Output signal, specified as a scalar or vector.

Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64 | fixed point

Parameters

Numerator coefficients — Numerator coefficients

[0.2 0.3 0.2] (default) | vector

Specify the numerator coefficients as a vector.

Programmatic Use

Block Parameter: NumCoefVec

Type: character vector

Values: vector

Default: '[0.2 0.3 0.2]'

Denominator coefficients excluding lead — Denominator coefficient

[-0.9 0.6] (default) | vector

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

Programmatic Use

Block Parameter: DenCoeffVec

Type: character vector

Values: vector

Default: '[-0.9 0.6]'

Initial condition — Initial condition

0.0 (default) | scalar

Specify the initial condition as a scalar.

Programmatic Use

Block Parameter: vinit

Type: character vector

Values: scalar

Default: '0.0'

Integer rounding mode — Rounding mode for fixed-point operations

Floor (default) | Ceiling | Convergent | Nearest | Round | Simplest | Zero

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

Programmatic Use

Block Parameter: RndMeth

Type: character vector

Values: 'Ceiling' | 'Convergent' | 'Floor' | 'Nearest' | 'Round' | 'Simplest' | 'Zero'

Default: 'Floor'

Saturate to max or min when overflows occur — Method of overflow action

off (default) | on

When you select this check box, 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.

Programmatic Use

Block Parameter: DoSatur

Type: character vector

Values: 'off' | 'on'

Default: 'off'

Model Examples

Fixed-Point Filters

Bit-true implementations of fixed-point direct type I and II filters with time-varying and time-invariant coefficients. These filters use the fundamental capabilities in Fixed-Point Designer™ and work with the autoscaling tools.

Block Characteristics

Data Types	double | fixed point | integer | single
Direct Feedthrough	no
Multidimensional Signals	no
Variable-Size Signals	no
Zero-Crossing Detection	no

Extended Capabilities

C/C++ Code Generation

Generate C and C++ code using Simulink® Coder™.

The code generator does not explicitly group primitive blocks that constitute a nonatomic masked subsystem block in the generated code. This flexibility allows for more efficient code generation. In certain cases, you can achieve grouping by configuring the masked subsystem block to execute as an atomic unit by selecting the Treat as atomic unit option.

PLC Code Generation
Generate Structured Text code using Simulink® PLC Coder™.

Fixed-Point Conversion
Design and simulate fixed-point systems using Fixed-Point Designer™.