Transfer Fcn Lead or Lag

Implement discrete-time lead or lag compensator

• Library:

• Simulink / Discrete

• 

Description

The Transfer Fcn Lead or Lag block implements a discrete-time lead or lag compensator of the input. The instantaneous gain of the compensator is 1, and the DC gain is equal to (1-z)/(1-p), where z is the zero and p is the pole of the compensator.

The block implements a lead compensator when 0<z<p<1, and implements a lag compensator when 0<p<z<1.

Ports

Input

Port_1 — Input signal

scalar | vector

Input signal that the block applies the discrete-time lead or lag compensation to.

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

Output

Port_1 — Output signal

scalar | vector

Output signal that is discrete-time lead or lag compensation of the input sign.

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

Parameters

Pole of compensator (in Z plane) — Pole

0.95 (default) | scalar

Specify the pole of the compensator.

Programmatic Use

Block Parameter: PoleZ

Type: character vector

Value: real scalar

Default: '0.95'

Zero of compensator (in Z plane) — Zero of compensator

0.75 (default) | scalar

Specify the zero of compensator in the Z plane.

Programmatic Use

Block Parameter: ZeroZ

Type: character vector

Value: real scalar

Default: '0.75'

Initial condition for previous input — Initial condition for previous input

0.0 (default) | scalar

Specify the initial condition for the previous input.

Programmatic Use

Block Parameter: ICPrevInput

Type: character vector

Value: real scalar

Default: '0.0'

Initial condition for previous output — Initial condition for previous output

0.0 (default) | scalar

Specify the initial condition for the previous output.

Programmatic Use

Block Parameter: ICPrevOutput

Type: character vector

Value: real 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).

Block parameters always round to the nearest representable value. To control the rounding of a block parameter, enter an expression using a MATLAB^® rounding function into the mask field.

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 Lead and Lag Filters

Sample fixed-point implementations of a discrete lead filter and a discrete lag filter along with reference implementations in floating point.

Block Characteristics

Data Types	Boolean[a] | double | fixed point | integer | single
Direct Feedthrough	no
Multidimensional Signals	no
Variable-Size Signals	yes
Zero-Crossing Detection	no
[a] This block is not recommended for use with Boolean signals.

Extended Capabilities

C/C++ Code Generation
Generate C and C++ code using Simulink® Coder™.

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

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