Version:

Last Modified: March 15, 2017

Filters an input sequence using a specific filter. You specify the initial conditions for this node.

A Boolean that specifies the initialization of the internal state of the node.

True | Initializes the internal state to zero. |

False | Initializes the internal state to the final state from the previous call of this node. |

This node automatically initializes the internal state to zero on the first call and runs continuously until this input is True.

This input is available only if you wire one of the following data types to **signal**:

**Default: **False

The input filter.

Structure of the filter.

Name | Value | Description |
---|---|---|

IIR Cascade 2nd Order | 0 | Uses IIR second-order filter stages. |

IIR Cascade 4th Order | 1 | Uses IIR fourth-order filter stages. |

IIR Direct | 2 | Uses the direct-form IIR filter. |

FIR | 3 | Uses the FIR filter. |

**Default: **IIR Cascade 2nd Order

Forward coefficients of the filter.

**Default: **0

Reverse coefficients of the filter.

**Default: **0

The sampling frequency in Hz.

This value must be greater than zero.

**Default: **0

The initial internal filter state. This input must be passed from the **final conditions** output of the previous call to this node to filter samples continuously.

Values of the initial internal filter state.

Error conditions that occur before this node runs.

The node responds to this input according to standard error behavior.

Standard Error Behavior

Many nodes provide an **error in** input and an **error out** output so that the node can respond to and communicate errors that occur while code is running. The value of **error in** specifies whether an error occurred before the node runs. Most nodes respond to values of **error in** in a standard, predictable way.

**Default: **No error

The final internal filter state. You can pass this output to the **initial conditions** input of the next call to this node to filter samples continuously.

Values of the final internal filter state.

Error information.

The node produces this output according to standard error behavior.

Standard Error Behavior

**error in** input and an **error out** output so that the node can respond to and communicate errors that occur while code is running. The value of **error in** specifies whether an error occurred before the node runs. Most nodes respond to values of **error in** in a standard, predictable way.

If **filter structure** is FIR, this node obtains the elements of **filtered signal** using the following equation:

${y}_{i}=\begin{array}{cc}\underset{j=0}{\overset{{N}_{b}-1}{\sum}}{b}_{j}{x}_{i-j}& \mathrm{for}(i\ge 0)\end{array}$

where

*y*is**filtered signal***N*_{b}is the number of FIR coefficients*b*_{j}is the filter coefficients

If **filter structure** is IIR Direct, this node obtains the elements of **filtered signal** using the following equation:

${y}_{i}=\begin{array}{cc}\frac{1}{{a}_{0}}\left(\underset{j=0}{\overset{{N}_{b}-1}{\sum}}{b}_{j}{x}_{i-j}-\underset{k=1}{\overset{{N}_{a}-1}{\sum}}{a}_{k}{y}_{i-k}\right)& \mathrm{for}(i\ge 0)\end{array}$

where

*y*is**filtered signal***N*_{b}is the number of**forward coefficients***b*_{j}is the**forward coefficients***N*_{a}is the number of**reverse coefficients***a*_{k}is the**reverse coefficients**

If **filter structure** is IIR Cascade 2nd Order or IIR Cascade 4th Order, this node obtains the elements of **filtered signal** with a cascade of second- or fourth-order filter stages. The output of one filter stage is the input to the next filter stage for all *N*_{s} filter stages.

**Where This Node Can Run: **

Desktop OS: Windows

FPGA: This product does not support FPGA devices