IirDirectFilter Class

Measurement Studio 2019 Help

Edition Date: May 2019

Part Number: 375857B-01

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Note: This topic applies to the following Measurement Studio editions: Enterprise, Professional.

Implements a class that filters the input sequence using the direct form IIR filter specified by the reverse coefficients and forward coefficients.

Namespace: NationalInstruments.Analysis.Dsp.Filters

Assembly: NationalInstruments.Analysis.Enterprise (in NationalInstruments.Analysis.Enterprise.dll) Version: (


Visual Basic (Declaration)
<SecurityPermissionAttribute(SecurityAction.Demand, Flags := SecurityPermissionFlag.UnmanagedCode)> _
Public Class IirDirectFilter _
	Implements IFilter

[SecurityPermissionAttribute(SecurityAction.Demand, Flags = SecurityPermissionFlag.UnmanagedCode)]
public class IirDirectFilter : IFilter


Use this class if you want to provide your own reverse coefficients and forward coefficients. The input sequence is filtered using the direct form IIR filter and the reverse coefficients and forward coefficients using the following formula:

where x is the input data,
y is the filtered data,
nb is the number of forward coefficients,
bi are the forward coefficients,
na is the number of reverse coefficients, and
ai are the reverse coefficients.

The filter initialization uses the following equations:

yi = yic[na + i 1] for i <0

xi = yic[nb + i 1] for i <0

where yic is the array of initial Y conditions and xic is the array of initial X conditions.

Inheritance Hierarchy


Thread Safety

Any public static (Shared in Visual Basic) members of this type are safe for multithreaded operations. Any instance members are not guaranteed to be thread safe.

See Also


IirDirectFilter Members

NationalInstruments.Analysis.Dsp.Filters Namespace


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