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Cascade To Direct Coefficients VI

LabVIEW 2013 Help

Edition Date: June 2013

Part Number: 371361K-01

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Owning Palette: Advanced IIR Filtering VIs

Requires: Full Development System

Converts IIR filter coefficients from the cascade form to the direct form.


IIR Filter Cluster contains the cascaded form of IIR filter coefficients. This cluster is the output from one of the IIR coefficient design VIs: Butterworth Coefficients, Bessel Coefficients, Chebyshev Coefficients, Elliptic Coefficients, or Inv Chebyshev Coefficients.
filter structure selects IIR second-order or fourth-order filter stages.

0IIR 2nd Order
1IIR 4th Order
Reverse Coefficients is the reverse coefficients of the IIR cascade filter.
Forward Coefficients is the forward coefficients of the IIR cascade filter.
Reverse Coefficients contains the direct-form, reverse coefficients.
Forward Coefficients contains the direct-form, forward coefficients.

Cascade To Direct Coefficients Details

As an example, you can convert a cascade filter, composed of two second-order stages, to a direct-form filter as follows.

Reverse Coefficients

{a11, a12, a21, a22} {1.0, a1, a2, a3, a4}

Forward Coefficients

{b01, b11, b02, b12, b22} {b0, b1, b2, b3, b4}

Refer to the IIR Cascade Filter VI for more information about cascade-form filtering and the IIR Filter VI for more information about direct-form filtering.


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