Contents

Digital Filter Design

Design and implement digital FIR and IIR filters

Library

Filtering / Filter Implementations

dsparch4

Description

    Note:   Use this block to design, analyze, and efficiently implement floating-point filters. The following blocks also implement digital filters, but serve slightly different purposes:

    • Discrete FIR Filter and Biquad Filter— Use to efficiently implement floating-point or fixed-point filters that you have already designed. These blocks provide the same exact filter implementation as the Digital Filter Design block.

    • Filter Realization Wizard — Use to implement floating-point or fixed-point filters built from Sum, Gain, and Unit Delay blocks. You can either design the filter within this block, or import the coefficients of a filter that you designed elsewhere.

The Digital Filter Design block implements a digital FIR or IIR filter that you design using the Filter Design and Analysis Tool (fdatool) GUI. This block provides the same filter implementation as the Discrete FIR Filter or Biquad Filter blocks.

You must specify whether the block performs frame-based or sample-based processing on the input by setting the Input processing parameter. The block applies the specified filter to each channel of a discrete-time input signal, and outputs the result. The outputs of the block numerically match the outputs of the Discrete FIR Filter or Biquad Filter block, the MATLAB® filter function, and the DSP System Toolbox™ filter function.

The sampling frequency, Fs, that you specify in the FDATool GUI should be identical to the sampling frequency of the input to the Digital Filter Design block. When the sampling frequencies do not match, the Digital Filter Design block returns a warning message and inherits the sampling frequency of the input block.

Designing the Filter

Double-click the Digital Filter Design block to open FDATool. Use FDATool to design or import a digital FIR or IIR filter. To learn how to design filters with this block and FDATool, see the following topics:

Tuning the Filter During Simulation

You can tune the filter specifications in FDATool during simulations as long as your changes do not modify the filter length or filter order. The filter updates as soon as you apply any filter changes in FDATool.

Examples

See the Digital Filter Design Block section in the DSP System Toolbox documentation.

Dialog Box

For more information about the parameters on this dialog, see FDATool.

Supported Data Types

  • Double-precision floating point

  • Single-precision floating point

See Also

Discrete FIR FilterDSP System Toolbox
Biquad FilterDSP System Toolbox
Analog Filter DesignDSP System Toolbox
Window FunctionDSP System Toolbox
fdatoolDSP System Toolbox
filterDSP System Toolbox
fvtoolSignal Processing Toolbox
sptoolSignal Processing Toolbox

To learn how to use this block and FDATool, see the following:

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