Learn more about Signal Processing Toolbox

Overview

On this page…
Introduction to FDA Tool Integrated Products Filter Design Methods Using the Filter Design and Analysis Tool Analyzing Filter Responses Filter Design and Analysis Tool Panels Getting Help

Introduction to FDA Tool

The Filter Design and Analysis Tool (FDATool) is a powerful user interface for designing and analyzing filters quickly. FDATool enables you to design digital FIR or IIR filters by setting filter specifications, by importing filters from your MATLAB workspace, or by adding, moving or deleting poles and zeros. FDATool also provides tools for analyzing filters, such as magnitude and phase response and pole-zero plots.

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Integrated Products

FDATool seamlessly integrates additional functionality from other MathWorks™ products as described in the following table.

Product	Added Features
TI's C2000™	Download code to TI's C2000 DSP target board
Filter Design HDL Coder™	Generate synthesizable VHDL or Verilog for fixed-point filters
Filter Design Toolbox	Advanced FIR and IIR design techniques (see Advanced Filter Design Methods) Filter transformations Multirate filters Fixed-point filters (available only with Simulink® Fixed Point™ product)
Embedded IDE Link™	Export code usable by Code Composer Studio™ software
Signal Processing Blockset	Generate equivalent Signal Processing Blockset™ block for the filter
Simulink	Generate filters from atomic Simulink blocks

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Filter Design Methods

FDATool gives you access to the following Signal Processing Toolbox filter design methods.

Design Method	Function
Butterworth	butter
Chebyshev Type I	cheby1
Chebyshev Type II	cheby2
Elliptic	ellip
Maximally Flat	maxflat
Equiripple	firpm
Least-squares	firls
Constrained least-squares	fircls
Complex equiripple	cfirpm
Window	fir1

When using the window method in FDATool, all Signal Processing Toolbox window functions are available, and you can specify a user-defined window by entering its function name and input parameter.

Advanced Filter Design Methods

The following advanced filter design methods are available if you have Filter Design Toolbox product installed.

Design Method	Function
Constrained equiripple FIR	firceqrip
Constrained-band equiripple FIR	fircband
Generalized remez FIR	firgr
Equripple halfband FIR	firhalfband
Least P-norm optimal FIR	firlpnorm
Equiripple Nyquist FIR	firnyquist
Interpolated FIR	ifir
IIR comb notching or peaking	iircomb
Allpass filter (given group delay)	iirgrpdelay
Least P-norm optimal IIR	iirlpnorm
Constrained least P-norm IIR	iirlpnormc
Second-order IIR notch	iirnotch
Second-order IIR peaking (resonator)	iirpeak

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Using the Filter Design and Analysis Tool

There are different ways that you can design filters using the Filter Design and Analysis Tool. For example:

• You can first choose a response type, such as bandpass, and then choose from the available FIR or IIR filter design methods.

• You can specify the filter by its type alone, along with certain frequency- or time-domain specifications such as passband frequencies and stopband frequencies. The filter you design is then computed using the default filter design method and filter order.

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Analyzing Filter Responses

Once you have designed your filter, you can display the filter coefficients and detailed filter information, export the coefficients to the MATLAB workspace, and create a C header file containing the coefficients, and analyze different filter responses in FDATool or in a separate Filter Visualization Tool (fvtool). The following filter responses are available:

• Magnitude response (freqz)

• Phase response (phasez)

• Group delay (grpdelay)

• Phase delay (phasedelay)

• Impulse response (impz)

• Step response (stepz)

• Pole-zero plots (zplane)

• Zero-phase response (zerophase)

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Filter Design and Analysis Tool Panels

The Filter Design and Analysis Tool has sidebar buttons that display particular panels in the lower half of the tool. The panels are

• Design Filter. See Choosing a Filter Design Method for more information. You use this panel to

  • Design filters from scratch.

  • Modify existing filters designed in FDATool.

  • Analyze filters.

• Import filter. See Importing a Filter Design for more information. You use this panel to

  • Import previously saved filters or filter coefficients that you have stored in the MATLAB workspace.

  • Analyze imported filters.

• Pole/Zero Editor. See Editing the Filter Using the Pole/Zero Editor. You use this panel to add, delete, and move poles and zeros in your filter design.

If you also have Filter Design Toolbox product installed, additional panels are available:

• Set quantization parameters — Use this panel to quantize double-precision filters that you design in FDATool, quantize double-precision filters that you import into FDATool, and analyze quantized filters.

• Transform filter — Use this panel to change a filter from one response type to another.

• Multirate filter design — Use this panel to create a multirate filter from your existing FIR design, create CIC filters, and linear and hold interpolators.

If you have Simulink installed, this panel is available:

• Realize Model — Use this panel to create a Simulink block containing the filter structure. See Exporting to a Simulink Model for more information.

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Getting Help

At any time, you can right-click or click the What's this? button, , to get information on the different parts of the tool. You can also use the Help menu to see complete Help information.

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FDATool: A Filter Design and Analysis GUI

Opening FDATool

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