Signal Processing Toolbox

Overview of the Filter Designer: Filter Design

The Filter Designer provides an interactive graphical environment for the design of digital IIR and FIR filters based on specifications that you enter on a magnitude or pole-zero plot.

Note    You can also use the Filter Design and Analysis Tool (FDATool) described in Chapter 5, "Filter Design and Analysis Tool, for filter design and analysis.

Filter Types

You can design filters of the following types using the Filter Designer:

• Bandpass
• Lowpass
• Bandstop
• Highpass

FIR Filter Methods

You can use the following filter methods to design FIR filters:

• Equiripple
• Least squares
• Window

IIR Filter Methods

You can use the following filter methods to design IIR filters:

• Butterworth
• Chebyshev type I
• Chebyshev type II
• Elliptic

Pole/Zero Editor

You can use the Pole/Zero Editor to design arbitrary FIR and IIR filters by placing and moving poles and zeros on the complex z-plane.

Spectral Overlay Feature

You can also superimpose spectra on a filter's magnitude response to see if the filtering requirements are met.

Opening the Filter Designer

Open the Filter Designer from SPTool by either:

• Pressing the New Design button in the Filters list in SPTool
• Selecting a filter you want to edit from the Filters list in SPTool, and then pressing the Edit Design button
  
  

The Filter Designer has the following components:

• A menu for selecting filters from the list in SPTool
• A menu for selecting different filter design methods (algorithms)
• A plot display region for graphically adjusting filter magnitude responses
• Measurement lines for measuring the magnitude response parameters of a filter
• A pole-zero plot display region for graphically editing filter designs by manipulating transfer function poles and zeros
• Zoom buttons for navigating the displays
• A Specifications region for viewing and modifying the design parameters or pole-zero locations of the current filter
• A Measurements region for viewing the response characteristics and stability of the current filter

Overview of the Signal Browser: Signal Analysis

Overview of the Filter Viewer: Filter Analysis