IGOR Filter Design Laboratory

IGOR Filter Design Laboratory (IFDL) is a sophisticated and flexible environment for interactive design, evaluation, and application of Finite Impulse Response (FIR) and Infinite Impulse Response (IIR) digital filters.

IFDL consists of IGOR procedures and an XOP (external operation) file that you use with your IGOR experiments and your existing copy of IGOR Pro. A printed and an electronic manual are included.

IFDL 4 ships on CD-ROM, and requires IGOR Pro 4.06A or later (updaters for earlier versions of IGOR Pro 4 are included on the CD-ROM). Mac OS 8.6 or later (including Mac OS X) and Windows 95 or later are supported.

Applications of IFDL

• Designing IIR & FIR filters for use with external programs or hardware.
• Designing filters to be used within IGOR to filter your data.
• Experimenting with Digital Signal Processing (DSP) techniques.

IFDL is meant to be used by people with some knowledge of digital filters and DSP.

IFDL 4 adds the ability to design and apply Infinite Impulse Response (IIR) digital filters.

IFDL's User Interface

IFDL 4 has a substantially revised user interface that uses IGOR Pro 4's user-defined controls (push buttons, popup menus, and SetVariable controls):

The IFDL Filter Designs

IFDL can design FIR filters using the following techniques:

Kaiser's Maximum Flatness design.
Kaiser's window method.
McClellan-Parks-Rabiner equiripple method:
  arbitrary response
  bandpass
  band reject
  differentiators
  highpass
  Hilbert transformers
  lowpass
  multi-band

Window method using these standard windows:
  Hanning
  Kaiser[ß=1]
  Parzen
  Rectangular
  Welch
  (The user can easily add other windows.)

IFDL 4 can design IIR filters using a bilinear transform of classical analog filter designs:

Bessel
Butterworth.
Chebyshev.
Notch-only.

 

These new IIR filters can be implemented using a Direct Form I or Cascaded Bi-Quad Direct Form II filter.

Instant Evaluation

IFDL automatically applies the current filter design to ideal or real data you select, whenever you request it or whenever you change a filter design parameter for instant feedback on how the filter will affect the data.

Comparing Filters

IFDL graphically compares two FIR filter's frequency, impulse, and step responses.

Applying Filters

You can apply the designed filters in other experiments by importing the saved filter coefficients and combining them with your data: