ScopeIIR

ScopeIIR is a lightweight software application developed specifically for helping you design IIR filters based on the Butterworth, Chebyshev, or Elliptic analog prototypes. The tool is able to produce lowpass, highpass, bandpass, and bandstop filters, with configurable frequency and gain characteristics.

Interacting with the GUI

The user interface looks clean and reveals a well-organized suite of features. However, the program comes with support for lots of configuration parameters so it may be a good idea to invest some extra time into experimenting with its functions.
You may also appeal to a help manual in case you want to find out more about the utility’s comprehensive IIR filter designing capabilities.

Analysis tools

ScopeIIR gives you the possibility to work with various plots in order to visualize and explore the characteristics of your filter design.
The application works with frequency response plots (magnitude, phase, unwrapped phase, group delay, phase delay), time response plots (impulse response, step response, and combined impulse and step response), data displays (biquad coefficients, direct form coefficients, poles and zeros, design specification, impulse response, step response), as well as Pole-Zero plot (which helps with making detailed adjustments to the filter characteristics).
You are allowed to make use of an advanced set of data file outputs in order to employ the filters in your system, more specifically biquad coefficients (the tool automatically groups together poles and zeros), direct form coefficient, poles and zeros, design specifications, impulse response, and step response. Each output item can be exported to plain text, C, C++, and MATLAB file format.
ScopeIIR lets you print the information, save a project to a file on your computer so you can import data in the future, set the sampling frequency, configure the minimum dB (decibels), as well as undo or redo your actions.
Tests have shown that the program carries out a task quickly and without errors. It does not eat up a lot of CPU and memory resources so the overall performance of the computer is not hampered.

Bottom line

All things considered, ScopeIIR provides a comprehensive suite of features for helping you design, analyze, and implement IIR filters, and is suitable especially for professionals.