**Summary:**

This tool is based upon the Audio BiQuad Cookbook Here:

http://www.musicdsp.org/files/Audio-EQ-Cookbook.txt

Very useful for configuring the FRDM-JAM and the MonkeyJam software!

# Requirements:

You need a machine with the .net 4.0 Framework (or greater) Installed (Windows 7 or Greater). If you have issues go here:

Download Microsoft .NET Framework 4 (Standalone Installer) from Official Microsoft Download Center

# Instructions:

Please report any problems in the comments section

**Original Attachment has been moved to: BiQuadFilterView---1.0.0.zip**

Hello Eli!

Thanks for this and other wonderful contributions to the community!

I am trying to implement CMSIS - Biquad Cascade IIR Filters Using Direct Form I Structure in my code and I am trying to calculate the coefficients using your tool. In the "http://www.musicdsp.org/files/Audio-EQ-Cookbook.txt" file, the equation is as follows:

y[n] = (b0/a0)*x[n] + (b1/a0)*x[n-1] + (b2/a0)*x[n-2] - (a1/a0)*y[n-1] - (a2/a0)*y[n-2]

However, in the BiQuadFilterView program of yours, in the info area, I can see that the equation is as follows:

y[n] = b[0]*x[n] + b[1]*x[n-1] + b[2]*x[n-2] - a[1]*x[n-1] - a[1]*y[n-2]

In the Keil CMSIS documentation, the equation is as follows:

y[n] = b0 * x[n] + b1 * x[n-1] + b2 * x[n-2] + a1 * y[n-1] + a2 * y[n-2]

Notice the difference in between -a[1]*x[n-1] - a[1]*y[n-2] and + a1 * y[n-1] + a2 * y[n-2].

Is this a typo or the BiQuadFilterView uses a different algorithm?