A-Weighting filter in Mathscript

[paulmw]

I am trying to implement an A-weighted filter in MathScript following the m-files found here.  My VI is attached but the filtered signal from the bilinear transformation is zero.  I don't have MATLAB and I am not sure what I am missing.

[GrantM · Accepted solution]

Hello,

There does seem to be something going on because the filter coefficients are huge.  We will investigate this, but in the meantime, try scaling your values by the sampling frequency.  Change lines 20-23 in your MathScript node to
f1 = 20.598997/Fs;
f2 = 107.65265/Fs;
f3 = 737.86223/Fs;
f4 = 12194.217/Fs;

and line 31 to
[B,A] = bilinear(NUMs,DENs,Fs/Fs);

Grant M.
Senior Software Engineer | LabVIEW MathScript | National Instruments