octave

Generates normalized A-weigthing, -weighting, octave and one-third-octave digital filters.

Description

This series of M-files generates normalized A-weigthing, C-weighting, octave and one-third-octave digital filters. These type of filters are commonly used in acoustical measurements, for example, in noise control. The implementation is based on the IEC standard for A- and C-weighting filters and on the ANSI and IEC standards for octave and one-third-octave filters. A complete one-third-octave analyzer with graphical output is also provided.

• Acknowledgements: This submission has inspired the following:; Reverberation Time Calculator, Real time octave analysis, One-third-octave filter bank, including additional inputs and outputs, Calibrated Spectral Analysis, Nth_Oct_Hand_Arm_&_AC_Filter_Tool_Box
• MATLAB release: MATLAB 5.2 (R10)

[Boyko Stoimenov]

Great tool! I use it everyday in my research. Thanks.

[Scott Hirsch]

This is a great toolbox - I really like that it cites the ANSII standards. I tell all of my acoustics friends about it!

[William Murphy]

An excellent tool for doing octave and third octave band analysis. We are using it for analyzing different types of noise recordings that are collected in field studies. It provides a means to tranlate FFT transfer functions to more comprehensible data for the layperson.

[William Murphy]

An excellent tool for doing octave and third octave band analysis. We are using it for analyzing different types of noise recordings that are collected in field studies. It provides a means to tranlate FFT transfer functions to more comprehensible data for the layperson.

Its really a useful tool. Great!

[Boyko Stoimenov]

BUG Warning!!
It seems this submission is growing in popularity with about 2000 downloads now, and is being used by other subimissions too (Scott Hirsch's 'Real time octave analysis'). Some time ago I found a bug in the 'Leq.m' function which is also used by 'filtbank.m'. Here are the comments from my m-file:

% Leq in decibels is calculated as
% 10*log10(Prms.^2/Pref.^2)
% In the code Prms.^2 is calculated as
% p(i) = sum(x((i-1)*t+1:i*t).^2)/t;
% which is correct, but
% in the next code block Leq is calculated in dB as
% p(idx) = 10*log10(p(idx)/Pref);
% which is correct only for reference Pref=1 (1.^2 = 1)
% For Pref~=1 the code should be
% p(idx) = 10*log10(p(idx)/Pref.^2)

[Jorge Higuera]

excellent for learning DSP

[Diego Andrés]

Perfect for acoustics. I use it every day!

[Herb Singleton]

Note: if you're trying to run adsgn.m or cdsgn.m under GNU Octave (with Matcompat or Octave-forge), the line

[B,A] = bilinear(NUMs,DENs,Fs);

Should be changed to

[B,A] = bilinear(NUMs,DENs,1/Fs);

to account for Octave's syntax.

[Sreeram Shenoy]

hey too good...solved a major problem for us...thanks a ton

[Ganesh shenai]

good work man.... thanks

[Rick Stauf]

These routines helped make wind tunnel test successful.

[Marie-Hélène Lavoie]

Excellent... save me many hours of coding
Bravo

[Kjell Groendahl]

Great! Saved a lot of coding and reading in standards. Why not include these in the signal processing toolbox?

[Brian Gygi]

 

[Dilman de la Fuente]

Fantastic...i can't stop using it, and Boyco...you couldn't be more right...thanks

[Irinejus Marmakas]

 

[Jim Nicholson]

Christophe provides easy to use code of great practical value. Anyone working in acoustics should be aware of this work.

[prem shankar]

 

[Michiel Heyns]

I tested the 1/3rd octave algorithm with several sine waves and found it more than accurate anough for analysis. Thank you.

[Erich Everbach]

Thanks for this excellent tool.

[Reuben Hale]

CLean accurate and well documented

[Sunil Fernandes]

Thank you much for this.