aubio 0.4.9
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c_weighting.h File Reference

C-weighting filter coefficients. More...

Go to the source code of this file.

Functions

aubio_filter_tnew_aubio_filter_c_weighting (uint_t samplerate)
 create new C-design filter
 
uint_t aubio_filter_set_c_weighting (aubio_filter_t *f, uint_t samplerate)
 set feedback and feedforward coefficients of a C-weighting filter
 

Detailed Description

C-weighting filter coefficients.

This file creates a C-weighting digital filter, which reduces low and high frequencies and enhance the middle ones to reflect the ability of the human hearing.

The implementation is based on the following standard:

  • IEC/CD 1672: Electroacoustics-Sound Level Meters, IEC, Geneva, Nov. 1996, for A- and C-weighting filters.

See also:

The coefficients in this file have been computed using Christophe Couvreur's scripts in octave 3.0 (debian package 1:3.0.5-6+b2 with octave-signal 1.0.9-1+b1 on i386), with

 [b, a] = cdsign(1/Fs) 

for various sampling frequencies (8000, 11025, 16000, 22050, 24000, 32000, 44100, 48000, 88200, 96000, and 192000 Hz).

The sampling frequency should normally be higher than 20kHz, but most common file sampling rates have been included for completeness.

Definition in file c_weighting.h.

Function Documentation

◆ aubio_filter_set_c_weighting()

uint_t aubio_filter_set_c_weighting ( aubio_filter_t * f,
uint_t samplerate )

set feedback and feedforward coefficients of a C-weighting filter

Parameters
ffilter object to get coefficients from
sampleratesampling frequency of the signal to filter. Should be one of 8000, 11025, 16000, 22050, 24000, 32000, 44100, 48000, 88200, 96000, and 192000 Hz
Examples
temporal/test-c_weighting.c, and temporal/test-filter.c.

◆ new_aubio_filter_c_weighting()

aubio_filter_t * new_aubio_filter_c_weighting ( uint_t samplerate)

create new C-design filter

Parameters
sampleratesampling frequency of the signal to filter. Should be one of 8000, 11025, 16000, 22050, 24000, 32000, 44100, 48000, 88200, 96000, and 192000 Hz
Returns
a new filter object
Examples
temporal/test-c_weighting.c, and temporal/test-filter.c.