Subject: Re: Filter: definition
From: Philippe-Aubert Gauthier (Philippe-Aubert.Gauthier@USherbrooke.ca)
Date: Sun Jun 19 2005 - 09:18:58 EDT
"Amplitude" should be developped a little.
A very math modification would be:
"A processor that modifies complex amplitude in a frequency dependant method."
Here "complex" (that is the gain is complex including the imaginary number) is
introduced to take into account both amplitude and phase modification. So that
a less crude modification would be:
"A processor that modifies an input both amplitude (or gain) and phase in a
frequency dependant method."
The phase is quite important, since many audio filters (for reverberation,
physical models, etc.) are often using "all-pass" filter which introduce no
amplitude modification, only phase changes. Moreover, most of the real time EQ
filters are changing the signals phases.
Selon Kevin Austin <firstname.lastname@example.org>:
> A recent discussion I have had is around a (simplified) definition of a
> The proposed version (to date) is:
> A processor that modifies amplitude in a frequency dependent method.
> (A frequency dependent amplifier.)
> Comments / pros - cons / additions etc etc??
% Philippe-Aubert Gauthier, ing. jr , M.Sc. %
% Étudiant au doctorat en reproduction de champs acoustiques %
% GAUS (Groupe d'Acoustique et de vibrations de l'Université de %
% [ Sherbrooke) %
% CIRMMT (Centre for Interdisciplinary research in Music, Media %
% [ and Technology) %
% http://www3.sympatico.ca/philippe_aubert_gauthier/acoustics.html %
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