annotate aim-mat/tools/@signal/attenuate.asv @ 4:537f939baef0 tip

various bug fixes and changed copyright message

% method of class @signal
% 
%   INPUT VALUES:
%  sig,attenuation
% sig is the signal
% attenuation is the attenuation against the lowdest possible tone
% 
% 
%
%   RETURN VALUE:
%
% 
% (c) 2003, University of Cambridge, Medical Research Council 
% Stefan Bleeck ([e-mail])
% http://www.mrc-cbu.cam.ac.uk/cnbh/aimmanual
% $Date: 2003/06/11 10:46:32 $
% $Revision: 1.1 $



function sig=attenuate(sig,attenuation)

if attenuation==0
    return
end

dat=sig.werte;
ma=max(dat);
mi=min(dat);
if -mi > ma
    ma=-mi;
end


amphigh=max(sig);

amp=amphigh / power(10,-attenuation/20);
if amp>0
    sig=scaletomaxvalue(sig,amp);
end