tomwalters@0: % tool
tomwalters@0: % 
tomwalters@0: %   INPUT VALUES:
tomwalters@0: %  
tomwalters@0: %   RETURN VALUE:
tomwalters@0: %
tomwalters@0: % 
bleeck@3: % This external file is included as part of the 'aim-mat' distribution package
bleeck@3: % (c) 2011, University of Southampton
bleeck@3: % Maintained by Stefan Bleeck (bleeck@gmail.com)
bleeck@3: % download of current version is on the soundsoftware site: 
bleeck@3: % http://code.soundsoftware.ac.uk/projects/aimmat
bleeck@3: % documentation and everything is on http://www.acousticscale.org
bleeck@3: 
tomwalters@0: 
tomwalters@0: function ampscale=filterbandamp(fre,amp,fc,df1,bw,df2)
tomwalters@0: % usage: ampscale=filterbandamp(fre,amp,fc,df1,bw,df2)
tomwalters@0: % given a frequency and its associated amplitude, and the defining properties of
tomwalters@0: % a bandpass filter (cf. Krumbholz et al (2000), JASA 108, 1170-1180, Fig.3)
tomwalters@0: % this function returns the amplitude of the frequency component after it has
tomwalters@0: % passed through the filter. The reurned amplitude should be used to SCALE the
tomwalters@0: % amplitude of the given frequency component.
tomwalters@0: % fre       frequency in Hz
tomwalters@0: % amp       amplitude 
tomwalters@0: % fc        lower cutoff frequency
tomwalters@0: % df1       lower spectral ramp width
tomwalters@0: % bw        bandwidth (of plateau)
tomwalters@0: % df2       upper spectral ramp
tomwalters@0: %
tomwalters@0: % David Smith (16/05/02)
tomwalters@0: 
tomwalters@0: if (fre<(fc-df1)) | (fre>(fc+bw+df2))
tomwalters@0:     ampscale=0; %ignore everything outside passband
tomwalters@0: elseif fre<=fc  %lower spectral ramp
tomwalters@0:     ampscale=max(cos((fc-fre)*pi/(2*df1)),0);   %quarter-cycle of cosine function
tomwalters@0: elseif fre<=fc+bw    %flat part of filter
tomwalters@0:     ampscale=1; 
tomwalters@0: else        %upper spectral ramp
tomwalters@0:     ampscale=max(cos((fre-(fc+bw))*pi/(2*df2)),0);
tomwalters@0: end