tomwalters@0: % method of class @signal
tomwalters@0: % function sig=genbandpassnoise(sig,varargin)
tomwalters@0: %   INPUT VALUES:
tomwalters@0: %       sig: @signal with length and samplerate 
tomwalters@0: %   RETURN VALUE:
tomwalters@0: %       sig:  @signal 
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
tomwalters@0: 
tomwalters@0: function sig=genbandpassnoise(sig,lowfrequency,highfrequency)
tomwalters@0: % steepness is given in dB per octave (to make it compatible with Fastl)
tomwalters@0: 
tomwalters@0: len=getlength(sig);
tomwalters@0: sr=getsr(sig);
tomwalters@0: 
tomwalters@0: % generate white noise:
tomwalters@0: vals=getvalues(sig);
tomwalters@0: 
tomwalters@0: nyquist_frequenz=sr/2;
tomwalters@0: N=getnrpoints(sig);
tomwalters@0: 
tomwalters@0: n1=round(lowfrequency/nyquist_frequenz*N/2);
tomwalters@0: n2=round(highfrequency/nyquist_frequenz*N/2);
tomwalters@0: 
tomwalters@0: if n1<=0
tomwalters@0:     n1=1;
tomwalters@0: end
tomwalters@0: if n2>N
tomwalters@0:     n2=N;
tomwalters@0: end
tomwalters@0: 
tomwalters@0: noise1=zeros(size(vals));
tomwalters@0: noise2=zeros(size(vals));
tomwalters@0: for i=n1:n2
tomwalters@0:     noise1(i)=rand(1);
tomwalters@0: end
tomwalters@0: for i=N-n2:N-n1
tomwalters@0:     noise2(i)=rand(1);
tomwalters@0: end
tomwalters@0: ftband=noise1+ i*noise2;
tomwalters@0: vals=ifft(ftband);
tomwalters@0: vals=real(vals);
tomwalters@0: 
tomwalters@0: sig=setvalues(sig,vals);
tomwalters@0: sig=setname(sig,sprintf('Bandpass filtered noise from %4.1f Hz to %4.1f Hz',lowfrequency,highfrequency));
tomwalters@0: 
tomwalters@0: return