tomwalters@0: % method of class @signal
tomwalters@0: % function sig=generaterampsinus(sig,carfre,modfre,amplitude,halflife)
tomwalters@0: %   INPUT VALUES:
tomwalters@0: %       sig: original @signal with length and samplerate 
tomwalters@0: %       carfre: carrier frequency (Hz) [1000]
tomwalters@0: %       modfre: modulation frequency (Hz) [100]
tomwalters@0: %       amplitude: [1]
tomwalters@0: %       halflife: time for the envelope envelope to rise exponentially
tomwalters@0: %       to 1/2
tomwalters@0: % 
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: 
tomwalters@0: function sig=generaterampsinus(sig,carfre,modfre,amplitude,halflife)
tomwalters@0: 
tomwalters@0: if nargin < 5
tomwalters@0:     halflife=0.01;
tomwalters@0: end
tomwalters@0: if nargin < 4
tomwalters@0:     amplitude=1;
tomwalters@0: end
tomwalters@0: 
tomwalters@0: if nargin < 3
tomwalters@0:     modfre=100;
tomwalters@0: end
tomwalters@0: if nargin < 2
tomwalters@0:     carfre=1000;
tomwalters@0: end
tomwalters@0: 
tomwalters@0: 
tomwalters@0: sinus=generatesinus(sig,carfre,amplitude,0);
tomwalters@0: 
tomwalters@0: % calculate envelope and mult both
tomwalters@0: envelope=sig;
tomwalters@0: time_const=halflife/0.69314718;
tomwalters@0: 
tomwalters@0: env_vals=getvalues(envelope);
tomwalters@0: time=0;
tomwalters@0: sr=getsr(envelope);
tomwalters@0: reprate=1/modfre;
tomwalters@0: 
tomwalters@0: 
tomwalters@0: for i=1:getnrpoints(envelope);
tomwalters@0:     time=time+1/sr;
tomwalters@0:     
tomwalters@0:     env_vals(i)= exp(-(reprate-time)/time_const);
tomwalters@0:     time=mod(time,reprate);
tomwalters@0:     
tomwalters@0: end
tomwalters@0: 
tomwalters@0: envelope=setvalues(envelope,env_vals);
tomwalters@0: 
tomwalters@0: sig=sinus*envelope;
tomwalters@0: % sig=sig*amplitude;
tomwalters@0: 
tomwalters@0: sig=setname(sig,sprintf('Ramp Sinus %4.2f kHz, Modulation=%4.2f Hz, halflife=%4.2f ms',carfre/1000,modfre,halflife*1000));