//// Generation of Poisson spike train with refractoriness
 clear; clf;   
 fr_mean=15/1000;      // mean firing rate per ms
//// generating poisson spike train
 lambda=1/fr_mean;              // time interval/firing rate in interval
 ns=1000;                       // number of spikes to be generated
 isi1=-lambda.*log(rand(ns,1)); // generation of exponential distr. ISIs
//// Delete spikes that are within refractory period
 is=0;
 for i=1:ns;
     if rand() > exp(-isi1(i)^2/32);  
         is=is+1;
         isi(is)=isi1(i);
     end
 end
//// Ploting histogram and caclulating cv
 histplot(50,isi);          // Plot histogram of 50 bins
 cv=st_deviation(isi)/mean(isi)  // coefficient of variation