# How to plot an impulse train. # The adjustment width h should be chosen for visual effect. f:=x->2*sin(2*Pi*x) + 5*sin(2*Pi*6*x) + 9*sin(2*Pi*11*x); Fw:=inttrans[fourier](f(x),x,w);h:='h'; ApproxDirac:=x->(1/2/h)*(piecewise(x+h<0,0,1)-piecewise(x-h<0,0,1)); F:=subs(Dirac=ApproxDirac,Fw); F:=F/I: h:=0.8:plot(F,w=-23*Pi..23*Pi);