bilinear transform
sl1 = cls2dls(sl, T) sl1 = cls2dls(sl, T, fp)
linear systems (syslin lists)
real number, the sampling period
pre-warning frequency in hertz
given sl=[A,B,C,D] (syslin list),a continuous time system
cls2dls returns the sampled system obtained by the
bilinear transform s=(2/T)*(z-1)/(z+1).