square pulse train

Hello Everybody,

I am trying to make a square pulse train in Comsol without Matlab.
The train should have a period of 0.01s, but the pulse itself is just 8e-9s.
One pulse is no problem with the smooth functions (flc2hs), but how can I repeat my pulse function?
Is there any function in Comsol to do so? I found nothing.
Or has anybody another solution to this problem without using Matlab?
My pulse function is:
flc2hs(t-1e-9,1e-9)-flc2hs(t-9e-9,1e-9)

Thanks a lot and kind regards,

C.Mannal