Hi Nick,
There are various ways to develop a pulse train, I have attached a link below which gives you an idea how you could do it with our products.
http://zone.ni.com/devzone/conceptd.nsf/webmain/D2757CFF47D694F686256802007B8B32?opendocument
Hope this helps.
Best Regards
Atul Wahi
www.ni.com