Well, it depends on which counter you are using. If you are using an STC counter as on the E-Series boards, you're options are limited
You could configure it for continuous pulse generation (use the Generate Pulse Train example VI) and program the raw pulse specs to be low for 98 source edges and high for 2 source edges. (Each pulse spec must be at least 2 so the pulse will have to remain high for 2 source edge durations) The only thing is, the first pulse will be generated after only 99 source edges, but it will be on track for every subsequent set of 100 edges.
If you have access to a 660x device, you can make this a little bit cleaner by doing the later on one counter and connecting this output to another counter doing triggered pulse generation. This wa
y you can use the second counter to actually generate the pulse so that you can have a consistent pulse width.
I hope this helps!
Russell
Applications Engineer
National Instruments
http://www.ni.com/support