I'm learning Libgdx and have some questions about updating my game logic during the render method..

I would ideally like to keep my game logic and my render separate. The reason for this is if i have high FPS on a system my game loop would "run" faster.

what i am looking for is to keep the experance constant and possibily Limit my updates..if any one can point me towards a tutorial on how to 
a)Limit my render updates via DeltaTime
b)Limit my game logic updates via Deltatime.

Thank you :)