Actually that pdf of yours smart_storm is very poor. It's been copied from various publications and cobbled together as a 'thesis' for exam credits. Certainly read what the author says, but it is not an engineering document written by anyone with any grasp beyond copying other peoples work - and it's very old technology at that - so be careful with it. It may fool his teachers (who should know better), but not an engineer. Luciano's offering is a far better starting point.