Vedantic meditation is when the object of meditation is the subject itself, my own reality, the Atman. In Patanjali yoga, the practice is to is Yogas Chittavriti Nirodaha. The mind is constantly being transformed into various modifications. Ripples are coming up on the surface of the lake of the mind. So to calm it down, to make it one-pointed, not to put it to sleep. There is a difference between going to sleep and becoming one-pointing.