Fundamentals of Touch Technologies
1.Controller innovation areas:Performance,power,cost,stylus&palm rejection,hover,gloves,water-resistance,pressure,gestures,proximity,haptics...
http://touchinternational.com/products/projected-capacitive-touch-screen/
2.PRS clock source creats less RF emission than using the same effective fixed clock frequency due to spread-spectrum operation. When using a PRS clock, the CapSense measurements are less sensitive to external noise.
https://en.wikipedia.org/wiki/Spread_spectrum