Several different kinds of processors can be used in mobile phones, performing several different functions. The most common processor is the application processor, in all mobile phones the application processor is based on an ARM core. This core was developed in the UK by ARM and has been licensed to many other silicon vendors for incorporation in their mobile phone chipsets. This core is also used in many PDA's. The ARM core is probably the most common processor in the world. The ARM core offers very high performance and low power operation by virtue of it's RISC design which makes it the processor of choice in mobile phones