Overview

The processing of electrical signals is the fundamental means by which portable electronic devices accomplish their desired functionality. System inputs are received from a variety of sources including the product user, electronic sensors, external devices, and external networks. These inputs are processed and the desired output is achieved through the appropriate output device.

The silicon integrated circuit (IC) is the fundamental technology that has enabled electronic processing capabilities for portable electronic products. Processing is achieved through the system electronics, which consist of integrated circuits and other electronic components mounted to a printed circuit board. The designer of a portable electronic device need not be an expert designer of integrated circuits or printed circuit boards. The portable electronic product designer must be knowledgeable in the high-level architecture of these systems and able to drive the selection of off-the-shelf components that will result in a successful system implementation. Custom integrated circuits may also be needed in many applications and the product designer should be familiar with the options available for creating unique electronic functionality.

Much of the processing that occurs in portable electronic devices takes place in the digital domain where microprocessor and digital signal processing (DSP) principles are implemented. Custom logic devices are frequently used to tie together various functions in a digital processing system. System-on-chip (SOC) devices are exploited to reduce the amount of custom design required to integrate a complex digital processing system.

The real world, however, is made up of analog signals. Sounds, images, scents, and...