An embedded system is a combination of computer hardware and software designed for a specific function. Embedded systems might also function within a larger system. These systems can be programmable or have a fixed functionality. Embedded systems are used today to control numerous devices. For example, they're used in industrial machines, consumer electronics, agricultural and processing industry devices, automobiles, medical devices, cameras, digital watches, household appliances, airplanes, vending machines, toys and mobile devices.

While not necessarily comprehensive, The diversity of the domains and environments in which embedded systems operate. At home, embedded systems are used to control and monitor our appliances from the simple stand-alone microwave oven, washing machine, and thermostat, to the more sophisticated and sensitive security system that monitors cameras and possibly communicates with remote systems via the Internet. Embedded systems also control our vehicles from the fuel injection control to the monitoring of emissions while managing a plethora of information using visual aids to display the operation of our vehicles. In our cities, embedded systems monitor public transportation systems which are ubiquitously connected to central stations performing online scheduling of buses and trains and provide real-time updates of arrival times across all stops for all transportation lines. At the office, embedded systems handle small electronic devices such as printers, cameras, and security systems as well as lighting.

Embedded systems have the added burden of reacting quickly and efficiently to the external “analog” environment. That may include responding to the push of a button, a sensor to trigger an air bag during a collision, or the arrival of a phone call on a cell phone. Simply put, embedded systems have deadlines that can be hard or soft. Given the “hidden” nature of embedded systems, they must also react to and handle unusual conditions without the intervention of a human.

DSPs are useful in embedded systems principally for one reason; signal processing. The ability to perform complex signal processing functions in real time gives DSP the advantage over other forms of embedded processing. DSPs must respond in real time to analog signals from the environment, convert them to digital form, perform value added processing to those digital signals, and, if required, convert the processed signals back to analog form to send back out to the environment.

Examples of embedded systems
Embedded systems are used in a wide range of technologies across an array of industries. Some examples include the following:

Automobiles Modern cars commonly consist of many computers, or embedded systems, designed to perform different tasks within the vehicle. Some of these systems perform basic utility functions and others provide entertainment or user-facing functions. As modern cars become more computerized, the number of embedded systems increases. Some embedded systems in consumer vehicles include cruise control, backup sensors, suspension control, navigation systems, alarm systems and airbag systems.
Mobile phones These consist of many embedded systems, including GUI software and hardware, operating systems (OSes), cameras, microphones, and Universal Serial Bus I/O modules.
Industrial machines These contain embedded systems, such as sensors, and can be embedded systems themselves. Industrial machines often have embedded automation systems that perform specific monitoring and control functions.
Medical equipment These contain embedded systems such as sensors and control mechanisms. Medical equipment, such as industrial machines, must also be user-friendly so that human health isn't jeopardized by preventable machine mistakes. This means these systems often include a more complex OS and GUI designed for an appropriate UI.
Fitness trackers These wearable devices contain embedded systems that collect data on the user such as heart rate, blood and oxygen levels and number of steps.