A decoder is an electronic device or software that converts encoded data back into its original format. It is commonly used in various applications, such as telecommunications, where it helps to interpret signals and retrieve information. For example, in digital television, a decoder translates compressed video and audio signals into a format that can be displayed on a screen. In computer science, decoders are often used in data processing and communication systems. They can take binary input and produce a specific output based on that input. This function is essential in devices like microcontrollers and digital circuits, where accurate data interpretation is crucial for proper operation.