Software Design Considerations for Real-Time DSP Systems
This chapter outlines the requirements, issues, and design methodologies required for building a real-time digital signal processing (DSP) application. There are two types of real-time systems: reactive and embedded. A reactive real-time system involves a system that has constant interaction with its environment. An embedded real-time system is used to control specialized hardware that is installed within a larger system. The framework of real-time applications is based on fundamental infrastructure — typically an operating system (OS). OS must have certain properties to qualify it as a real-time operating system (RTOS). An RTOS requires functionality to effectively perform its functions, that is, to be able to execute all of its tasks without violating specified timing constraints. The chapter describes the major functions that RTOSs perform. The RTOS scheduling policy is one of the most important features of the RTOS to consider when assessing its usefulness in a real-time application.