Signal Diagram in Support of System Requirements Analysis

Abstract

System development for airborne applications benefits from structural analysis as known from software engineering for describing the architecture of the system and analyzing the flow of information. Although the Unified Modeling Language is widely accepted as a standard for requirements analyses in information technology, its application to real-time signal processing design as encountered in avionics or flight test instrumentation design is often problematic. The cause is the absence of a diagram type that is tailored to signal processing instead of classical, operator-driven use cases. A new type of diagram, referred to as the signal diagram, is introduced as an alternative to use-case modeling. The signal diagram models the complete flow of information through the application, while focussing on the information itself rather than the components by which it is created or processed. The diagram combines existing symbology from electrical, electronic, and software engineering diagrams. It is intended as the very first diagram to be created upon system development. As such, it captures system requirements on the basis of functional requirements and serves as the starting point for deriving component requirements.