The purpose of the requirements definition phase is to produce a clear, complete, consistent, and testable 71 of the technical requirements for the software product.
During the requirements definition phase, the requirements definition team uses an iterative process to expand a broad statement of the system requirements into a complete and detailed specification of each function that the software must perform and each 72 that it must meet. The starting point is usually a set of high-level requirements from the 73 that describe the project or problem.
In either case, the requirements definition team formulates an overall concept for the system and the defines 74 showing how the system will be operated, publishes the system and operation concept documents, and conducts a system concept review (SCR).
Following the SCR, the team derives 75 requirements for the system from the highlevel requirements and the system operations concept. Using structured or object-oriented analysis,the team specifies the software functions and algorithms needed to satisfy each detailed requirements.