Signals and systems is an interdisciplinary field that forms the foundation of modern communication and measurement technologies. It involves the study of both analog and digital signal processing, focusing on continuous-time and discrete-time signals in time and frequency domains. In this context, systems can be viewed as mappings or operators that transform input signals into output responses. When one or more input signals are applied, the system processes them to generate corresponding outputs, making this framework essential for analyzing and designing a wide range of engineering applications.