The reference text discusses signal processing tools and techniques used for the design, testing, and deployment of communication systems. It further explores software simulation and modeling tools like MATLAB, GNU Octave, Mathematica, and Python for modeling, simulation, and detailed analysis leading to comprehensive insights into communication systems. The book explains topics such as source coding, pulse demodulation systems, and the principle of sampling and aliasing. This book: Discusses modern techniques including analog and digital filter design, and modulation principles including quadrature amplitude modulation, and differential phase shift keying. Covers filter design using MATLAB, system simulation using Simulink, signal processing toolbox, linear time-invariant systems, and non-linear time-variant systems. Explains important pulse keying techniques including Gaussian minimum shift keying and quadrature phase shift keying. Presents signal processing tools and techniques for communication systems design, modeling, simulation, and deployment. Illustrates topics such as software-defined radio (SDR) systems, spectrum sensing, and automated modulation sensing. The text is primarily written for senior undergraduates, graduate students, and academic researchers in the fields of electrical engineering, electronics and communication engineering, Computer Science, and engineering. In Chapter 1, we begin with a study of fundamental concepts of systems and signals and various transforms of signals and progress to the application of Digital Signal Processing tools in the design of communication subsystems. In Chapter 2, we explore software simulation and modeling tools like MATLAB, GNU Octave, Python, and Mathematica for the modeling, simulation and detailed analysis leading to comprehensive insights in Communication Systems.