It gives me immense satisfaction in presenting this book to my students who have been eagerly waiting to see it. The difficulties encountered by students in understanding the physical significance of different concepts inspired me to write a student-friendly book, rich in technical content. The subject Signals and Systems is essential for undergraduate students of Electronics Engineering, Electrical Engineering, Computer Engineering, and Instrumentation Engineering disciplines. The subject has a diverse range of applications. A thorough knowledge of different transforms studied in Mathematics is essential for an understanding of the subject.

The subject involves a number of complex algorithms which require indepth domain knowledge. If a concept is explained with concrete examples and programs, the reader will definitely take interest in the field. The reader will experience great joy when she observes tangible outcomes of an experiment on her computer screen. A number of signals occurring in nature like speech, ECG, EEG etc. have some random components. Research in this field is somewhat difficult. Despite significant progress in an understanding of the subject, there remain many things which are not well grasped. There is room for explaining the basic concepts of signals and systems, in a better manner. Different concepts are illustrated here using MATLAB programs. The outputs of the MATLAB programs are given in the form of graphs. With extensive experience in signals and systems research, I observed, that people require significant amount of time before they can begin grasping the subject. However with proper guidance, a person can acquire considerable knowledge in this field. The motivation behind this book has been, that a new comer be provided information about where and how to start and how to proceed.

There was a request from my students as well as from well wishers that I write a book on signals and systems. It was also suggested that the book include the theory of random signals. Several concrete examples have been given to illustrate the concepts pertaining to random signals. For better understanding, we have included output from many MATLAB programs. Interpretations of the results are also explained, which will not only help the reader but also enable instructors to incorporate the examples into their classroom teaching.