Study of convolution: series and parallel system 
References
Books
- Digital Principles and Applications, by Leach and Malvino.
- Digital Logic Design, Leach, by Malvino, and Saha
- Engineering Digital Design, by Richard F. Tinder.
- Digital Logic and Computer Design, by M. Morris Mano
- Digital Systems: Principles and Applications, Neal S. Widmer , Ronald J. Tocci , Gregory L. Moss