Major purpose of this lecture is to presentation on Analog form to Digital Domain. When something is completed in the electronic digital domain, it signifies that the original files, example: images, sounds, video, etc. has been converted into searching for format and is manipulated inside computer’s memory. This lecture also briefly describe on Analog vs. digital: why, what & how it is done and its systems. Other objectives are to focus on Digital system example, Sampling & aliasing and ADCs: performance & choice. Finally briefly present digital data formats.