I am an EE graduate and I haven't had any pre-exposure to any signal analysis and communications course (I did mostly machines, power systems and control systems(where I have known about frequency domain)). I want to start learning about communication systems, from the early radios to the modern wifis ! Where do I begin? and which text-books do you recommend. My aim is to get maximum knowledge in the minimal time! :) My ultimate aim is to have enough knowledge in communication system to be able to design appropriate communication systems for smart grids.