Notes on discrete-time Fourier series and transform

The following are my notes on discrete-time Fourier series (DTFS), as well as the discrete-time Fourier transform (DTFT). These topics serve as an important theoretical underpinning to the digital processing of signals by computers using the DFT (which will be covered in a future post). For discrete-time signals, we use the square bracket notation to denote samples: x[n] is the n-th sample of sign