Part of MSEE courses.
University Northeastern University, Boston, Massachusetts.
Dr Lisa Shatz. http://www.suﬀolk.edu/college/10189.html
Linear Time-invariant Systems, Fourier Analysis for Continuous-time Signals and systems, Fourier analysis for discrete-time signals and systems, Modulation, Sampling, Laplace transform, Z-transform.
Signals And Systems By Alan V. Oppenheim, Alan S. Willsky.