This video introduces the key principles and concepts that will be considered in the signal analysis part of the Sensor Network and Data Analysis (SNADA) course. It discusses the importance of linear system modelling, complex phasors, signal decompositions, and sampling theory. The video then introduces the first key principle, which is on basic sampling techniques. Nyquist's sampling theorem is mentioned, but understanding the origin of this theorem is crucial to understanding its limitations, and how it is possible to beat Nyquist.