This unit introduces concepts of continuous-time and discrete-time signals, their sampling and aliasing issues. Complex numbers, in particular, complex exponentials are introduced along with their representation as phasors, leading to periodic waveforms, Fourier series and the signal frequency spectrum. Modification of spectra will be described using FIR and IIR filters, discrete-time systems, the unit-sample response, linear time-invariant systems, the continuous-time Fourier transform, windowing, DFT, FFT, time-frequency spectrum analysis, spectrogram and Laplace Transform. |