Discrete Time Transformations: DTFS and DTFT
In the subsequent chapters we are going to discuss about the discrete signal conditioning including related transformations both in single dimensional (1D) and two dimensional (2D) signals. The present chapter would emphasize on the fundamental frequency domain representations in discrete time domain. Fourier series and transform would be here illustrated for discrete time signals. They will be named as Discrete Time Fourier Series (DTFS) and Discrete Time Fourier Transform (DTFT), for sampled periodic and non-periodic signals (or sequences) respectively. The process of sampling, properties of its spectra, aliasing, concept of analog and digital frequencies and their mathematical relationships are discussed in a non-conventional way mostly using "convolution".