The discrete-time alludes to the way that the transform operates on discrete data, regularly samples whose interval has units of time. The discrete-time Fourier transform (DTFT) is a type of Fourier analysis. It is relevant to a sequence of values. The DTFT is regularly utilized to examine samples of a continuous function. The discrete-time Fourier transform of a discrete sequence of complex numbers x[n], for all integers n, is a Fourier series, which creates a periodic function of a frequency variable.