The Discrete-Time Fourier Transform (DTFT) and the Discrete Fourier Transform (DFT) - Discrete Fourier Series are both used to analyze the frequency content of discrete-time signals, but they differ in how they represent the frequency domain.
- DTFT produces a continuous frequency spectrum
- DFT provides a discrete, sampled version of that spectrum
Essentially, the DFT is a computationally efficient way to approximate the DTFT