To find frequency range of a signal that changes over time

The Fourier Transform is a mathematical operation that transforms a signal from its original domain (usually time or space) to the frequency domain. In the context of deep learning, the Fourier Transform is not directly used as a layer within neural networks, but it can be a preprocessing step or a component in certain applications. Here are some ways in which the Fourier Transform is relevant to deep learning (but not limited to):

Dear Doctor

"It helps extract frequency-domain information, which can be valuable for certain tasks. For example, in speech recognition, the Fourier Transform can be used to analyze the frequency components of audio signals."

Here you can find the complete details in keras official documentation https://keras.io/api/ops/fft/