 Parseval–Gutzmer formula

The Parseval–Gutzmer formula is an important result in the field of harmonic analysis and signal processing. It provides a relationship between the energy of a signal in the time domain and the energy of its Fourier transform in the frequency domain. This is a generalization of Parseval's theorem. The formula is typically used in the context of Fourier series or Fourier transforms and can be expressed mathematically.