Power Theorem
The power theorem for Fourier transforms states that the inner product of two signals in the time domain equals their inner product in the frequency domain.
The inner product of two spectra
and
may
be defined as
![]() |
(B.21) |
This expression can be interpreted as the inverse Fourier transform of


![]() |
(B.22) |
By the convolution theorem (§B.7) and flip theorem (§B.8),
![]() |
(B.23) |
which at

![]() |
(B.24) |
Thus,
![]() |
(B.25) |
Next Section:
The Continuous-Time Impulse
Previous Section:
Flip Theorems