ABSTRACT
The spectral power at each frequency is given by the Fourier transforms of equations (96) and (97). In the simple case where the noise n(xj, t) has the same spectrum at each point xj,
and the spectrum of pj is
This shows that random components will contribute to the presumed spectrum of waves moving in the + and - directions. This is the disadvantage of using a
2-D Fourier transform: since everything looks like a propagating wave, there is no capacity for distinguishing between noiselike random phenomena and true propagating waves. Yet these noiselike features are a common-if not omnipresent-feature of the state of the real world.
