  A new look at the so-called effect of an accelerating matter is presented. It
was previously stated that the effect is optical in nature and consists in
changing the frequency of the wave passing through a refractive sample moving
with acceleration. However, from a simple consideration based on the principle
of equivalence, it follows that the idea of the connection of the effect only
with the refraction phenomenon is unreasonably narrow, and a change in the wave
frequency should inevitably occur during scattering by any object moving with
acceleration. Such an object can be either an elementary scatterer or any
device transmitting a narrowband signal.
