Patent ID: 7653137

Claim:
A method for temporal inversion of a wave corresponding to at least one initial signal s(t), where t is the time, this initial signal s(t) exhibiting a certain central frequency f0 and a passband Δf, in which method a temporal inversion signal α·s(−t), where α is a multiplicative coefficient and s(−t) is the temporal inversion of s(t), is determined, comprising: providing a first transformation that is applied to the initial signal s(t) for lowering the central frequency of the initial signal and for substantially not causing any loss of information with respect to the initial signal, said first transformation producing a first set of transformed signals Ki(t) comprising at least one first transformed signal Ki(t) of lower central frequency than the initial signal, said first set of transformed signals Ki(t) being representative of said initial signal s(t), providing a second transformation that is applied to each first transformed signal Ki(t) to produce a second transformed signal K′i(t) substantially of the same central frequency as the first transformed signal Ki(t), said second transformation thus producing a second set of transformed signals K′i(t) from the first set of transformed signals Ki(t), said second transformation being chosen so that said second set of transformed signals K′i(t) is representative of the temporal inversion signal s(−t), and providing a third transformation that is applied to the second set of transformed signals K′i(t) which generates the temporal inversion signal α·s(−t), wherein said steps of providing a first transformation, providing a second transformation and providing a third transformation are implemented by a device for transmitting and receiving waves.