A method for focusing broadband acoustic signals with flat spectral
content based on Time-Reversed Acoustics (TRA) principle is disclosed.
The method of the invention differs from the conventional TRA focusing in
that it includes an additional step of adjusting the spectral content of
time-reversed signal, prior to applying it to the radiating transducer.
This additional step, which includes attenuation of the spectral
components with high amplitude and amplification of the spectral
components with low amplitude, leads to flattening of the spectra of the
radiated signal and widening of its frequency band. TRA focusing with
this additional step of adjusting spectral content of the radiated signal
allows generation of shorter pulses and provides better concentration of
acoustic energy than standard TRA focusing.