Acoustical applications of modulation beamforming technology

A method for generating a spatial distribution of acoustic transmitting frequencies by a time modulated array (TMA) of transducers that produce simultaneous multiple beam steering in a non-linear propagation medium, comprising the steps of:

• generating, by a tapped delay line, a plurality of pulsed sampling signals, wherein each pulsed sampling signal includes a series of frequency harmonics and successive signals of the plurality of pulsed sampling signals are separated by a predetermined delay time;
• mixing each of the plurality of pulsed sampling signals with a time-limited information signal wherein a plurality of mixer output signals is generated;
• bandpass filtering each of the plurality of mixer output signals;
• generating a first plurality of simultaneous TMA beams from the plurality of filtered and weighted output signals by driving a plurality of acoustic transducers in a spatial array of acoustic transducers, wherein each beam of the first plurality of simultaneous beams is associated with one of a plurality of transmitting carrier frequencies,
• wherein a bearing-target doppler ambiguity, a uniform response in bearing, out-of-band spectra leakage interference, peak power level, and cross-beam reverberation are controlled in the first plurality of simultaneous beams, and
• a secondary plurality of beams is formed that includes a plurality of different primary carrier frequencies that intersect the first plurality of simultaneous TMA beams in a far-field, wherein a parametric sonar array is produced;
• receiving multiple echo frequencies of the first and second plurality of TMA simultaneous beams at a spectrum analyzer;
• and,
• processing the multiple echo frequencies of the first and second plurality of TMA simultaneous beams with the spectrum analyzer,
• wherein each spectral component of the multiple echo frequencies corresponds to a unique spatial bearing.