Patent ID: 8027488

Claim:
A parametric audio generator comprising: (a) an ultrasonic signal source providing an ultrasonic carrier; (b) first and second ultrasonic transducers, said first transducer having a first acoustical-mechanical resonance and said second transducer having a second acoustical-mechanical resonance at a frequency higher than that of said first transducer; (c) a source of audio signals; (d) means for modulating said carrier with the audio signals to form a modulated carrier, whereby the frequency spectrum of the modulated carrier includes both of said transducer resonances; (e) means for driving said transducer with the modulated carrier; (f) means for splitting the modulated carrier into upper and lower frequency-range signals; (g) means for driving said first transducer with said lower frequency range signal; and (h) means for driving said second transducer with said upper frequency range signal.