| 摘要 |
A system for the production of localized audible sound, including a source of voltage oscillations in the ultrasonic frequency range, at a reference frequency. The voltage source is connected to a first ultrasonic transducer, emitting a first beam of ultrasonic waves (the reference beam) in a relatively narrow beam, in a desired direction. The same voltage source is connected to a phase shifter, feeding a second ultrasonic transducer from which an ultrasonic wave is emitted, of the same frequency and intensity as the reference beam, but phase shifted relative to it. |
