| 摘要 |
The present invention provides an ultra directional speaker which modulates a sound of an audible frequency band into a sound of an ultrasonic band and employs a new technology different from a modulation technology obstructing popularization of an ultra directional speaker through a shift to a specific section by using a principle that generates a sound of an actual audible frequency in the air, instead of frequency modulation. A personal position directed speaker system comprises: an ultrasonic modulator for performing Fourier transform on a carrier wave in which an audio signal is frequency-modulated, and shifting the Fourier-transformed carrier wave to a first ultrasonic band of an ultrasonic band higher than an audible frequency band; a symmetrical frequency generation unit for generating bilaterally symmetrical frequencies with reference to a left end frequency of the ultrasonic modulated signal shifted to the first ultrasonic band by the ultrasonic modulator and inserting the bilaterally symmetrical frequencies; an ultrasonic wave generation unit for generating an ultrasonic pulse having a higher output intensity, based on the ultrasonic modulated signal shifted into the first ultrasonic band by the ultrasonic modulator; and an ultrasonic wave generator for combining the ultrasonic modulated signal modulated by the ultrasonic modulator and the ultrasonic pulse generated between the symmetrical frequencies by the ultrasonic generation unit and performing oscillation by performing inverse Fourier transform on a value modulated with the symmetrical frequencies. |
