| 摘要 |
PROBLEM TO BE SOLVED: To provide a method small in scale for enabling the reproduction of a sound in a local space and the reproduction of a sound in a wide band which are not compatible by an existing technique. SOLUTION: In this local space loudly speaking method, an inputted signal is divided into the arbitrary number of frequency bands, a signal in one of the bands is reproduced by a primary sound source, a signal having the same band as that reproduced by the primary sound source is used as an input signal, the delay and frequency characteristic of a secondary sound source are controlled on the basis of an output signal from a sensor arranged on the boundary of an arbitrary local space. Thus, a sound emitted to the outside of the boundary is muffled, frequency modulation is applied to a sine wave of an ultrasonic band by other frequency bands obtained by performing frequency band division, and an ultrasonic resonation element is excited by the ultrasonic signal subjected to frequency modulation to generate a signal of the other frequency band as a sound. COPYRIGHT: (C)2005,JPO&NCIPI |
