Sound generation system, ultrasonic wave emitting device, and ultrasonic wave emitting method

An ultrasound emitting apparatus that is mounted on a moving object and emits an ultrasound wave, the ultrasound emitting apparatus comprising:

• an ultrasound signal generating section that generates ultrasound signals;
• an audible signal generating section that generates audible signals;
• an information acquiring section that acquires information on the speed of the moving object;
• a frequency controlling section that adjusts a frequency of the ultrasound signals based on the speed of the moving object;
• and
• a modulation section that generates the ultrasound wave through modulation of the ultrasound signals with the audible signals,
• wherein the frequency controlling section comprises:
• a storage section that stores correspondence of the speed and a frequency deviation that is a finite difference between a Doppler frequency and a reference frequency of the ultrasound signals;
• and
• a calculation section that calculates a target frequency of the ultrasound signals through calculation of the frequency deviation associated with the speed of the moving object in the correspondence and addition of the calculated frequency deviation and the reference frequency.