Ultrasound generator, pest extermination system using ultrasound generator and method of controlling ultrasound generator

A pest repellent system comprising:

• a first ultrasonic vibrator configured to generate a first ultrasonic signal having a first frequency during a unit time period;
• a second ultrasonic vibrator configured to generate a second ultrasonic signal having a second frequency during the unit time period;
• a controller configured to control output timings of the first ultrasonic signal and the second ultrasonic signal output from the first ultrasonic vibrator and the second ultrasonic vibrator;
• and
• a speaker, coupled to a vehicle, to transmit a sound signal having a preset audible frequency while the first ultrasonic vibrator and the second ultrasonic vibrator output the first ultrasonic signal and the second ultrasonic signal under control of the controller,
• wherein the first frequency and the second frequency are set so that the first ultrasonic signal and the second ultrasonic signal repel different types of pests, and
• wherein the controller is configured to control the output timings of the first ultrasonic signal and the second ultrasonic signal to exterminate or repel pests based on location information associated with the vehicle.

A method comprising:

• generating modulated signals by modulating driving signals having different frequencies;
• adjusting output timings of the modulated signals to include an output time period of each of the driving signals at least once during a unit time period;
• and
• generating, based on the modulated signals and based on the output timings, a first ultrasonic signal having a first frequency and a second ultrasonic signal having a second frequency;
• and
• controlling, based on location information associated with an ultrasonic vibrator, the output timings,
• wherein the first frequency and the second frequency are set so that the first ultrasonic signal and the second ultrasonic signal repel different types of pests.