| 摘要 |
PROBLEM TO BE SOLVED: To provide an insect pest-repellent apparatus that can effectively repel insect pests as adverse effects to human bodies are alleviated without reduction in indoor workability. SOLUTION: The insect repellent apparatus 10 comprises a clock signal generating circuit 12, a pattern signal generating circuit 14, a timing signal generating circuit 16, a modulation circuit 18, a filter 20, an amplifier 22 and an ultrasonic speaker 24. The clock signal generating circuit 12 outputs a clock signal of a constant frequency within the ultrasonic range to the modulation circuit 18. The pattern signal generating circuit 14 expresses the predetermined characteristics of the voice of a bat and a pattern signal for gradually reducing the frequency of the clock signal is output to the modulation circuit 18. The modulation circuit 18 modulates the clock signal of a constant frequency into FM with the pattern signal. The modified signal is subjected to a prescribed filtration treatment by means of a filter 20, amplified with the amplifier 22 and output through the ultrasonic speaker 24. COPYRIGHT: (C)2004,JPO
|
