표제지
목차
국문요약 10
I. 서론 12
II. 이론적 배경 14
2.1. 기존 음성안내 시스템 현황 14
2.2. 기존 음성안내 시스템의 동작원리 16
2.3. 기존 음성안내 시스템의 문제점 20
III. 초음파를 이용한 거리 측정 22
3.1. 초음파의 종류 22
3.1.1. 종파 23
3.1.2. 횡파 24
3.1.3. 표면파 25
3.1.4. 판파 25
3.2. 주기인식 검출방식을 이용한 초음파 거리측정 26
3.2.1. 체공시간의 검출방식 26
3.2.2. 주기인식 검출방식 29
3.2.3. 초음파를 이용한 거리 측정 시스템 30
3.3. 초음파 측정 실험의 목적 31
IV. 실험 및 고찰 32
4.1. 실험방법 32
4.2. 실험결과 36
4.2.1. 수신강도 측정 36
4.3. 고찰 46
V. 결론 48
참고문헌 50
ABSTRACT 52
Table 1. Names of the sound waves by frequency range 22
Table 2. Test specification 32
Table 3. Ultrasonic wave transmitter specification 33
Table 4. Ultrasonic wave receiver specification 34
Table 5. Reception power by distance at 30㎑ ultrasonic wave 37
Table 6. Reception power by distance at 40㎑ ultrasonic wave 39
Table 7. Reception power by distance at 50㎑ ultrasonic wave 41
Table 8. Reception power by distance at 60㎑ ultrasonic wave 43
Table 9. Average power of ultrasonic wave by distance 45
Figure 1. Frame type of the voice information system 17
Figure 2. Example of the stationary device installation and the appearance of the mobile device 18
Figure 3. Structure of the stationary device of the voice information system 18
Figure 4. Operation sequence of the existing voice information system 19
Figure 5. Configuration of the existing voice information system 20
Figure 6. The definition of T.O.F. 27
Figure 7. Threshold method. 28
Figure 8. Envelop method. 28
Figure 9. Variable ultrasonic transmitter 33
Figure 10. Variable ultrasonic receiver 34
Figure 11. Plane view of the ultrasonic wave reception distance test environment 35
Figure 12. Test environment at a 5m ultrasonic wave reception distance 35
Figure 13. Transmitter power value at 53㏈ ultrasonic wave 36
Figure 14. Average power of the ultrasonic wave by distance at 30㎑ transmission wave 38
Figure 15. Comparative analysis of the average power of the received ultrasonic wave by distance at 30㎑ 38
Figure 16. Average power of the ultrasonic wave by distance at 40㎑ transmission wave 40
Figure 17. Comparative analysis of the average power of the received ultrasonic wave by distance at 40㎑ 40
Figure 18. Average power of the ultrasonic wave by distance at 50㎑ transmission frequency 42
Figure 19. Comparative analysis of the average power of the received ultrasonic wave by distance at 50㎑ 42
Figure 20. Average power of the ultrasonic wave by distance at 60㎑ transmission frequency 44
Figure 21. Comparative analysis of the average power of the received ultrasonic wave by distance at 60㎑ 44