[ Technical Papers ]

Journal of the Korean Society of Manufacturing Technology Engineers - Vol. 28, No. 3, pp.176-180

ISSN: 2508-5107 (Online)

Print publication date 15 Jun 2019

Received 08 May 2019 Accepted 31 May 2019

DOI: https://doi.org/10.7735/ksmte.2019.28.3.176

펨토초 레이저 기반 비행시간법 거리측정을 위한 마이크로컨트롤러를 이용한 소형 주파수 측정기 개발

유영진^a ; 이주형^a^{, *}

Compact Frequency Counter Using a Microcontroller for Femtosecond Laser Based Time-of-flight Absolute Distance Measurement

YeongJin Yu^a ; JooHyung Lee^a^{, *}

aDepartment of Mechanical System and Design Engineering, Seoul National University of Science and Technology 232, Gongneung-ro, Nowon-gu, Seoul, 01811, Korea

Correspondence to: ^*Tel.: +82-2-970-6343 Fax: +82-2-974-8270 E-mail address: JLee@seoultech.ac.kr (JooHyung Lee).

Abstract

Time-of-flight (TOF) measurement using a femtosecond laser has nanometer precision over long distance without any ambiguity problem. For commercial use of the high-resolution distance meter, the electronic parts including control, analysis and data acquisition should be compact and rugged as well as lasers and optics. Among the electronic parts, a frequency counter is measuring frequency of the repetition rate of the laser which is directly converted into distance information. In this paper, a compact and cost-effective frequency counter was developed using an 8-bit microcontroller with a Rubidium clock referencing for securing long-term stability. The frequency counter showed measurement error of 0.02 Hz and a measurement stability of 6×10^-4 (at 1 s) and 5×10^-6 (at 100 s) making it potentially applicable to the TOF measurement principle.

Keywords:

Distance measurement, Time-of-flight, Microcontroller, Frequency counter

Acknowledgments

이 연구는 서울과학기술대학교 교내 일반과제 연구비 지원으로 수행되었습니다.

References

Lee, J., Kim, Y. J., Lee, K., Lee, S., Kim, S. W., 2010, Time-of-Flight Measurement with Femtosecond Light Pulses, Nature Photonics 4 716-720. [https://doi.org/10.1038/nphoton.2010.175]
Lee, J., Lee, K., Lee, S., Kim, S. W., Kim, Y. J., 2012, High precision laser ranging by time-of-flight measurement of femtosecond pulses, Meas. Sci. Technol. 23 065203. [https://doi.org/10.1088/0957-0233/23/6/065203]
Dändliker, R., Thalmann, D., Prongué, D., 1988, Two-wavelength Laser Interferometry Using Superheterodyne Detection, Opt. Lett. 13 339-341. [https://doi.org/10.1364/OL.13.000339]
Keysight Technologies, 2008, 10 Hints for Getting the Most from Your Frequency Counter, <https://literature.cdn.keysight.com/litweb/pdf/5989-8431EN.pdf?id=1417079, >.
Lee, S. S., 2015, Micro-controller AVR ATmega128 : System design using state diagram, Hanbit Academy, Seoul.
Microchip, 2011, ATmega128(L) - Complete Datasheet, <https://www.microchip.com/wwwproducts/en/ATmega128, >.
Agilent Technology, 1997, Fundamentals of the Electronic Counters, <http://leapsecond.com/hpan/an200.pdf, >.