The Journal of Korean Institute of Communications and Information Sciences (한국통신학회논문지)

The Korean Institute of Commucations and Information Sciences (한국통신학회)
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The GMSK Modulation for Bipolar Delta Signal

바이폴라 델타 신호에 대한 GMSK 변조

  • 방승철 (동서울대학교 정보통신과) ;
  • 이우상 (동서울대학교 정보통신과)
  • Received : 2013.05.26
  • Accepted : 2013.07.04
  • Published : 2013.07.31
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Abstract

In the basic GMSK, the modulated signals are generated by the preprocessing of NRZ pulse trains with the gaussian low pass filter. In this paper, we proposed the GMSK modulation system with the delta pulse trains. The proposed system constructed with the gaussian pulse generator triggered by the bipolar delta pulse, the differentiator between $+T_b/2$ and $-T_b/2$, and then a matched filter for frequency-modulation function. The spectrum of proposed system was found to be smaller than about 35[%] at 40[dB] attenuated bandwidth, and the center spectrum to be lower than the basic GMSK with zero-crossing property.

기본적으로 GMSK는 NRZ 펄스열을 가우시안 저역 통과 필터로 전 처리한 후에 GMSK 신호를 생성하지만, 본 논문에서는 델타 펄스열에 대한 GMSK 변조 시스템을 제안하였다. 제시된 시스템은 바이폴라 델타 펄스로 가우시안 펄스를 발생시키는 가우시안 펄스 생성기, $+T_b/2$와 $-T_b/2$ 사이의 차분기, 그리고 주파수변조 함수를 위한 정합 필터로 구성한다. 기본적인 GMSK 변조와의 비교를 통해 스펙트럼은 40[dB] 감쇠 대역폭에서 약 35[%] 협소하며, 스펙트럼의 중심은 더 낮고, 제로 크로싱 성질이 있는 것으로 나타났다.

Keywords

References

  1. E. Grayver. Implementing Software Defined Radio, XVIII, Springer, 2013.
  2. G. L. Lui, "Threshold detection performance of GMSK signal with BT=0.5," in Proc. IEEE Military Commun. Conf. (MILCOM), vol. 2, pp. 515-519, Boston, U.S.A., Oct. 1998.
  3. T. Turletti, "GMSK in a nutshell," Telemedia Networks and Systems Group LCS, MIT-TR, Apr. 1996.
  4. D. Daly, "Direct GMSK generation using sigma-delta modulation," M.S. Thesis, Div. Eng. Sci., Univ. Toronto, Apr. 2003.
  5. R. Hunter and F. Kostedt, "Enhance GMSK performance with two-point modulation," Microwaves & RF, vol. 39, no. 4, pp. 59-69, Apr. 2000.
  6. A. Linz, "Efficient implementation of an I-Q GMSK modulator," IEEE Trans. Circuits Syst. II, Analog Digit. Signal Process., vol. 43, no. 1, pp. 14-23, Jan. 1996. https://doi.org/10.1109/82.481470
  7. Kuchi Kiran, "Power spectral density of GMSK modulation using matrix methods," in Proc. IEEE Military Commun. Conf. (MILCOM), vol. 1, pp. 45-50, Atlantic City, U.S.A., Oct.-Nov. 1999.
  8. R. B. Staszewski and P. T. Balasara, All-digital Frequency Synthesizer in Deep-submicron CMOS, John Wiley & Sons Inc., 2006.
  9. E. W. Ng and M. Geller, "A table of integrals of the error functions," J. Research Nat. Bureau Standards-B Math. Sci., vol. 73B, no.1, pp. 1, Jan. 1969.
  10. L. Hars, "Formulae and algorithms for the GMSK modulation," in Proc. DSP World Workshop, Toronto, Canada, pp. 221-238, Sep. 1998.
  11. R. N. Bracewell, The Fourier Transform and Its Applications, 3rd Ed., McGraw- Hill, 2000.
  12. V. K. Ingle and J. G. Proakis, Digital Signal Processing Using MATLAB, 3rd Ed., Cengage Learning, 2010.
  13. T. Svedek and M. Herceg, and T. Matic, "A simple signal shaper for GMSK/GFSK and MSK modulator based on sigma-delta look-up table," Radio Engineering, vol. 18, no. 2, pp. 230-237, June 2009.
  14. E. Marpanaji, B. Riyanto, A. Z. R. Langi, A. Mahendra, and T. Liung, "Simulation and experimental study of GMSK modulation on SDR platform," in Proc. Int. Joint Conf. TSSA WSSA, pp. 247-252, Bandung, Indonesia, Dec. 2006.
  15. T. C. Weigandt, "Low-phase-noise, low-timing-jitter design techniques for delay cell based VCOs and frequency synthesizers," Ph.D. dissertion, Univ. California, Berkeley, U.S.A., Spring 1998.
  16. M. Kalman, "Zero-crossing based demodulation of minimum shift keying," Turk. J. Elec. Eng., vol. 11, no. 2, pp. 75-94, Jun. 2003.