+7 (495) 957-77-43
Contacts

Article 7_4_2020

WIDEBAND HF SIGNALS DISPERSION DISTORTION COMPENSATOR BASED ON DIGITAL FILTER BANKS. THEORY AND APPROBATION

Denis S. Chirov, Moscow Technical University of Communications and Informatics, Moscow, Russia, den-chirov@yandex.ru
Elizaveta O. Lobova, Moscow Technical University of Communications and Informatics, Moscow, Russia, lizabeth2@mail.ru

Abstract
The article proposes a computationally effective scheme of the dispersion distortions compensation device, based on the modification of the classical 2M-channel digital filter banks. The main idea of dispersion compensation is equalization of the delay and elimination of the phase shift, because the frequency dispersion of the signal is the delay of the signal at each frequency and the phase shift. The dispersion distortions compensation device involves the set of FIR filters and the delay line. The set of FIR filters eliminate fractional delay are implemented in the compensation scheme by means of the signal re-digitization with the help of the 19-th degree interpolation polynomial. Each of the FIR filters is multiplied by a coefficient that eliminates the certain phase shift. The delay line eliminates the integer part of the delay. Also, this article estimates the required number of channels in a dispersion compensation device based on a bank of digital filters and compares compensation algorithms on the basis of a filter bank and a filter-compensator. Analytical expressions are obtained for the approximate calculation of the maximum and standard deviations of the phase response of the system, reflecting the dependence of the phase response on the number of frequency subchannels, the order of the interpolation polynomial of the interpolator, the length of the polyphase components of the prototype filter, the slope of the dispersion characteristic, and the passband of the filter bank. Besides, a theoretical and experimental study is concluded, the purpose of which is to confirm the performance and efficiency (availability in terms of the signal-to-noise ratio) of the algorithms for compensating for dispersion distortion of broadband signals in the decameter band, embedded in a digital analysis-synthesis filter bank.

Keywords: HF communication, wideband signals, dispersion distortion, digital filter banks, ionosphere.

References

  1. MIL-STD-188-110C. Departament of Defence interface standart. Interoperability and performance standards for data modems. US Department of Defense. 3 January 2012.
  2. M.B. Jorgenson, R.W. Johnson, R.W. Nelson (2013). An Extension of Wideband HF Capabilities. IEEE Military Communications Conference, pp. 1202-1206.
  3. MIL-STD-188-110D. Departament of Defence interface standart. Interoperability and performance standards for data modems. US Department of Defense. 29 December 2017.
  4. D.V. Ivanov. (2006). Methods and mathematical models for study of the propagation of decameter complex signals and correction its dispersion distortions. MarSTU, Yoshkar-Ola.
  5. E.M. Lobov, I.S. Kosilov. (2011). Calculation of noise immunity of broadband ionospheric radio links using noise-like signals based on prediction data. T-Comm. Vol. 5. No. 11, pp. 68-70.
  6. E.M. Lobov, E.O. Smerdova. (2017). Investigation of the quality of algorithms for estimating the slope of the ionospheric channel dispersion characteristics. Telecommunications. No. 6, pp. 28-31.
  7. E.M. Lobov, E.O. Smerdova, N.A. Kandaurov, I.S. Kosilov, B.A. Elsukov. (2017). Optimum estimation and filtering of the ionospheric channel dispersion characteristics slope algorithms. 2017 Systems of signal synchronization, generating and processing in telecommunications (SINKHROINFO), DOI: 10.1109/SINKHROINFO.2017.7997537
  8. E.M. Lobov, Lobova E.O., Kandaurov N.A. (2018). Optimum tracking dispersion distortion compensator. Telecommunications. No. 5, pp. 85-89.
  9. S.S. Adjemov, E.M. Lobov, N.A. Kandaurov, E.O. Lobova. (2019). Methods and algorithms of broadband HF signals dispersion distortion compensation. 2019 Systems of Signal Synchronization, Generating and Processing in Telecommunications, SYNCHROINFO 2019, Yaroslavl, 1-3 July 2019, 9 p. DOI: 10.1109/SYNCHROINFO.2019.8814074
  10. E.O. Lobova, N.A. Kandaurov. (2019). Experimental Results of Dispersion Distortion Compensation of Wideband Signals with a Device Based on a Digital Filter Bank. 2019 Systems of Signals Generating and Processing in the Field of on Board Communications, SOSG 2019, Moscow, 20-21 March 2019, 8 p. (DOI: 10.1109/SOSG.2019.8706758)
  11. V.V. Vityazev. (2017). Multi-speed signal processing. Moscow: Hot line – Telecom. 336 p.
  12. H.S. Malvar. (1992). Signal Processing with Lapped Transforms, Artech House, Norwood, MA. 336 p.
  13. E.O. Lobova, E.M. Lobov, B.A. Elsukov. (2018). Broadband Signals Dispersion Distortions Compensator Based on the Digital Filters Bank. Reports of the 20th International Conference “Digital Signal Processing and its Application – DSPA-2018”, Moscow, Russia, Vol. 2, pp. 487-491.
  14. E.O. Lobova, E.M. Lobov, B.A. Elsukov (2018). Wideband signals dispersion distortion compensator based on digital filter banks. 2018 Systems of signals generating and processing in the field of on board communications, Moscow, 14-15 March 2018, 4 p. DOI: 10.1109/SOSG.2018.8350615
  15. E.M. Lobov, E.O. Lobova, A.A. Kurochkin (2018). Computationally simplified realization of the compensator of dispersion distortions on the basis of the filter bank. 2018 Systems of Signal Synchronization, Generating and Processing in Telecommunications (SYNCHROINFO), Minsk, 4-5 July, 2018, 4 p. DOI: 10.1109/SYNCHROINFO.2018.8457058
  16. T. Karp, N.J. Fliege. Modified DFT Filter Banks with Perfect Reconstruction. IEEE Transactions on Circuits and Systems – II: Analog and Digital Signal Processing, vol. 46, 11, pp. 1404-1414, DOI: 10.1109/82.803480
  17. V.S. Priputin, V.R. Magsumov, E.O. Lobova. (2019). Analysis of Digital Filter Prototype Design Methods for High-Speed Signal Processing Based on Polyphase Filter Bank. 2019 Systems of Signals Generating and Processing in the Field of on Board Communications, SOSG 2019, Moscow, 20-21 March 2019, 4 p. DOI: 10.1109/SOSG.2019.8706751

Information about authors:

Denis S. Chirov, Doct. Tech. Sciences, docent, chief researcher at SRD MTUCI, Moscow, Russia
Elizaveta O. Lobova, postgraduate student MTUCI, minor researcher at SRD MTUCI, Moscow, Russia