O.B. Popov1, T.V. Chernysheva2, K.V. Orlov3, P.S. Sapronov4

1–4 Moscow Technical University of Communications and Informatics (Moscow, Russia)

1 olegp45@yandex.ru, 2 krba2012@yandex.ru, 3 kvororloff@yandex.ru, 4 pavelozone@gmail.com

The main method of spectral analysis of the sound broadcasting signal (SBS) remains the fast Fourier transform. One of its disadvantages is insufficient resolution, which does not allow to estimate closely spaced spectral components of the SBS, as well as a sufficiently rich spectrum of side lobes deter-mined by the window function used. The need to use window functions also leads to the need to work with overlaps of the analyzed sequence. The resolution of the discrete cosine transform (DCT) is twice as high, but its use was constrained by a wide range of side lobes. The advantage of DCT is also the absence of the need to use window functions, and, accordingly, overlaps. The authors propose an algorithm for a complex DCT with side lobe compensation and in-creased accuracy of determining the parameters of the spectral components due to multiple transposition of the SB spectrum. The algorithm allows to bring the resolution and accuracy of spectral analysis closer to the parameters of the human peripheral auditory analyzer. The developed algorithm of complex cosine discrete transform provides formation of an estimate similar to DFT but with twice higher resolution and lower level of side lobes due to use of active window functions.  The obtained results showed the efficiency of the developed algorithm and the prospects of its use in analysis of the spectrum of the audio signal, its coding and processing.

Popov O.B., Chernysheva T.V., Orlov K.V., Sapronov P.S. Spectral analysis of audio signal using complex discrete cosine transform. Electromagnetic waves and electronic systems. 2025. V. 30. № 4. P. 5−13. DOI: https://doi.org/10.18127/j15604128-202504-01 (in Russian)

1. Kovalgin Yu.A. Digital radio broadcasting: systems and technologies. Moscow: Hotline-Telecom. 2021. 580 p. (in Russian)
2. Recommendation ITU-R BS. I 284-2 (01/2019). General methods for the subjective assessment of sound quality. BS Series. Broadcasting service (sound).
3. Abramov V.A., Popov O.B., Chernysheva T.V., Taktakishvili V.G., Ovchinnikov A.A. On-board Transmission Quality Assessment Using Short Audio Signal. Systems of Signals Generating and Processing in the Field of on Board Communications, Conference Proceedings. Moscow. 2021. P. 9416085. DOI 10.1109/IEEECONF51389.2021.9416085.
4. Patent for the invention RUS2756934 dated 07.10.2021. Method and device for measuring the spectrum of information acoustic signals with distortion compensation. Abramov V.A., Popov O.B., Vlasyuk I.V., Balobanov A.V. (in Russian)
5. Certificate of state registration of the computer program № 2022616423 dated 19.04.2022. Program for high-precision spectral analysis of an audio signal ACCORDING to "DKP-Spectrum" Version 2022. Popov O.B., Kuznetsov P.G., Abramov V.A., Makarina D.A., Ovchinnikov A.A. (in Russian)
6. Bai T., Xie L., Li Z., Yang J., Chen Z., Wan P. A High-Precision Audio Z-Δ D/A Converter. IEEE 14th International Conference on Anti-counterfeiting, Security, and Identification (ASID). Xiamen, China. 2020. P. 120–123. DOI 10.1109/ASID50160.2020.9271769.
7. Klimov S.A., Semchenkov S.M., Ashikhmin A.V., Kovalenkov A.N., Rachkovsky S.S. Features of modeling radar measurements in an echole acoustic camera. Electromagnetic waves and electronic systems. 2020. V. 251. № 5. P. 7−18. DOI 10.18127/j15604128-202005-02. (in Russian)
8. Aladinsky V.A., Kuzminsky S.V., Chubatyi D.N. The choice of recognition features for low-speed speech encoding protocols. Electromagnetic waves and electronic systems. 2019. V. 24. № 8. P. 72–76. DOI 10.18127/j15604128-201908-11. (in Russian)
9. Patent for invention RUS2813684 dated 15.02.2024. Method and device for measuring the spectrum and cepstral parameters of information acoustic broadcasting signals. Abramov V.A., Popov O.B., Chernysheva T.V., Borisov A.A. (in Russian)
10. Certificate of state registration of the computer program № 2024666254 dated 11.07.2024. The program for the complex discrete cosine transformation "DCTchecker". Popov O.B., Abramov V.A., Volchkov D.A., Orlov K.V., Korotelev K.A. (in Russian)
11. Certificate of state registration of the computer program № 2013617341 dated 09.08.2013. Accurate spectral analysis of the Spectran audio signal. Abramov V.A., Popov O.B., Chernikov K.V. (in Russian)
12. Recommendation ITU-R BS.1387-2 (05/2023) Method for objective measurements of perceived audio quality.