O.B. Popov1, T.V. Chernysheva2, V.A. Abramov3, K.A. Korostelyov4, K.V. Orlov5

1–5 Moscow Technical University of Communications and Informatics (Moscow, Russia)

1 olegp45@yandex.ru, 2 krba2012@yandex.ru, 3 vabramov44@mail.ru, 4 kirill19990511@yandex.ru, 5 kvororloff@yandex.ru

The main unsolved problem in the digitization of the audio signal is the preservation of the quality of transmission of low-level signals, which make up about 80% of the duration of the musical heritage. According to the adopted regulatory documents, the signal-to-noise ratio when recording an sound broadcasting signal (SBS) should be 56 dB. Thus, with a 16-bit representation, low-level signals, up to 10 bits, are not sufficiently protected, and from 10 to 16 are redundant. In addition, low-level signals are greatly distorted in the process of analog digital conversion, which also reduces the sound quality. The main decision made today is to increase the bit depth of the signal representation. Formats with 24, 32 bits are used, which makes it possible to increase the security of weak signals to 30-50 dB, but significantly increases the signal volume. The second direction is the use of systems with instantaneous com-panding (IC) or near instantaneous companding (NIC), which reduce the volume of the trans-mitted signal, but reduce the assessment of its quality. The authors propose an algorithm for the rational use of dynamic range, which allows maintaining objective quality signal with a decrease in the bit depth of its description. The algorithm is a further development of almost instantaneous companding, the implementation of which became possible with an increase in the speed of audio processor processing and the improvement of signal processing algorithms. The essence of the algorithm is to increase to the maximum signal level before trans-mission over noise transmission of additional information about the coordinates of each segment and the coefficient of amplification. The simulation confirmed the possibility of maintaining the objective quality of transmission while maintaining or even reducing the bit depth of the signal.

Popov O.B., Chernysheva T.V., Abramov V.A., Korostelyov K.A., Orlov K.V. Reduction of distortion of low-level signals during analog-to-digital conversion. Electromagnetic waves and electronic systems. 2024. V. 29. № 2. P. 5−13. DOI: https://doi.org/10.18127/ j15604128-202402-01 (in Russian)

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