D.V. Kondakov1, A.P. Lavrov2, S.V. Zavjalov3

1-3 Peter the Great St. Petersburg Polytechnic University (St. Petersburg, Russia)

1 dmitrii.kondakov@spbstu.ru; 2 lavrov_ap@spbstu.ru; 3 zavyalov_sv@spbstu.ru

Formulation of the problem. Sign al spectrum analysis is a deman ded task in the development of various radio engineering and te lecommunication devices. Commonly used spectrum analyzer devices have a high cost and a limited frequency band in real–time sign al processing (on the order of tens of megahertz), which increases the likelihood of missing signals. Currently, the options for analyzing signals in a wide frequency band are the use of multichannel su b—sampling using digital signal sample processing methods. The paper demonstrates the restoration of the amplitude spectrum of s ignals in a wide frequency band during parallel operation of se veral asynchronous sampling channels with their spectral analysis, th e deployment of frequency responses of channels from the first Nyquist zone to high zones, and subsequent joint processing of the expanded spectra to obtain the spectrum of the input signal. This spectrum is called the reconstructed spectrum of the input sign al. For this purpose, it is assumed that several processing cha nnels with parallel analog-to-digital converters will be used, which differ in the value of the subsampling frequency. An amplitude spectrum is constructed in each channel. At the final stage, the digital processor processes the received amplitude spectra together to construct the final amplitude spectrum of the input signal. Goal. Development of a block for digitizing and restoring the a mplitude spectrum of a broadband signal using multichannel subs ampling methods and construction of an experimental stand for testing the block. Res ult s. A prot otype ofablock for di gi ti zing and res tori ng t he amplitude spectrum of a broadba nd signal using the multichann el asynchronous subsampling method and an experimental setup for t esting the characteristics of the block model were developed. The results were compared with the operation of the BARS-MSA-26S sp ectrum analyzer [1] for single- and multi-signal modes accordin g to the criterion of signal position compliance in the operating frequency range from 0 to 18 GHz with a frequency resolution of 1 MHz. The results demonstrate the corr ect restoration of the spectrum of the original signal. A special feature is the absence of si de responses and the independence of the noise level from the freque ncy in the entire operating range up to 18 GHz. It should be no ted that in comparison with the BARS-MSA-26S spectrum analyzer, the developed block for digitizing and restoring the amplitude spe ctrum of signals using multichannel subsampling methods is cheap er, can provide signal processing in real time in a band of up to 1200 MHz and a limited width of the Nyquist zone of the ADC used (the real-time viewing band for the BARS-MSA-26S spectrum ana lyzer is 20 MHz).

Practical significance. A block for digitizing and restoring th e amplitude spectrum of a signal in a wide frequency band using the multichannel subsampling method and an experimental stand for test ing the operation of the block have been developed and can be used in the development of modern radio engineering systems, since the block is distinguished by the ability to operate in real time in a wide instantaneous operating frequency band with high frequency resolution.

Kondakov D.V., Lavrov A.P., Zavjalov S.V. Experimental test of the method of restoring the amplitude spe ctrum of signals in multichannel subsampling. Radiotekhnika. 2026. V. 90. № 3. P. 181−19 0. DOI: https://doi.org/10.18127/j00338486-202603-16 (In Russian)

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