Результаты поиска по 'digital signal':
Найдено статей: 3
  1. Aksyonov K.V., Alekseev V.P.
    Digital signals filtering in continuous entry data mode operation
    Computer Research and Modeling, 2012, v. 4, no. 1, pp. 55-61

    The article is dedicated to choose of method for digital signal filtering with continuous 'on-line' data entry and to use of filtration algorithm based on the fast wavelet transform for special problem.

    Keywords: digital signal, filtering, wavelet transform.
    Views (last year): 6. Citations: 7 (RSCI).
  2. Deev A.A., Kalshchikov A.A.
    Coherent constant delay transceiver for a synchronous fiber optic network
    Computer Research and Modeling, 2023, v. 15, no. 1, pp. 141-155

    This paper proposes the implementation of a coherent transceiver with a constant delay and the ability to select any clock frequency grid used for clocking peripheral DACs and ADCs, tasks of device synchronization and data transmission. The choice of the required clock frequency grid directly affects the data transfer rate in the network, however, it allows one to flexibly configure the network for the tasks of transmitting clock signals and subnanosecond generation of sync signals on all devices in the network. A method for increasing the synchronization accuracy to tenths of nanoseconds by using digital phase detectors and a Phase Locked Loop (PLL) system on the slave device is proposed. The use of high-speed fiber-optic communication lines (FOCL) for synchronization tasks allows simultaneously exchanging control commands and signaling data. To simplify and reduce the cost of devices of a synchronous network of transceivers, it is proposed to use a clock signal restored from a data transmission line to filter phase noise and form a frequency grid in the PLL system for heterodyne signals and clock peripheral devices, including DAC and ADC. The results of multiple synchronization tests in the proposed synchronous network are presented.

    Keywords: FPGA, FOCL, PLL, subnanosecond time synchronization, single time scale, two-way synchronization method, clock recovery, diversity in-phase clock network, generation of ADC and DAC clock signals.
  3. Alpatov A.V., Peters E.A., Pasechnyuk D.A., Raigorodsky A.M.
    Stochastic optimization in digital pre-distortion of the signal
    Computer Research and Modeling, 2022, v. 14, no. 2, pp. 399-416

    In this paper, we test the performance of some modern stochastic optimization methods and practices with respect to the digital pre-distortion problem, which is a valuable part of processing signal on base stations providing wireless communication. In the first part of our study, we focus on the search for the best performing method and its proper modifications. In the second part, we propose the new, quasi-online, testing framework that allows us to fit our modeling results with the behavior of real-life DPD prototype, retest some selected of practices considered in the previous section and approve the advantages of the method appearing to be the best under real-life conditions. For the used model, the maximum achieved improvement in depth is 7% in the standard regime and 5% in the online regime (metric itself is of logarithmic scale). We also achieve a halving of the working time preserving 3% and 6% improvement in depth for the standard and online regime, respectively. All comparisons are made to the Adam method, which was highlighted as the best stochastic method for DPD problem in [Pasechnyuk et al., 2021], and to the Adamax method, which is the best in the proposed online regime.

    Keywords: digital pre-distortion, signal processing, stochastic optimization, online learning.

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