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• ANALYSIS OF STABILITY AND FEATURES OF PRACTICAL IMPLEMENTATION OF HOGENAUER FILTERS AS RECURSIVE DIGITAL FILTERS WITH FINITE IMPULSE RESPONSE

  I.Е. Moiseenko , S. P. Tarasov , I.I. Turulin

  37-46

  2025-10-01

  Abstract ▼

  The article considers the issues of stability of cascade integrator-comb (CIC) filters used in digital signal processing, including decimation and interpolation. A brief review of modern publications on the architectural optimization of CIC filters is given. The main attention is paid to increasing the stability of filters to the overflow of the bit grid, analyzing their stability and the method of synthesis of recursive FIR filters (filters with a finite impulse response). For a better understanding of the nature of the stability of CIC filters, the paper presents mathematical calculations illustrating the features of the accumulation of the constant component for various block configurations. A change in the structure of the CIC filter is proposed, consisting in the permutation of the integrator and comb filter blocks. It is proved that such a change prevents the accumulation of the constant component of the signal in the integrators and, therefore, eliminates the overflow of the bit grid due to the accumulation of the constant component in the integrator. This approach is based on the property of linear filters, according to which changing the order of inclusion does not affect the transfer function. amplitude-frequency characteristic, but in the case of digital implementations it allows to significantly reduce the probability of overflow. The possibilities of hardware and software implementation of such structures are considered from the point of view of minimizing the loss of accuracy and increasing the reliability of digital signal processing systems. It is proposed to use integers or numbers with a fixed point to eliminate the accumulation of quantization errors. In addition, a program in Python was developed that implements a CIC filter taking into account the stability of the constant component in the input signal and the accurate execution of operations. The obtained results are compared with modern approaches presented in scientific research in recent years. The proposed solutions can be useful in developing digital filters for systems with limited computing resources and increased stability requirements.

• EXPERIMENTAL STUDY OF THE HETERODYNE MODULE

  A.N. Zikiy, A.S. Kochubey

  2021-02-13

  Abstract ▼

  Heterodynes are an integral part of any superheterodyne receiver. They determine the stability
  and accuracy of the receiver settings. The purpose of this work is to create a heterodyne
  module with improved electrical parameters, with small dimensions and weight. The object of
  research is a five-channel heterodyne of the centimeter wave range. Such a heterodyne can be
  used in a multi-channel superheterodyne signal detection receiver. An experimental study of two
  five-channel channels-the upper and lower frequency heterodyne tuning. The results are presented
  in the form of frequency run-out curves for half an hour of operation after switching on, as well as
  the spectra of output signals in the near and far zones. The functional diagram of the module, a
  brief description of the design and the experimental method are given. The design of the module
  has the overall dimensions of the case 170x20x40 mm, is standardized and allows you to integrate
  the module into various receivers. Each channel of the heterodyne module includes a voltage stabilizer,
  an autogenerator with a dielectric resonator, a power amplifier and a power control detector,
  and a power divider by two. As a result of the experiments, the following parameters were
  achieved: – operating frequencies of 9.25 and 16.25 GHz; – maximum output power in the absence
  of an amplifier of at least 2 mW; – the run-out frequency of 80 kHz to 9,25 GHz frequency;
  – run-on frequency 600 kHz for the frequency of 16.25 GHz; – supply voltage + 15 V; – spectral
  line width no more than 5 kHz; –second harmonic suppression of at least 25 dB; – there is an
  on / off switch for each channel of the heterodyne module and built-in health monitoring.