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• APPLICATION OF HYBRID METHODS FOR NUMERICAL SOLVING OF ORDINARY DIFFERENTIAL EQUATIONS FOR ANALYSIS OF SELF-OSCILLATING CIRCUITS WITH VARIOUS DYNAMICS

  А.М. Pilipenko

  2026-02-27

  Abstract ▼

  Ensuring the accuracy and stability of computer simulation of electronic devices is an important problem in their design. The greatest difficulties in simulation of electronic devices arise in the case of the analysis of self-oscillating circuits, since mathematical models of such circuits can be stiff and oscillating at the same time. The aim of this work is to develop an efficient numerical method for solving ordinary differential equations that provides higher accuracy of time domain analysis for various types of autogenerators compared to existing methods. The proposed method is a hybrid method and is based on the well-known Gear and trapezoidal methods used in simulators of electronic circuits. To evaluate the accuracy of the proposed method and known methods a generalized model of a self-oscillating circuit was used for which an analytical solution was determined in the steady-state operating mode. The accuracy of the numerical solution was determined based on the analysis of errors in estimating the main parameters of the oscillatory process – the amplitude and frequency of oscillations. A comparative analysis of errors in estimating the amplitude and frequency of oscillations in autogenerators demonstrates the high efficiency of the proposed hybrid method for analyzing both harmonic oscillators and relaxation oscillators. A further increase in the accuracy of the hybrid method is possible using implicit Runge-Kutta methods (Rado IIA and Lobatto IIIA subclasses), which have L- and P-stability, respectively. It should be noted that with an increase in the order of accuracy of implicit Runge-Kutta methods, the computational complexity of these methods increases, but for the Rado IIA and Lobatto IIIA subclasses the increase in computational complexity will be minimal.

• 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.

• DIFFERENTIAL-CAPACITORY DEVICE WITH TWO AUTOGENERATORS

  R.N. Nabiyev, G. I. Garaev, R.R. Rustamov

  145-153

  2025-08-01

  Abstract ▼

  The article describes the structure, design, installation, functionality, technical parameters
  of a capacitive device used in security and warning systems for the perimeters of objects, as well
  as a circuit of a patented differential-capacitive sensor with two autogenerators, which is part of
  the device, the probability of detecting unauthorized intrusions is calculated and estimated using
  the device. The operation of the capacitive sensor is found in the transformations of the change in
  the capacitance of two sensitive elements relative to the Earth, the possibility of a protective fence,
  the change in frequency using autogenerators when approaching or touching them on external
  faces, and the principle of operation of the capacitive device is based on detecting detection when
  the frequency difference of the autogenerators exceeds the set limit value. The advantage of
  autogenerators circuits built on logic elements in a differential capacitive sensor is shown, to the
  inputs of which sensitive elements are connected, one of which is used as a signal, and the other as
  a reference generator. It is shown that when RLC-elements with lumped parameters and quartz
  resonators are not used as frequency counters, the circuits of self-oscillators built on digital
  microcircuits according to the same scheme and their adaptation to changes in the external
  environment are greatly simplified. happens automatically. To transfer the high frequency signals
  of the generators to the laptop, first these signals are converted into low frequency signals through frequency dividers, which are in the frequency counters, then these low frequency signals are
  converted into digital signals using the Arduino Uno module. The software written on the laptop
  calculates the frequency difference and generates an alarm at a certain value of the difference.
  According to the calculations, a rather high probability of detecting unauthorized intrusions on
  objects and the efficiency of using a security warning device with a differential capacitive sensor
  based on two self-oscillators in the aviation security system were noted.