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• DECIMETER RANGE GENERATOR

  A. N. Zikiy, A. S. Kochubey

  2021-07-18

  Abstract ▼

  The receiver's heterodyne and the transmitter's master oscillator are the most important
  components, as they determine their stability and range properties. In recent years, the Meteor
  plant has created a number of new voltage-controlled generator chips with high electrical parameters.
  However, the advertising materials of this company do not contain a number of parameters
  that are important from the point of view of the consumer. Therefore, the purpose of this work
  is to study the main characteristics of the generator, including those not declared by the supplier:
  the width of the signal spectrum, the average steepness of the modulation characteristic, the level
  of harmonics. The object of the study is the GUN382 microchip in a typical switching circuit.
  The results of an experimental study of a VCO operating in the 1200 MHz region are presented.
  The estimation of parasitic products in the spectrum of the output signal is given. Photos of the
  spectrum of the output signal showing a small width of the spectral line are presented. The modulation
  characteristics are measured when the control voltage and supply voltage change, and their
  average steepness is calculated. These data allow us to make reasonable requirements for the
  stability of the control and supply voltages. The results obtained can be used in receiving and
  transmitting equipment for communication, navigation, and electronic warfare. The article expands
  the idea of the line of generators of the Meteor plant, demonstrates their high electrical
  characteristics: operating frequency range 1200 ± 16 MHz; output power of at least 1 dBm; supply
  voltage + 5V; control voltage from 0 to 8 V; the level of the second and third harmonics does
  not exceed minus 22 dB in relation to the useful signal.

• EXPERIMENTAL STUDY OF QUARTZ CALIBRATOR

  А.N. Zikiy

  107-113

  2025-08-01

  Abstract ▼

  The object of research is a calibrator consisting of a quartz oscillator and a diode-based
  harmonic generator with charge accumulation. The aim of the study is to identify technical parameters
  and characteristics of the calibrator that are absent in the literature. An experimental
  study of a quartz calibrator with a frequency grid at 50 MHz has been carried out. The following
  results are presented: – overrun frequency 20 minutes after switching on; – dependence of the
  frequency of the first harmonic on the supply voltage; – spectrum of harmonics in the frequency
  range from 0 to 1500 MHz. A schematic diagram and a brief description of the design are given. A
  photo and experimental technique are presented. The calibrator is recommended for use in receivers
  and spectrum analyzers to test their performance and improve tuning accuracy. The following
  electrical parameters have been achieved: – frequency setting accuracy of the first harmonic
  ± 2.5 kHz; – power of the first harmonic 0 dBm; – non-uniformity of harmonics in the band from
  0 to 1500 MHz no more than 36 dB; – run-out of the frequency of the first harmonic in 20 minutes
  34 Hz; – frequency drift of the first harmonic when the supply voltage changes from 5 to 13.5 V,
  no more than 288 Hz; – the width of the spectral line at the level of minus 40 dB from the maximum
  is not more than 4 Hz. Comparison of the obtained results with the known ones shows a rather
  large unevenness of the harmonic power in the frequency range up to 1500 MHz. Reducing
  the uneven power of harmonics can be achieved in several ways: – supplement the calibrator with
  a corrector of the amplitude-frequency characteristic; – increase the frequency of the first harmonic. The advantages of this calibrator are the simplicity of the circuit and design, the possibility
  of repetition in the conditions of serial production, the availability of the element base, ease of
  adjustment, small weight and dimensions. Using more powerful transistors, it is possible to cover
  not only the decimeter, but also the centimeter wavelength range