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• ALGORITHM FOR TEMPERATURE CORRECTION OF VIBRATION DENSITY METERS

  O.V. Zatserklyanyi

  2021-02-13

  Abstract ▼

  In this article additional temperature error of vibration density meters in liquids and gases
  is reviewed. Particularly scrutinized are the effects of change in the temperature of the medium
  on the vibration frequency of the density vibration transducers. Main principle of operation
  and advantages of vibration density meters is described. The article analyzes and describes the
  existing algorithms of calculating density and active temperature compensation as well as the
  disadvantages of those algorithms. It points out to the significant limitations of temperature
  calibration diapason of the existing methods which relate to the necessity of using distilled water.
  Basing on the previous vibration transducer simulation and on the established main function of the elastic modules of the metal’ temperature properties a new thermal compensation
  algorithm, which does not involve liquid compensators, was introduced. Main advantages of the
  new algorithm are demonstrated. Those advantages emerge due to using vacuum as a medium
  surrounding the vibration transducer. One of the most notable benefits is significant extension
  of the calibrated temperature range. A possibility of applying the algorithm for calibrating density
  meters in extreme temperatures is introduced. Furthermore, formulas for calculatingthe
  value of the oscillation period of the converter which account for temperature changes (thermal
  compensation period) are presented. The advantages of using second order polynomial with
  zero linear term as a calibration function are also provided. Methodology behind conducting
  the experiments, types of equipment and measuring instruments are described in detail. Resul ting
  experimental data for vibration transducers made of three different metals is presented. The
  obtained data is analyzed, which led to a conclusion that application of suggested algorithm of
  thermal compensation of liquid and gases density meters’ vibration transducers is feasible and
  expedient.

• REDUCTION APPROACH OF TRANSIENT PROCESS OVERSHOOT IN CONTROLLED TUNABLE LOW PASS DIGITAL FILTER

  Al-Karawi Hussein Shakor Mogheer, I.I. Turulin

  2022-08-09

  Abstract ▼

  Digital signal processing is widely used in modern technology, including robotics, medical
  technology, etc. Thus, the controlled digital filters are used to eliminate the constant component of
  the output signal at the output of an analog-to-digital converter. This also reduces the low-frequency
  interference level spread out on the frequency axis to the left of the lower boundary of the signal
  spectrum. In actual situations, signals are subjected to a variety of disruptions and noises; however,
  applying a filter may suppress these noises and produce a clean signal. Controllability means the
  explicit dependence of the filter coefficients on the cutoff frequency. A transient occurrence can arise
  in a digital filter, which is indicated in the overshoot of the signal. A change in the cutoff frequency
  during filtering operation could cause this transient event. In this report, a Butterworth LPF filter is
  used to offer a compensation strategy for reducing this overshoot. A transient is an overshoot (drive)
  in the result timing chart. This drive is an after effect of the adjustment of the coefficients (boundaries)
  of the filter during filtering (this is classified "on-the-fly tuning"). By using the MATLAB program,
  the transient process resulting from the restructuring of the filter was investigated and the
  formulas were checked compensation of this transient process. It was found that the application of
  such compensation reduced the negative effects of the transition process. This decrease depends on
  the order of the filter, the adjustment coefficient (the ratio of cut frequencies before and after adjustment)
  and the moment of adjustment (for the periodic signal).