2022•The collection of scientific works of the National Academy of the National Guard of UkraineOpen access
EVALUATION OF MEASURING SIGNALS ON THE BASIS OF TRIANGULAR TIME PULSE MODULATION FOR CONTROL OF THE TECHNICAL CONDITION OF COMMUNICATION AND DATA TRANSMISSION
Olexandr Iohov, V. Maliuk, Sergiy Tymchenko
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Abstract
A method is proposed for triangular modulation of data on the temporal parameters of the carrier, followed by narrow-band filtering of measuring signals for monitoring the technical condition of communication and transmission facilities, which, compared with the binary modulation method, provides a decrease in the harmonic coefficient of the envelope at approximately the same, fairly small error in setting the amplitude modulation coefficient of the amplitude-modulated signal. The analysis of the obtained relations for the amplitude modulation coefficient of measuring signals with a triangular modulation law showed the following. Unipolar and bipolar carrier pulse sequences lead to the same values of the amplitude modulation coefficient of the generated amplitude-modulated signal, but with a bipolar carrier pulse sequence, the amplitude of the output signal doubles with the same amplitude of carrier pulses (without pulses). With phase modulation, the value of the amplitude modulation coefficient is much less than with width modulation. At the same time, two-way width modulation provides twice the value of the amplitude modulation coefficient than the modulation of the front or cutoff of the carrier pulses. This statement, however, is valid only for small values of the modulation coefficients proportional to the modulation coefficients of the temporal parameters of the carrier pulses with the corresponding numerical coefficients depending on the type of modulation. If the amplitude modulation coefficients are not small, then they are determined by more complex dependencies, but also more accurate, allowing to reduce the methodological error. In this case, for the required values of the amplitude modulation coefficient, the time modulation parameters can be calculated in advance or using the built-in microprocessor and stored in the memory of the measuring device (calibrator).
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