In this paper, the digital algorithm and the device for the demodulation of the quadrature amplitude modulation signals are considered. The fundamental advantages of our approach are simple hardware implementation, minimal number of arithmetic operations required over the signal period as well as the potential interference immunity in the presence of Gaussian noise. The expressions have been found for the error probability and their inaccuracy has been estimated. By means of the statistical simulation methods, the practical interference immunity of the introduced demodulator, together with the influence of phase locking errors have been tested. The introduced demodulator can be implemented either as a device independent from the programmable logic devices, or as an installation unit of the receiver equipment.

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The skin shows the physiological condition of the body’s organs and systems that prevent infections and physical damage. Throughout the ages, in folk medicine, phytotherapy was considered a primary form of treatment in all countries, including Kazakhstan, due to the abundance and availability of plant-based remedies. This paper discusses several medicinal plants that are traditionally used in the treatment of skin diseases in the Republic of Kazakhstan. The chemical composition of these plants was analyzed, with a particular focus on the biologically active basic compounds responsible for their therapeutic efficiency in treating skin ailments.

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A digital meter measuring the signal-to-noise ratio in the channel for transmitting discrete information with a constant amplitude of symbols that are the phase or frequency shift keyed signals is proposed. The desired value of the signal-to-noise ratio is determined based on the number of exceedings of the threshold level by the modulus of the logarithm of the ratio of the amplitudes of the received and previous symbols in the sample of a specified size, while the meter itself is invariant to the absolute levels of the signal and noise. It is shown that in the channel with Gaussian noise, this number depends only on the desired signal-to-noise ratio. The necessary calculation relations are successfully obtained; it is also established that the Gaussian approximation of the symbol amplitude probability density is valid. Statistical simulation of the meter operation has been carried out for receiving binary phase shift keyed signals. It is proven that the given theoretical meter characteristics are in satisfactory agreement with the corresponding experimental data and the small measurement error is provided within a wide range of signal-to-noise ratio values.

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