Том 62, № 1 (2019)

The possibility of expanding working frequency ranges and increasing the precision of State Primary Special Standard of the unit of frequency deviation GET 166–2004 is considered. Methods and means of measuring the frequency deviation that may be incorporated into the improved GET 166–2004 are proposed. Results of studies of the following four independent methods of measuring frequency deviation are presented: method of electronic computer frequency meter; method of direct digital synthesis; method of Bessel function zeros; and method of measuring the extremal values of the period.

Structurally parametric identification of the characteristics of the dispersion in the Friedmann–Robertson–Walker model and its approximations as models for cosmological distance scales are examined on the basis of the data on type SN Ia supernovae used to detect the “acceleration in the expansion of the universe.” It is shown that the deviations from the position characteristics of these models as a function of distance (the scale factor) are multiplicative. Estimates of the convolutions of the random and nonparametric unexcluded systematic components of the inadequacy errors of the Friedmann–Robertson–Walker model are obtained in the class of truncated distributions with zero curvature parameter and a Heckmann approximation with anisotropy and interpolation models taken into account.

A discretization method for the range of values of a multidimensional random variable is considered. Its dependence on the volume, dimension of the initial information and the type of probability density is investigated. The obtained results are compared with the Scott rule for a multidimensional random variable with a normal distribution law.

A complex-functional unit has been developed for measuring the speed of writing (reading) SD cards based on the “system on chip” technology. It is shown that using this block it is possible to exchange data between a computer and memory cards both sequentially and in parallel. We present a method for determining the speed of information transfer between external drives and the processor core of systems on a chip. We obtain results for measuring the speed of writing (reading) of various memory cards. Confidence intervals of measurements are determined.

An original design is proposed that makes it possible to create a two-channel optoelectronic instrument for diagnostics of the shape and quality of intraocular lenses. This instrument consists of a collimation-type channel and a channel based on a Shack–Hartmann wavefront sensor. The hardware characteristics of the instrument are examined, i.e., the radius of curvature of the wavefront in the plane of the lens raster, and the dynamic range to which possible measurable aberrations of the intraocular lenses are restricted. A methodology is proposed for diagnostics of the design parameters of intraocular lenses. The systematic error of the output parameter of the instrument being developed is examined within the framework of precision calculations. The calculations that were performed made it possible to transfer to the design stages of an optoelectronic instrument based on the wavefront sensor for monitoring the parameters of the shape of intraocular lenses.

The effect of the rotation of the lens axis to the video camera sensor axis in an optical system equipped with a Scheimpflug adapter has been studied. For optical systems in which the plane of the receiver sensor is not perpendicular to the optical axis of the lens, a methodology has been proposed for determining the depth of field from an image of the background screen. A unit containing a Scheimpflug adapter for photographing the background screen is described. Distributions are obtained for the standard deviation of each column of the matrix of the image of the background screen relative to the zero column, for various relative positions of the axes of the video camera sensor and the lens.

Aspects of the use of a laser meter that measures pressure variations in a hydrosphere functioning as a laser-interference bottom seismograph capable of recording variations in displacements of the floor are described. The capabilities of the bottom seismograph are demonstrated in recording of seismic signals.

The influence of harmonic interference on the metrological characteristics of the output signal of a passive hydrogen frequency standard is analyzed. It is shown that the additional signals in the control circuit generated by the interference lead to the appearance of a frequency shift or parasitic modulation of the frequency of the standard. Results of an experimental investigation of interference suppression of passive hydrogen frequency standards are presented and methods of increasing interference suppression are also considered. The results obtained confirm a theoretical analysis.

The method of comparison for the transmission of the units of volume gas flow from standard critical nozzles to calibratable nozzles is described. A flow laminarizer with flat slitted channels 0.8 mm in height exhibiting a direct proportional relation between the pressure drop in the channel and the volume flow is used as a comparator (modulus of comparison). The flow laminarizer is characterized by high sensitivity to variations in the flow, a broad range of the flows that may be employed, simplicity of the device, and the absence of moving units. Through the use of the present method of comparison in State Primary Standard of the unit of volume flow and mass flow of gas GET 118–2017, it was possible to reduce the load on the expensive bell-type primary bell-type standard plant, decrease the number of standard nozzles required, significantly increase the productivity, and decrease the cost of calibration operations.

Experimental thermograms obtained on samples of different shapes and sizes under spontaneous cooling, pulsed resistive heating, or laser surface heating of the solid phase of high-temperature metals are analyzed. It is shown that all the thermograms can be ascribed to a linear thermodynamic regime. A linear dependence of the entropy production density on the rate of variation of the temperature is found on analyzing the thermograms. This means that the rate of variation in the temperature can be regarded as an additional variable for the entropy production density in the linear regime and can be used for representing properties measured in a nonstationary thermal regime.

We demonstrate that it is possible to compensate for electric-field-strength sensor electrode noise due to variations in fluid velocity relative to the sensor electrodes. This compensation will provide more than a factor of two increase in the sensitivity of the electric-field-strength measurement device. We propose a device design for electric field strength measurements in seawater in the extremely-low-frequency and super-low-frequency bands.

It is shown that the modulus of the error vector is one of the main parameters characterizing the quality of modulation in the digital radio communication systems and makes it possible to perform the quantitative description of the errors in the formation and demodulation of digital signals. The possibility of application of a new method proposed for the assessment of the accuracy of determination of the modulus of the error vector is studied. The new method is based on the use of the combination of two sinusoidal signals or signals with amplitude and phase modulations. The advantages and limitations of the application of this method are analyzed.

We describe the procedure of laboratory experiments aimed at the determination of the indices of accuracy of the developed method aimed at the evaluation of the chemical stability of jet-engine fuels and an algorithm of processing of the experimental results. The parameters of repeatability, laboratory precision, and accuracy of the method are evaluated.