The construction of a contactless adaptive vibration sensor based on an externally modulated reflectometer-type fiber-optic transducer is discussed. The sources of measurement error and ways of reducing them are determined. An experimental prototype fiber-optic contactless adaptive vibration sensor and a method for correcting its transfer function are described.
A radiation-resistant diamond-based detector for registration of fluxes of particles of cosmic radiation with low linear energy transfer is developed and investigated. The device may be used to register gamma radiation of water-moderated, water-cooled nuclear energy reactors. The characteristics of a detector when exposed to beta radiation are determined and modeling of the signals of the device when exposed to beta and gamma radiation is performed. The use of a multi-layer diamond structure makes it possible to increase the signal-to-noise ratio and expand the dynamic range of measurements of the linear energy transfer of cosmic radiation particles.
We developed a new method for measuring the pitch frequency of speech signals with elevated noise immunity. The problem of protection against intense background noise is solved in this method by the frequency selection of vocalized segments of speech signals according to a scheme with comb filter of interperiodic accumulation. The efficiency of the method is analyzed both theoretically and experimentally with the help of a multichannel frequency meter intended for the acoustic speech analysis. It is shown that, for a signal-to-noise ratio of 10 dB and higher, the error of the method does not exceed 2%.
The article continues our previous work [V. V. Savchenko and A. V. Savchenko, Izmeritel’naya Tekhnika, No. 12, 46–52 (2019)]. We study the problem of automatic control of the quality of voice samples recorded and stored in the Unified Biometric System. We propose a solution of the problem of timely updates of the collected samples required because their consumer qualities are lost in the course of time. A new indicator of the acoustic quality of voice samples in the Kullback–Leibler information metric is investigated and a new procedure is proposed for measuring this indicator at the times of contact of the users with the system with service requests. An example of practical implementation of the proposed method in the real-time mode is demonstrated. By using software specially developed by the authors, we performed a full-scale experiment and obtained quantitative estimates of the period of updating of voice samples. Some recommendations concerning their practical application are given. The accumulated results can be used for the purposes of development of new systems and technologies (and upgrading of the existing systems) of automatic quality control and adaptive renewal of the biometric personal data samples.
The problem of measuring the temperatures of the radio-electrical components of printed circuits is investigated. A temperature measuring sensor (thermocouple) and possible errors are considered. A systematic error compensation method is proposed to ensure the necessary accuracy of measurements made with the temperature sensor. © 2015 Springer Science+Business Media New York
A neural network approach for processing the output data from a spectrometr with diamond detectors on a spacecraft is discussed. A mathematical apparatus for obtaining differentiable data on fluxes of electrons, protons, and heavy charged particles in 21 energy bands is proposed.
We consider the problems of measuring the temperature of objects heated in high-power microwave installations and show the advantages of using pyrometers for these purposes as compared with thermocouple temperature meters. The procedure of finding the characteristics of below-cutoff waveguides with circular cross sections intended for application in combination with pyrometric sensors is described. We also present the plots for the rapid evaluation of the geometric parameters of circular below-cutoff waveguides depending on the required inserted attenuation. An example of application of a circular below-cutoff waveguide in combination with a KM-1 pyrometer is presented.
We propose a method for designing transversely illuminated traveling-wave microwave devices. Devices of this type produce a uniform 3D temperature distribution in a polymer-composite rod. We describe theoretical and experimental results from studies of the 3D temperature distribution in the rod, along with the advantages of microwave curing technology over traditional curing techniques for polymer composites.
A diamond-based single-element ultraviolet potodetector that may be used in spectrophotometric equipment is developed. The characteristics of the spectral sensitivity of the detector as a function of tha appllied voltage are presented. The capabilities gained from the used of similar devices for systems used in the analysis of the composition of multicomponent mixture are considered.
Improvement of the standards base for optophysical measurements
An inductive time-type analog-to-digital converter for linear displacements has been developed in which the displacement-phase conversion step has been eliminated. The displacement is directly converted into a time interval and then into a digital code. The functional circuit of the converter and its mathematical description are presented. © 2015 Springer Science+Business Media New York.
A method for the construction of microwave devices with longitudinal interaction is proposed. Devices of the present type create uniform cross-sectional distribution of temperature of rods made of polymer composite materials. Results from theoretical and experimental investigations of the cross-sectional distribution of the temperature of the material of the rod as well as the parameters of the microwave device are presented.
The results of theoretical and experimental investigations in the area of high performance microwave technologies for the heat treatment of sheet materials are presented. Two-dimensional periodic slow-wave systems are used as the heating elements of the microwave devices. The disagreement between the theoretical and experimental temperature distribution characteristics in the sheet material and the temperature deviation from the nominal value does not exceed 3% and 5%, respectively.
The specific nature of the process of measuring the electrical characteristics of bipolar and metal-oxidesemiconductor (MOS) transistors subjected to the action of neutron, electron, and gamma irradiation is considered. An automated measurement system is developed. Examples illustrating the use of the system for investigations of the radiation hardness of transistors are presented and the parameters of SPICE models for use in circuit design are determined.
A design is proposed for microwave systems which produce a uniform temperature distribution over the transverse cross section of dielectric pipes. A method for calculating the temperature distribution over the thickness of pipes made of composite materials is examined.
The problem of automated quality control of audio recordings containing voice samples of individuals is considered. It is shown that in solving this problem the most acute impediment is the problem of small samples of observations. To overcome the problem, a new, high-speed method of acoustic measurements is proposed, based on the principle of relative stability of the frequency of the fundamental tone of a speech signal within a voice sample of short duration. An example of practical implementation of the developed method according to a scheme with inter-period signal accumulation is considered. Using proprietary software, a full-scale experiment was conducted in which statistical estimates of the effectiveness of the method in noise conditions were obtained. It is shown that when using the proposed method, if the signal-to-noise ratio is lower than 15 dB, an audio recording is rejected with a probability of 0.95 or more as unsuitable for biometric identification of a person. The results obtained are intended for use in the development of new systems and modernization of existing systems and technologies for collection and automated quality control of biometric personal data. The article is intended for a wide circle of specialists in the field of acoustic measurements and digital processing of speech signals, as well as for practitioners who organize the work of authorized organizations in preparing samples of biometric personal data for registration with the unified biometric system (UBS).
We consider the problem of determination of the intelligibility of speech of a speaker according to a fi nite fragment of the speech signal. It is shown that the main diffi culties in the solution of this problem are connected with the necessity of analysis of small samples. To overcome the problem of small samples, we proposed a new high-speed method for measuring the intelligibility of speech signals on the sonic level of its perception. The proposed method is based on the information indicator of speech intelligibility in the Kullback–Leibler metric. We consider an example of practical realization of the new method with the use of a self-regression model of minimum sound units from the speech fl ow of a speaker. The characteristics of effi ciency of the new method are analyzed. It is shown that, under certain conditions, the application of the information indicator enables us to realize the general systems principle of guaranteed result. On the basis of the software developed by the authors, we designed and performed full-scale experiments and established quantitative estimates for the speed of this method. It is shown that, with the help of this method, quite accurate and reliable estimates of the information indicator are obtained for short (2–3 min) segments of speech signals. The accumulated results and the conclusions made on their basis are intended for applications in the development of new systems and improvement of the existing systems of automatic speech processing and recognition intended for the operation in the real-time mode.
An optoelectronic time-type displacement transducer with different methods of correction of frequency errors is considered. It is shown that the use of an automatic frequency control loop represents the most promising method. A functional circuit of the device is developed and the basic functional dependences are presented.
The operation principle, advantages and disadvantages of resonator sensors are considered. A method of correcting the additional errors of such sensors is proposed. An experimental investigation of the method on string resonator sensors of linear displacements is described.