Measurements of wattless power and the power factor with a nonsinusoidal current and voltage

Conclusions The above method can be used both for a direct measurement of wattless power and the power factor in single phase commercial and audio-frequency circuits (Fig. 1) and for checking and calibrating (Fig. 2) single phase VAR meters and phasemeters, including those designed for sinusoidal variables.The differential wattmeter is being used successfully in compensation method calibration and checking of three-phase phasemeters with two voltage coils [5 and 6] and phasemeters with two current coils.     

Determining the short-term instability of quartz oscillator frequencies

Summary The measurement results show that phase shift in the instrument depends but very little on the voltages of the frequencies being compared or the sources of supply, thus providing the possibility of using the above instrument for comparing frequencies of crystal oscillators continuously throughout the day and night with great precision.This instrument in conjunction with the phase shifter can also be used as a phase meter for measuring phase shift with great precision. Thus, the error in measuring a phase difference at 60 kc does not exceed 1 · 10^–4 rad.If required it is possible to raise the precision of frequency deviation measurements by either increasing the sensitivity of the discriminators by means of larger input voltages to the discriminator, or by multiplying the frequencies under comparison.     

Measurement of high dc voltages by means of an electron-diffraction camera

Conclusions The above technique and the cited examples for computing the voltage from electron-diffraction patterns of NaCl show that it is already possible to measure by means of an electron-diffraction camera éG-100 A high dc voltages up to 100 kV with an error of 0.1–0.2% For certain specimens whose electron gun can withstand voltages up to 120–150 kV the maximum measurement range is extended accordingly. Therefore, the above method of measuring high dc voltages can be used for checking high-tension instruments, including electrostatic kilovoltmeters. Moreover, the same method can be used for measuring the ratios of high-tension dividers directly with the operating voltages across them, which could not be done so far. In measuring the ratio of dc dividers by comparing them with reference resistors at low voltages it is impossible to evaluate the errors due to the heating of resistors by the operating current, to corona discharges, to leakages and space charges along the surface of the divider.The utilization for these purposes of an absolute method which consists of measuring high voltages by the diffraction of electrons raises the reliability of test results and undoubtedly will be of interest for practical application.     

IAN-3 measuring instrument for the precision measurement of high voltages in X-ray apparatus

The IAN-3 measuring instrument for accurate measurements of anode voltages with ripples in x-ray apparatus in the 40–125 kV range has been developed. The measuring instrument, the method of adjusting and calibrating it, and the results of the calibration are considered. The measurement error does not exceed 0.25%. The IAN-3 measuring instrument can be used to calibrate radiation-type kilovoltmeters and for adjusting medical x-ray diagnostic equipment. Translated from Izmeritel'naya Tekhnika, No. 2, pp. 49–51, February, 1998.     

Low-value UHF film resistors

Conclusion The application of the technique described above for determining coefficienta of the frequency characteristic and the use of appropriate corrections for the effect of the external temperature and for the aging of resistors made it possible to determine the value of |¯Z_H| with an error not exceeding ±(2–3)% at a frequency of 1000 Mc.The UHF film resistors made in the manner described above have values between 0.1·10^–3 and 10·10^–3 ohm. and are suitable for use in instruments measuring small voltages at radio and ultrahigh frequencies.     

关于测点分布的矩阵分析

根据设备故障的诊断需求,对测点的分布特性进行了系统分析,提出了测点信息矩阵的概念,并分析了信息矩阵的性质。以此为基础,研究了测点的优化设置方法,提出了测点分布的优化原则,最后给出了基于测点信息矩阵的测点分布优化算法。     

Equipment for oscilloscope observation of the traveling-wave factor in ultrahigh frequency channels

Summary The above equipment made it possible sharply to decrease the time required for measuring the traveling wave factor, provided a graphic representation of the measurements, and speeded up the adjustment and checking of waveguide channels.Translation from Izmeritel'naya Tekhnika, 1960, No. 11, pp. 47–49, November, 1960     

Method for measuring inductances and capacitances with currents displaced by 90°

Conclusions Circuits with a 90° phase difference between currents can be used for a rapid and sufficiently accurate measurement of inductances and capacitances both with sinusoidal and nonsinusoidal supply voltages.At present these instruments are used by the author at the electrical measuring laboratory of the Jassy polytechnical institute for measuring not only linear inductances but also inductance coils with steel cores and capacitors with losses.     

Variable power phase lenses

A method is given to construct a phase lens capable of creating an optical aberration of variable power that is described by a single Zernike polynomial function whose meridional index is 1 or greater. The phase lens is created from two identical phase elements, each creating a single Zernike aberration, that can be rotated with respect to each other, thereby increasing the aberration effect from zero to twice the value of either. This is possible because these aberrations are vectorlike. Results are given from the testing of an example that was manufactured and designed to produce coma (Zernike term Z(3,1)).     

Microprocessor-Controlled Potentiometric System for Nanovolt Measurements

In order to complete an automatic system for EMF comparison of standard cells in a reference group, an automatic potentiometer at nanovolt level was implemented. However, the equipment can be dedicated for general purpose measurements of dc voltages lower than 1 V. The system reproduces the techniques of manual potentiometers opposing the unknown voltage against a compensation voltage. Starting from the unbalance signal of a galvanometric photocell amplifier, a microcomputer provides a suitable strategy of null balance, acting on the compensation source and the galvanometer sensitivity. In this way, the current in the measuring circuit is continuously kept at an almost zero value. With respect to manual potentiometers, this apparatus does not require an operator and reduces the measurement time. The period of a measurement cycle depends on the present noise level and the number of successive balances. A time of about 2 min is typical for a peak noise of 1 nV.     

Measuring the root-mean-square values of random voltages with tube voltmeters

Conclusions The above examples indicate that in using standard tube voltmeters for measuring root-mean-square values of noise voltages it is necessary to take into account the distribution laws of their instantaneous values. Otherwise substantial errors can be made. By using the above technique it is possible to find the required corrections for every type of voltmeter and any kind of distribution law of a stationary random process.Translated from Izmeritel'naya Tekhnika, No. 10, pp. 49–51, October, 1970.     

Two-channel frequency converter with quartz filters

Conclusion The method described for reproducing phase shifts between two voltages at elevated and high frequencies can be recommended as a beginning in constructing standard phase measuring apparatus.Theoretical investigations have shown that the error in the method can be reduced to 0.04–0.05°.Translated from Izmeritel'naya Tekhnika, No. 3, pp. 60–62, March, 1969.     

Study of an infrasonic generator

Summary As the result of the tests carried out by us it was established that the electromechanical infrasonic generator provides two sinusoidal voltages, displaced in phase by 90°. The phase angle error between these voltages does not exceed ±0.2 the range of the generated frequencies is 0.01–1 cps; the frequency instability does not exceed ±0.2%; the maximum output voltage is 100 v; the amplitude instability does not exceed ±0.3%; the nonlinear distortion factor does not exceed ±0.5 %; and the maximum background noise and interference at the output does not exceed 300 mv in the dynamic operating condition.The generator completely satisfies the requirements of precision measuring generators in the range of infrasonic frequencies.G. A. Martynov and Yu. I. Yanova participated in this development work.     

Measuring the diameter of a moving microwire conductor

Conclusions The dynamic properties of the automatic equipment model make it possible to measure the conductor diameters of the above microwires with an error of 0.5–0.7 for a wire propulsion speed of 2.5 mm/sec.Such systems are suitable for application in special measuring laboratories. If the measuring channels' operating speed of the polar-coordinate autocompensators is improved it will be possible to use them for manufacturing microwires with stable diameters.Translated from Izmeritel'naya Tekhnika, No. 11, pp. 39–41, November, 1974.     

Electron tube Amplifiers

Conclusions Up-to-date electrometer tube amplifiers are a perfect equipment for measuring currents and voltages from sources with a large internal resistance, and they can be used for solving a wide range of problems related to electrometric measurements. The current sensitivity of mass-produced tube electrometers amounts to 10^–15–10^–14 A. Several problems, such as obtaining a logarithmic scale and high-speed systems for measuring very small currents are best solved by means of tube electrometers. It is true that in recent years tube electrometers have acquired an important rival consisting of electrometers with field-effect transducers; however, the latter are as yet in the development stage and one can expect that tube electrometers will for a long time occupy the leading position among other systems used for similar purposes.Translated from Izmeritel'naya Tekhnika, No. 12, pp. 39–44, December, 1966.     

An experimental investigation of the stability of CMOS-logic integrated Schmitt triggers to ultra-short pulse overloads

The degradation of semiconductor CMOS structures due to the action of overloads in the form of ultra-short video pulses is investigated. It is shown that these video pulses in Schmitt triggers produce a change in the threshold voltages and a contraction of the area of uncertainty. In buffer elements, intense phase noise occurs, while in RC generators there is a change in the length and repetition frequency of the pulses generated. Experimental equipment for determining the critical parameters of the actions of ultra-short video pulses on a sample of digital microcircuits and CMOS structures is described.     

Magnetic Potentiometer of High Precision

A magnetic potentiometer is described, the measuring error of which is in the order of 0.1 percent. The measuring winding is on polished straight ceramic rods, the joints of which are kept free from magnetic field by magnetic screening. Thus a measuring frame for heavy currents arises, the mutual inductance of which is independent of the primary circuit situation and of neighboring busbars. The exact measurement of the ac voltages induced can be made with the aid of measuring contacts or also with integrating electronic amplifiers, so that the rms value, fundamental oscillation, and harmonics and phase angle of heavy currents can be measured reliably. The practical error effects in these devices have been examined by the Physikalisch-Technische Bundesanstalt, Berlin.     

Device for measuring energy of radiation pulses from a laser operating in the frequency mode

Conclusion In the device described, a semiconductor diode is used as the radiant energy receiver. Although the photoelectric method is not absolute, practice shows that instruments based on it can be used successfully for measuring the energy of laser radiation pulses when calibrating these devices by means of calorimeters, bolometers, etc. An operating test of the device described for measuring the energy of laser radiation pulses showed its high sensitivity stability.The great advantage of the photoelectric method is the high rate of repetition of the measurements, which is unattainable by the use of calorimetric methods.The use of two channels of different sensitivity for measuring the energy of radiation of one wavelength makes it possible to extend the dynamic range. The number of measurement channels in principle can be even greater than two, which extends the possibility for its use in controlling the energy characteristics of a laser.Translated from Izmeritel'naya Tekhnika, No. 12, pp. 40–43, December, 1974.     

调频信号的数字化解调

介绍一种用3参数正弦波拟合算法实现的、绝对收敛的4参数最小二乘正弦波拟合算法，给出了其收敛区间、绝对收敛判据以及实现过程，在此基础上讨论实现正弦载波的调频信号的精确解调问题，使用一个周期的正弦波曲线模型的滑动拟合法，实现了频率调制信号波形的精确解调，在调制信号是方波的情况下，给出了频率解调的仿真结果和其它参数的波动情况；在1个实测调频曲线波形上进行的解调分析，给出了频率调制波形的解调结果，同时，在调制信号也是正弦波的情况下，给出了解调失真的计算方法和结果。本方法是评价载波为正弦波的调频信号的一种优良方法，准确度高、分辨力强，可用于调频信号源及其解调设备的指标评价和计量测试。