Estimating the total error for a distributed group standard for time and frequency

Studies have been made on the systematic and random errors in the group frequency and time scale for a distributed group standard for the units of time and frequency. A new approach has been devised for calculating the total error of secondary standards. __________ Translated from Izmeritel’naya Tekhnika, No. 6, pp. 24–26, June, 2008.     

Possibility of using low-energy nuclear transitions as benchmarks for frequency stabilization

The fundamental possibility of using low-energy nuclear transitions for obtaining highly stable frequency standards is considered. __________ Translated from Izmeritel’naya Tekhnika, No. 12, pp. 3–4, December, 2007.     

Parameter measurement for the acoustic output of hand-held ultrasonic fetal heartbeat detectors

Methods and instruments are considered for measuring the parameters of the acoustic output from a Doppler ultrasonic detector for fetal heartbeat frequency as corresponding to the specifications of international and national standards. __________ Translated from Izmeritel’naya Tekhnika, No. 11, pp. 55–59, November, 2006.     

Primary Atomic Frequency Standards at NIST

The development of atomic frequency standards at NIST is discussed and three of the key frequency-standard technologies of the current era are described. For each of these technologies, the most recent NIST implementation of the particular type of standard is described in greater detail. The best relative standard uncertainty achieved to date for a NIST frequency standard is 1.5×10⁻¹⁵. The uncertainties of the most recent NIST standards are displayed relative to the uncertainties of atomic frequency standards of several other countries.     

Modified Calibration Coefficients of Two-Port CPW Standards with Superstrate Effects

Calibration standards are used for the calibration of a vector network analyzer to characterize the microwave components under test. For the direct characterization of coplanar waveguide components, two-port CPW open, short and line are proposed to complement the existing calibration techniques. The developed CPW standards are characterized in the frequency range of 10 MHz to 10 GHz. As these are planar structures, effects of small superstrates on the calibration coefficients of open and short are studied also. The CPW line has shown slight changes in impedance due to superstrates, whereas a few calibration coefficients of open and short standards showed dependence on superstrates. Similar observations are noted by improving the polynomial models of CPW open and short standards up to fifth and sixth order, respectively, which better matches for CPW standards. The reported results are helpful to estimate any change in the measurement uncertainty on using such calibration standards due to superstrates.     

基于囚禁离子的微波频标研究进展

微波频标在卫星导航、精密计量、电力、通信等众多领域得到广泛应用,发挥了不可或缺的重要作用。近些年,国际上多家科研单位都在开展新型微波频标的研究,其中基于囚禁离子的微波频标具有高性能和小型化等优势,成为倍受关注的新一代微波频标。本文综述了离子阱微波频标的国内外研究现状,介绍了Penning阱和Paul阱两种常见离子阱的工作原理,以及¹⁹⁹Hg⁺,¹¹³Cd⁺,¹⁷¹Yb⁺等离子微波频标的研究动机、应用领域、技术方案和实现的技术指标。最后,本文对离子阱微波钟在守时钟、星载钟等方面的应用前景进行了展望。     

Analytic expression of the error in a linear estimator of discrepancies between time scales

An analytic dependence of the error of a linear estimator of the nonstationary random process of discrepancies between time scales in filtration, extrapolation, interpolation, and approximation from the values of the characteristics of the frequency stability of standards, the precision characteristics of instruments used in the measurement of discrepancies between time scales, the number of measurements, and algorithms used to process the results of these measurements are obtained. Translated from Izmeritel’naya Tekhnika, No. 1, pp. 28–31, January, 2009.     

Standard basis of the State Service for Time and Frequency of Russia

The structure of the standard time and frequency basis of the State Service for Time and Frequency (SSTF) of Russia is described. Information is given for the equipment make-up for the state primary standard of time and frequency (STFS) of the Russian Federation and secondary standards (SS) of the STFS. The most important metrological characteristics of the STFS and SS are provided.Translated from Izmeritelnaya Tekhnika, No. 1, pp. 12–18, January, 2005     

The choice of the optimum frequency band in correlation measurements of variable time delay

Algorithms for choosing the optimum bandwidth and integration interval T when constructing the cross-correlation function of signals from moving objects are proposed. The fundamental features of the behavior of the optimum interval T and the optimum frequency band as a function of the parameters of motion of the object are considered. Translated from Izmeritel’naya Tekhnika, No. 12, pp. 34–40, December, 2008.     

Analysis of an automatic phase adjustment system for the output signal of a quantum group frequency and time keeper

An phase locked loop (PLL) system for the output signal of a quantum group frequency and time keeper is studied. A mathematical model of an PLL system is constructed and recommendations are provided for optimizing its parameters. __________ Translated from Izmeritel’naya Tekhnika, No. 3. pp. 21–26, March, 2008.     

多通道双混频时差测量系统的实现

基于双混频时差技术设计研制了8通道的频率稳定度测量系统,实现了对8路5 MHz或10 MHz频率标准的测量.当频率为10 MHz取样时间为1 s时,系统噪声本底优于2.0 X 10~(-13),取样时间为1000 s时,系统噪声本底优于2.5×10~(-16).不但可以满足原子时标基准原子钟组的内部比对,也可实现对一般频率标准的检定和校准.     

An analysis of the errors in checking the working standards of frequency deviation by indirect measurements

The errors in checking the working standards and frequency derviation—the K2-38 equipment—by indirect measurements are analyzed. Translated from Izmeritel'naya Tekhnika, No. 10, pp. 49–53, October, 1999.     

拉线传感器变角度工作条件下的校准

为了解决静强度变形测量试验中,拉线传感器两维角度偏转引入的测量问题,采用转台提供标准偏转角度、拉线传感器正交安装测试的方法,突破了变角度工作条件下的拉线传感器校准技术,提出了基于正交安装的灵敏度系数校准方法,构建了校准装置,并通过两个正交方向的灵敏度系数合成,提出了拉线传感器正交误差模型的建立方法,最终为拉线传感器变角度工作条件下的现场误差测算提供了方案,实现了静强度试验中变形量测量的快速评定。拉线传感器校准方法的探索,对其在测试领域的应用起到了促进作用。     

Statistical and Dynamic Processing of Data Obtained When Handling Time and Frequency Standards

Methods of processing data acquired during the reproduction and conservation of time and frequency standards are considered. An algorithm is proposed for obtaining optimal estimates of the state vector of a standard in the data accumulation mode.     

Frequency strain gage transducers with constant supply voltage of the measuring circuit

An analysis of existing frequency converters of the parameters of resistance transducers is presented. Particular attention is devoted to frequency strain gage transducers with constant measuring circuit supply voltage. The advantages and drawbacks of such devices are demonstrated. Variant designs of transducers that produce a decrease in the influence of different destabilizing factors are proposed. __________ Translated from Izmeritel’naya Tekhnika, No. 5, pp. 22–26, May, 2008.     

New Special Standards of the Frequency Deviation Unit and the Amplitude Modulation Coefficient Unit

The main technical characteristics of special standards for a frequency deviation unit and for an amplitude modulation coefficient unit are provided. Features of their design and application are given.Translated from Izmeritel’naya Tekhnika, No. 3, pp. 38–40, March, 2005.     

Atomic Time and Frequency Standards Development at Shanghai Observatory, China

The performance characteristics of several types of our atomic frequency standards are described. All of these standards are designed, developed, and fabricated in China. The hydrogen maser is the only type developed by the Shanghai Observatory. This paper also describes briefly the basic consideration for system implementation, calculation approach, and experiment results in the generation of the Shanghai Observatory atomic time scale AT(SO). Based on available frequency standards-one prototype laboratory model of cesium clock, three hydrogen clocks, and several (3-6) rubidium clocks-the AT(SO) was established in 1978. The laboratory cesium clock is used to provide the basic calibration reference of the second in 1979, while hydrogen clocks and rubidium clocks are used as the working clocks to ensure the continuity of the time scale.     

The N5-4 high-frequency voltage calibrator

The main characteristics, constructional features, and recommendations on the use of a new measuring instrument, employed as a highly stable multivalued standard of a variable high-frequency voltage, operating in the 0.1–50 MHz frequency band and at voltages of 0.166–30 V, are described. __________ Translated from Izmeritel’naya Tekhnika, No. 3, pp. 40–43, March, 2008.