Recent measurements using acoustic gas thermometry have determined the value of Boltzmann constant, k, with a relative uncertainty less than 1 × 10−6. These results been supported by measurement 1.9 10−6 made dielectric-constant thermometry. Together, meet requirements International Committee for Weights and Measures enable them to proceed redefinition kelvin in 2018. In further support, we provide new determination k purely electronic approach, Johnson noise thermometry, which thermal power...

Johnson noise thermometers infer thermodynamic temperature from measurements of the thermally-induced current fluctuations that occur in all electrical conductors. This paper reviews status thermometry and its prospects for both metrological practical applications industry. The review begins with a brief description foundations principles before outlining many different techniques technological breakthroughs have enabled application to high-accuracy, cryogenic, industrial thermometry....

This paper presents a novel artificial potential field method for obstacle avoidance and path planning of mobile robots. By analyzing the shortcoming methods robot planning, we propose an based on gravity chain. Suppose that there is rubber band which connects with beginning ending in space. As will be role power, can build model to simulate shape band. Then this generate steer angle tangent instead field. putting effective information into through chain, solve problems often converges local...

The joule balance experiment has been carried out at the National Institute of Metrology, China (NIM) since 2007. By end 2013 first generation (NIM-1) achieved a measurement uncertainty 7.2 × 10−6 (k = 1). To reduce further, next apparatus (NIM-2) system is under construction. A new coil using ferromagnetic material being adopted in NIM-2 to self-heating coils. However, effects on mutual inductance from nonlinearity and hysteresis will bring considerable uncertainty. Inspired by watt...

A self-calibration method is proposed for determining the current ratio DC devices. To demonstrate feasibility of proposal, an experimental test with nominal ratios 10:1 100:1 and 1000:1 performed, a three-step calibration procedure used: Firstly, eleven magnetic modulator-based transducers (DCCTs) are used to realize through reference method; secondly, DCCTs series-parallel achieve build-up from 100:1; finally, another DCCT auxiliary calibration, combining two steps before. The merit that...

In the pulse-driven ac Josephson voltage standard, low frequency (LF) component of a drive signal increases system complexity and induces unwanted voltages through on-chip inductances. A novel zero compensation (ZC) method for waveform synthesis is presented in this paper. pulse train obtained two-level Δ-Σ modulation then reconstructed by replacing each with three pulses negative-positive-negative pattern. The amplitudes are carefully adjusted so that positive junctions to first quantum...

This paper introduces an innovative differential sampling technique for calibrating AC waveforms, leveraging a commercially available 16-bit digital-to-analog converter (DAC) as the reference standard. The novelty of this approach lies in its enhanced stability over traditional direct methods, especially frequency waveform increases. Notably, provides cost-effective sampler alternative to methods that rely on programmable Josephson voltage standard (PJVS). A critical aspect methodology is...

Minimizing the crest factor of a multitone waveform helps to increase signal noise ratio in measurement and decrease nonlinear distortions. This paper uses ac Josephson voltage standard synthesize waveforms L <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">∞</sub> algorithm optimize harmonic phases thus minimize factor. In optimization, both random Schroeder are adopted as initial for algorithm. With minimized, operating margin is increased...

A programmable Josephson voltage standard (PJVS) can be used to generate a precision square wave for induced compensation measure the mutual inductance between coils in joule balance. In this paper, influence of transitions quantized voltages synthesized waves is analyzed detail. The ratio time-integrated value total waveform reduced several parts 104 improve measurement accuracy. different configurations integrating digitizer discussed. result shows that when are quantum state, agreement...

This paper introduces the evolvement rule of Cellular Automata (CA) into robot soccer competition and combines CA with Ant Colony Algorithm, then utilizes them to help avoid obstacles. In order local convergence algorithm, we present a pheromone-diffusion mechanism target distance stimulating factor increase guidance quality ant colony in optimization, so that improve algorithm's accuracy speed. Then, utilize arc spline smooth feasible path. Finally, simulation results prove effectiveness...

Focusing on the actual situation of acquiring and dealing with speech signal in harsh environment, this article introduced FPGA-based high-speed multichannel data acquisition system design. The utilized FPGA as Core Chips for Control System to achieve A/D acquisition, transmission, abstract storage USB chip control. Experimental results presented that could complete mass storage, communication function between USB2.0 upper monitor.

Behavior models of electronic components are critical in many metrological and measurement areas. This paper uses a two-tone signal synthesized by the pulse-driven ac Josephson voltage standard to achieve input/output behavior nonlinear amplifier. Three Volterra series including memory polynomial model, general dynamic deviation reduction model analyzed compared detail. The result demonstrates high performance achieved mathematical models.

Different from the noise thermometer in a substitution configuration, superposition configuration allows reference signal to be injected into sense resistor so that thermal voltage and can simultaneously transferred measurement electronics through same transmission line. The construction of quantum-voltage-calibrated is presented this paper preliminary experiments are conducted demonstrate its feasibility for temperature measurements. A polynomial fitting used fit transfer function...

The effect of phase jitter on differential sampling using the programmable Josephson voltage standard (PJVS) system is studied in this paper. A model established for measured signal, and compensation coefficients removal are derived three different post-processing methods based discrete Fourier transform algorithm (DFT). Based our analysis, determined by angle distribution harmonic order. Furthermore, after analyzing simulating various common distributions, have been verified. simulation...

Optimizing the harmonic phases of a multitone waveform to achieve lower crest factor is beneficial reduce distortions generated by nonlinear electronic components and increase signal noise ratio in precision measurements. This paper uses two clipping algorithms minimize factor, which take less time for calculations compared Chebyshev approximation algorithm. With optimization, minimized about 1.4 both Schroeder random waveforms. Moreover, maximum tone amplitude increased significantly when...

Since 2010 we have been developing a quantum-voltage-calibrated Johnson noise thermometer at NIM to measure the Boltzmann constant k. With recent improvements in grounding and shielding of electronics, matching sources transmission lines, effects electromagnetic interference variations fitting parameters with different bandwidths were greatly reduced. By combining 14 measurements about 10 hours integrating period for each measurement, relative standard uncertainties 6.5×10 <sup...

Quantum voltage noise source (QVNS) based Johnson thermometer (JNT) system employing Josephson junctions (JJs) to generate calculable and quantum accurate pseudo-noise waveform as an artificial in measuring the thermodynamic temperature of a resistor. In this paper, we present design, fabrication, primarily characterization QVNS chip NIM.

We calibrate a commercial thermal transfer standard Fluke 792A with pulse-driven ac Josephson voltage containing 6400 junctions. The ac-dc difference of the is presented for frequencies ranging from 2 kHz to 100 10 mV applied 22 range and 220 range. Calibration uncertainties are also estimated in detail.

Behavior models of electronic components are critical in many metrological and measurement areas, e.g., time-domain simulations for analog-integrated circuit design predistortion the amplifier to reduce distortion. This paper describes use pulse-driven ac Josephson voltage standard (ACJVS) synthesize quantum accurate waveforms with ultralow distortion noise floor model nonlinearity, which is a promising way increase modeling accuracy. Four Volterra series including memory polynomial three...

This paper proposes a fully differential superposition Johnson noise thermometer to improve the robustness of system electromagnetic interference (EMI). The single-ended reference source and/or preamplifiers in previous works are replaced with signal and preamplifiers, respectively, leading significant improvement common-mode rejection EMI. new structure provides much cleaner spectrum which is importance practical industrial applications. We also develop resistance measurement unit (RMU)...

A Johnson noise thermometer (JNT) determines the thermodynamic temperature through cross-correlation measurement of in a sense resistor at an unknown temperature. In quantum voltage calibrated JNT system, superconductive source (QVNS) is required to produce artificial pseudo-random calibrate gain electronics. this paper, we present design, fabrication, and characterization QVNS chip. Compared with our previous new straightforward mirror symmetric layout implemented. For layout, coplanar...

A microwave (MW) synthesizer is a key component of high-performance coherent population trapping (CPT) atomic clocks, which are competitive candidates as miniature, low-power-consumption clocks. In this work, we demonstrated and self-adaption system to satisfy the requirement short term mid-long frequency stability CPT From experimental results, absolute phase noise was measured -110 dBc/Hz at 200 Hz. The off-resonant light shift limitation for clock can achieve better than 1×10-14 based on...