Differential sampling of AC waveforms based on a programmable Josephson voltage standard using a high-precision sampler

Metrologia ◽  
2021 ◽  
Author(s):  
Mun-Seog Kim ◽  
Hehree Cho ◽  
Stephane Solve
Keyword(s):  
Systematic Error ◽  
High Precision ◽  
Voltage Response ◽  
Voltage Standard ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Limited Bandwidth ◽  
Response Characteristics ◽  
The Difference ◽  
Inherent Voltage

Abstract A high-precision sampler, Fluke 8588A multimeter in the sampling mode, was utilised to perform differential sampling of AC waveforms with a programmable Josephson voltage standard. The systematic error on the differential sampling, induced by the inherent voltage-response characteristics and built-in low-pass filter of the sampler, was estimated. Experimental results and numerical simulations revealed that the sampler could be used for reliable differential sampling of AC waveforms at frequencies up to several kilohertz, with an appropriate number of the voltage steps per the waveform period, when the input bandwidth was set to 3 MHz. In addition, the sampler was compared to an integrating sampler, Keysight 3458A, now widely used for differential sampling. At 62.5 Hz, a key frequency in the future on-site key comparison of the differential sampling on AC voltage, the difference in RMS-amplitude values obtained by the differential sampling using the two different samplers is approximately 150 nV/V due to the systematic error caused by the limited bandwidth of 150~kHz for the integrating sampler.

scholarly journals Detection and Reduction of Middle-Frequency Resonance for Industrial Servo with Self-Tuning Lowpass Filter

2012 ◽  
Vol 2012 ◽  
pp. 1-12 ◽  
Author(s):  
Wen-Yu Wang ◽  
An-Wen Shen
Keyword(s):  
Notch Filter ◽  
Corner Frequency ◽  
Frequency Range ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Frequency Resonance ◽  
Adaptive Notch Filter ◽  
Frequency Detection ◽  
Self Tuning ◽  
The Difference

A novel method for middle frequency resonance detection and reduction is proposed for speed control in industrial servo systems. Defects of traditional resonance reduction method based on adaptive notch filter in middle frequency range are analyzed. And the main reason is summarized as the difference between the resonance frequency and the oscillation frequency. A self-tuning low-pass filter is introduced in the speed feedback path, whose corner frequency is determined by FFT results and several self-tuning rules. With the proposed method the effective range of the adaptive filter is extended across the middle frequency range. Simulation and Experiment results show that the frequency detection is accurate and resonances during the speed steady states and dynamics are successfully reduced.

Attenuation of Gas Pulsation in a Reciprocating Compressor Piping System by Using a Volume-Choke-Volume Filter

2012 ◽  
Vol 134 (5) ◽  
Author(s):  
Boxiang Liu ◽  
Jianmei Feng ◽  
Zhongzhen Wang ◽  
Xueyuan Peng
Keyword(s):  
Characteristic Frequency ◽  
Pressure Pulsation ◽  
Natural Frequencies ◽  
Three Dimensional ◽  
Piping System ◽  
Reciprocating Compressor ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Response Characteristics ◽  
Low Pass

This paper presents an investigation of the use of a volume-choke-volume low-pass filter to achieve gas pulsation attenuation in a reciprocating compressor piping system, with a focus on its frequency response characteristics and influence on the actual attenuation effects. A three-dimensional acoustic model of the gas pulsation was established for a compressor discharge piping system with and without the volume-choke-volume filter, based on which the gas column natural frequencies of the piping system and the pressure wave profiles were predicted by means of the finite element method. The model was validated by comparing the predicted results with the experimental data. The results showed that the characteristic frequency of the filter was sensitive to both diameter and length of the choke but independent of the parameters of the piping beyond the filter. It is worth noting that the characteristic frequency of the filter constituted one order of the gas column natural frequencies of the piping system with the filter. The pressure pulsation levels in the piping system downstream of the filter could be significantly attenuated especially for the pulsation components at frequencies above the filter’s characteristic frequency. The measured peak-to-peak pressure pulsation at the outlet of the filter was approximately 61.7% lower than that of the surge bottle with the same volume.

Mode Decision Strategy for I-Frames in H.264/AVC Based on Low-Pass Filter

2011 ◽  
Vol 460-461 ◽  
pp. 810-815
Author(s):  
Huan Chang Qin
Keyword(s):  
Original Data ◽  
Mode Decision ◽  
Front Part ◽  
Decision Strategy ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Complicated Process ◽  
Low Pass ◽  
Data Partitions ◽  
The Difference

For the purpose of reduce the complicated process of H.264/AVC standard, the overall coding flow is studied, and some of the key technolies are discussed in the front part of this thesis. An algorithm for determining the distortion for different data partitions in H.264/AVC is proposed. A low-pass filter is implemented for each macroblock; after the macroblock is smoothed by this filter we compare the result of the filtered macroblock with the original data and generate the difference between them. Then the basic candidate-mode class is determined based on the difference, and the further mode decision can be made within this sub-class. So that the number of candidate modes is reduced, and the complexity of I-frame mode decision process is reduced.

Design of Dual High Precision Power Signal Generator Based on AD9854

2014 ◽  
Vol 568-570 ◽  
pp. 344-348
Author(s):  
Ru Sen Fan ◽  
Yong Wang ◽  
Jun Jie Yang ◽  
Zhi Wang
Keyword(s):  
High Precision ◽  
High Power ◽  
Duty Cycle ◽  
Signal Generator ◽  
Numerical Control ◽  
Signal Frequency ◽  
Direct Digital Synthesis ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Square Wave

To obtain the dual high-precision numerical control signal source, and could be accurately adjusted the dual signals frequency and phase and increase the output signal power, the paper presented a method based on direct digital synthesis technology and parallel push-pull output, designed and implemented the dual channel high-precision and high power signal generator. MSP430 controlled AD9854 registers to realize frequency and phase modulation, after low-pass filter to adjust the square wave duty cycle by the DAC7612, amplitude was integrated optimization adjustment by AD9854 AD603 and power amplifier. Consideration the anti-jamming measures, the system is stable and reliable, and can output high-precision and high power sine and square wave in the 5-150kHz frequency band, signal frequency, phase, amplitude and duty cycle can numerical control. In addition, it has sweep output mode.

Experimental Study of Slam Forces on External Turrets With Different Top Angles

2020 ◽  
Author(s):  
Yuki Ishihara ◽  
Motohiko Murai ◽  
So Nakanishi ◽  
Shunji Kato ◽  
Yasuharu Nakajima
Keyword(s):  
Extreme Values ◽  
Probability Distributions ◽  
Rayleigh Distribution ◽  
Model Tests ◽  
Validity And Reliability ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Low Pass ◽  
Generalized Pareto Distributions ◽  
The Difference

Abstract The external turret is widely used for mooring FPSOs. However, external turrets can be exposed to slamming and it leads to generate FPSO’s whipping. To analyze the fatigue strength of the FPSOs, probability distributions of slam forces acting when slamming happens are necessary. In this study, we focus on slam force filtered by 10Hz low-pass filter. Then, we examined the probability distribution of peak slam forces, the effect of the top angle on slam forces, and the difference of two types (fixed and oscillator-mounted) tests. For three turret models with different top angle (180°, 160°, and 140°), two types of model tests were carried out. To confirm the experiment’s validity and reliability, we compared these model tests with the previous study. The slam forces measured on a conical (140°) turret were consistent with the estimated curve in the previous study. The comparison of two types of tests indicated that fixed turret tests were an easy and valid way of measuring the slam forces on external turrets. 3-hour return values calculated by five methods were used to examine the characteristic of each turret. And these values were compared with 3-hour mean maxima to examine the difference between the five methods and experimental results. As a result, the use of Generalized Extreme Values and Generalized Pareto distributions is more suitable than using Rayleigh distribution in estimating return values of slam forces on external turrets.

scholarly journals New Photoplethysmographic Signal Analysis Algorithm for Arterial Stiffness Estimation

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Kristjan Pilt ◽  
Rain Ferenets ◽  
Kalju Meigas ◽  
Lars-Göran Lindberg ◽  
Kristina Temitski ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Arterial Stiffness ◽  
Regression Line ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Significance Level ◽  
Analysis Algorithm ◽  
Low Pass ◽  
The Difference ◽  
Diabetes Patients

The ability to identify premature arterial stiffening is of considerable value in the prevention of cardiovascular diseases. The “ageing index” (AGI), which is calculated from the second derivative photoplethysmographic (SDPPG) waveform, has been used as one method for arterial stiffness estimation and the evaluation of cardiovascular ageing. In this study, the new SDPPG analysis algorithm is proposed with optimal filtering and signal normalization in time. The filter parameters were optimized in order to achieve the minimal standard deviation ofAGI, which gives more effective differentiation between the levels of arterial stiffness. As a result, the optimal low-pass filter edge frequency of 6 Hz and transitionband of 1 Hz were found, which facilitatesAGIcalculation with a standard deviation of 0.06. The study was carried out on 21 healthy subjects and 20 diabetes patients. The linear relationship(r=0.91)between each subject’s age andAGIwas found, and a linear model with regression line was constructed. For diabetes patients, the meanAGIvalue difference from the proposed modelyAGIwas found to be 0.359. The difference was found between healthy and diabetes patients groups with significance level ofP<0.0005.

A New Parabolic Sliding Mode Filter Augmented by a Linear Low-Pass Filter and Its Application to Position Control

2017 ◽  
Vol 140 (4) ◽  
Author(s):  
Myo Thant Sin Aung ◽  
Zhan Shi ◽  
Ryo Kikuuwe
Keyword(s):  
Position Control ◽  
Sliding Mode ◽  
Frequency Noise ◽  
Noise Attenuation ◽  
Optical Encoder ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Response Characteristics ◽  
Low Pass ◽  
Dc Servomotor

This paper proposes a new sliding mode filter augmented by a linear low-pass filter (LPF) for mitigating the effect of high-frequency noise. It is based on the derivation of three new variants of Jin et al.'s (2012, “Real-Time Quadratic Sliding Mode Filter for Removing Noise,” Adv. Rob., 26(8–9), pp. 877–896) parabolic sliding mode filter (J-PSMF) and investigation on their frequency-response characteristics. The new filter is developed by augmenting one of the variants of J-PSMF by a second-order linear LPF. It has better balance between the noise attenuation and signal preservation than both linear LPFs and J-PSMF. The effectiveness of the new filter is experimentally evaluated on a direct current (DC) servomotor equipped with an optical encoder. This paper also shows the application of the proposed filter to a positioning system under PDD2 (proportional, derivative, and second derivative) control, which successfully realizes the noise attenuation and the nonovershooting response simultaneously.

Mono-Objective Optimization of a Photovoltaic Tracking System with LPF Controllers

2016 ◽  
Vol 823 ◽  
pp. 7-12
Author(s):  
Cătălin Alexandru
Keyword(s):  
Control System ◽  
Tracking System ◽  
Photovoltaic System ◽  
Design Parameters ◽  
Energetic Efficiency ◽  
Pass Filter ◽  
Low Pass Filter ◽  
External Loop ◽  
Solar Tracker ◽  
The Difference

The work deals with the optimal design of a single-axis solar tracker, which is used to adjust the daily position of a photovoltaic system in order to capture as much as possible solar radiation. The two main components of the solar tracker (the mechanical device and the control system) have been coupled (integrated) in the concurrent engineering concept. For assuring high stability and robustness, the control system is a cascaded two-loop employing LPF (Low-Pass Filter) controllers. The controlled parameter in the main (external) loop is the daily angle of the photovoltaic platform, while in the secondary (internal) loop the linear velocity in the driving actuator is monitored. The mono-objective optimization problem is described in the following way: to minimize the difference between the imposed and current daily angle (thus preserving a high energetic efficiency of the tracking system), considering the controllers’ gains as independent design parameters.

Analysis of a Novel SAW Acceleration Sensor with Cantilever Beam Using ST-X Quartz

2012 ◽  
Vol 189 ◽  
pp. 285-289 ◽  
Author(s):  
Hua Jiang ◽  
Wen Ke Lu ◽  
Yuan Yuan Li ◽  
Shi Gen Shen
Keyword(s):  
Cantilever Beam ◽  
Lateral Acceleration ◽  
The Novel ◽  
Acceleration Sensor ◽  
Temperature Drift ◽  
Element Analysis ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Article Analysis ◽  
The Difference

In order to improve the signal-noise rate (SNR) of the acceleration sensor system, this article analysis of the design principles of a novel surface acoustic wave (SAW) acceleration sensor with cantilever beam using ST-X quartz. The main structure of the novel SAW acceleration sensor is composed of two oscillator, a mixer and a low pass filter to get the difference frequency structure, which can inhibit temperature drift and lateral acceleration impact. The two oscillator have the same structure, which is constitute of a low insertion loss SAW delay line and a feedback amplifier. This article shows the simulation results of the force analysis of the cantilever beam free end using ANSYS finite element analysis software. The novel acceleration sensor has potential applications in portable mobile devices or automotive airbags fields.

scholarly journals Improvement of Statistical Performance of Ordinal Multiscale Entropy Techniques Using Refined Composite Downsampling Permutation Entropy

Entropy ◽  
2020 ◽  
Vol 23 (1) ◽  
pp. 30
Author(s):  
Antonio Dávalos ◽  
Meryem Jabloun ◽  
Philippe Ravier ◽  
Olivier Buttelli
Keyword(s):  
Theoretical Perspective ◽  
Original Method ◽  
The Other ◽  
Multiscale Entropy ◽  
Permutation Entropy ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Theoretical Predictions ◽  
Low Pass ◽  
The Difference

Multiscale Permutation Entropy (MPE) analysis is a powerful ordinal tool in the measurement of information content of time series. MPE refinements, such as Composite MPE (cMPE) and Refined Composite MPE (rcMPE), greatly increase the precision of the entropy estimation by modifying the original method. Nonetheless, these techniques have only been proposed as algorithms, and are yet to be described from the theoretical perspective. Therefore, the purpose of this article is two-fold. First, we develop the statistical theory behind cMPE and rcMPE. Second, we propose an alternative method, Refined Composite Downsampling Permutation Entropy (rcDPE) to further increase the entropy estimation’s precision. Although cMPE and rcMPE outperform MPE when applied on uncorrelated noise, the results are higher than our predictions due to inherent redundancies found in the composite algorithms. The rcDPE method, on the other hand, not only conforms to our theoretical predictions, but also greatly improves over the other methods, showing the smallest bias and variance. By using MPE, rcMPE and rcDPE to classify faults in bearing vibration signals, rcDPE outperforms the multiscaling methods, enhancing the difference between faulty and non-faulty signals, provided we apply a proper anti-aliasing low-pass filter at each time scale.

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