scholarly journals A review of accurate phase measurement methods and instruments for sinewave signals

ACTA IMEKO ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 52
Author(s):  
Eulalia Balestrieri ◽  
Luca De Vito ◽  
Francesco Picariello ◽  
Sergio Rapuano ◽  
Ioan Tudosa
Keyword(s):  
Measurement Uncertainty ◽  
High Frequency ◽  
Measurement Method ◽  
Essential Role ◽  
Scientific Literature ◽  
Phase Measurement ◽  
Measurement Methods ◽  
Frequency Range ◽  
Electronic Instrumentation ◽  
Response Testing

<p class="Abstract">The phase measurement of sinewave signals is important in  several applications, such as electric and electronic instrumentation; telecommunications; and optical interferometry. The uncertainty of the phase measurement has an essential role in ensuring the suitable performance of the devices and systems used by the relevant application. Some highly accurate phase measurement methods have been developed and implemented in different instrument types that are currently available on the market or have been proposed in the scientific literature, each capable of covering very different frequency ranges. This article presents an overview of these methods and instruments in order to highlight the characteristics in terms of the measurement uncertainty of the main methods and instruments that are used, by taking into account a varying operative frequency range. The standard deviations considered in the surveyed literature are used to identify a phase measurement method that is capable of covering a large high-frequency range, simultaneously maintaining a low value of measurement uncertainty, as requested by some applications (like waveform recorder frequency response testing).</p>

Analysis of the Pitch Diameter Measurement Based on Three-Pin/T-Shaped Probe and Thread Scanner

2014 ◽  
Vol 644-650 ◽  
pp. 1307-1312
Author(s):  
Yu Zhang ◽  
Yue Wang ◽  
Xing Yu Yao
Keyword(s):  
Experimental Data ◽  
Measurement Uncertainty ◽  
Measurement Method ◽  
Measurement Methods ◽  
Data Consistency ◽  
Maximum Difference ◽  
Diameter Measurement ◽  
Application Program ◽  
Actual Size ◽  
Methods Of Measurement

To study the data consistency of Three-pin/T-shaped probe and thread scanning measurement. Through the analysis and summary of the measurement methods and experimental data obtained in two methods of measurement uncertainty can meet the thread gauge diameter measurement requirements. Experiment to obtain the maximum difference of the actual size of the corresponding point of 1.1μm, verify the correctness of the two thread measurement method and propose the appropriate application program.

scholarly journals High Frequency Modal Testing of the Multiblade Packets Using a Noncontact Measurement and Excitation System

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
C. H. Liu ◽  
C. Zang ◽  
F. Li ◽  
E. P. Petrov
Keyword(s):  
High Frequency ◽  
Measurement Method ◽  
Natural Frequencies ◽  
Spectral Lines ◽  
Modal Testing ◽  
Frequency Resolution ◽  
Mode Shapes ◽  
Finite Model ◽  
Frequency Range ◽  
Noncontact Measurement

High cycle failure of blades and vanes caused by the vibration is one of the major causes reducing the lifetime of turbomachines. For multiblade packets, the failure may occur at vibrations with high frequencies that can reach up to tens of kHz. The experimental modal testing of blades is crucial for the validation of numerical models and for the optimization of turbomachine design. In this paper, the test rig and procedure for measurements of dynamic characteristics of lightweight multiblade packets in wide and high frequency ranges are developed. The measurements are based on a noncontact excitation and noncontact measurement method, which allows the determination of the modal characteristics of the packets with high accuracy in wide frequency ranges. The responses of the multiblade packets are measured using a Scanning Laser Doppler Vibrometry (SLDV), while vibrations are excited by the acoustic excitation technique. Modal tests of the blade packet comprising 18 vane blades connected by shrouds are performed. The measurements are performed within the high frequency range of 0–30 kHz, and the natural frequencies and mode shapes are obtained for first 97 modes. To capture the complex high frequency blade mode shapes, each blade in the packet is scanned over 25 reference points uniformly distributed over the blade concave surface. In order to obtain the high frequency resolution, the frequency range used for the measurements is split into several frequency intervals accordingly to the number of spectral lines available in the used data acquisition system, and for each such interval, the test is performed separately. The finite model of the packet is created, and the numerical modal analysis is performed to compare the calculated natural frequencies and mode shapes with the experimental measurements. The comparison shows the satisfactory with those from finite element analysis. It illustrates the measurement method described in this work is effective and reliable.

Energy Absorption of Vibration in the Hand for Higher Frequencies

1996 ◽  
Vol 15 (2) ◽  
pp. 71-79 ◽  
Author(s):  
Anna SöRensson ◽  
Lage Burström
Keyword(s):  
Energy Absorption ◽  
High Frequency ◽  
Measurement Method ◽  
Vibration Energy ◽  
Frequency Range ◽  
Measurement And Analysis ◽  
Method Of Measurement ◽  
High Frequency Vibrations ◽  
Noise Vibration ◽  
Male Subjects

The aim of this study has been to develop a measurement method to study the absorption of vibration energy on exposure to high frequency vibrations. The developed measurement method consists of specially constructed equipment for measurement and analysis of the subject's absorption of vibration energy. In this study the energy absorption from the exposure to white noise vibration within the frequency-range 20 to 5000 Hz has been studied. Five female and five male subjects were involved in this study. The results show that the developed method of measurement works satisfactorily and gives reliable results for the energy absorption within the frequency-range 20 to 4000 Hz. Furthermore, the results show that the subjects absorb vibration energy even for frequencies above 1000 Hz. The results also show that the energy absorption is dependent upon factors such as gender, the level of the vibration and the frequency.

scholarly journals Effects of microwave radiation on living microorganisms: effects and mechanisms

2021 ◽  
Vol 3 (1) ◽  
pp. 75-84
Author(s):  
Tatyana N. Danilchuk ◽  
Kamal М. Alkhateeb
Keyword(s):  
High Frequency ◽  
Food Industry ◽  
Scientific Literature ◽  
Growth Parameters ◽  
Biological Effects ◽  
High Energy ◽  
Frequency Range ◽  
Vital Activity ◽  
Absorbed Energy ◽  
Microwave Exposure

The article analyzes the scientific literature on the effect of microwave exposure on the vital activity of microorganisms. The influence of the frequency of microwaves, the power of the applied impact and the total amount of absorbed energy on the viability of microorganisms and the features of their growth is considered. Possible mechanisms of interaction of microbial cells with the electromagnetic field in the ultrahigh frequency range are considered. It is noted that microorganisms die when exposed to high-energy and high-frequency microwaves, while low-energy and high-frequency microwaves contribute to the intensification of their growth. It is concluded that although many authors observe significant biological effects when exposed to microwaves on living systems, this issue has not been sufficiently studied in the scientific literature. It is of interest to conduct a systematic study of the effect of microwaves of a certain frequency on the biological, biochemical and growth parameters of the cells of microorganisms, in particular lactic acid organisms, in order to use the results of these studies in the food industry in the production of new food products.

Evaluation of Special Hearing Aids for Deaf Children

1971 ◽  
Vol 36 (4) ◽  
pp. 527-537 ◽  
Author(s):  
Norman P. Erber
Keyword(s):  
Hearing Aids ◽  
High Frequency ◽  
Hearing Aid ◽  
Low Frequency ◽  
Acoustic Stimulation ◽  
Deaf Children ◽  
Frequency Range ◽  
Frequency Limit ◽  
Unpublished Studies ◽  
Published Research

Two types of special hearing aid have been developed recently to improve the reception of speech by profoundly deaf children. In a different way, each special system provides greater low-frequency acoustic stimulation to deaf ears than does a conventional hearing aid. One of the devices extends the low-frequency limit of amplification; the other shifts high-frequency energy to a lower frequency range. In general, previous evaluations of these special hearing aids have obtained inconsistent or inconclusive results. This paper reviews most of the published research on the use of special hearing aids by deaf children, summarizes several unpublished studies, and suggests a set of guidelines for future evaluations of special and conventional amplification systems.

HIGH FREQUENCY OHMIC LOSSES IN TERAHERTZ FREQUENCY RANGE CW KLYNOTRONS

2017 ◽  
Vol 76 (10) ◽  
pp. 929-940 ◽  
Author(s):  
Yu. S. Kovshov ◽  
S. S. Ponomarenko ◽  
S. A. Kishko ◽  
A. A. Likhachev ◽  
S. A. Vlasenko ◽  
...  
Keyword(s):  
High Frequency ◽  
Terahertz Frequency ◽  
Frequency Range ◽  
Terahertz Frequency Range ◽  
Ohmic Losses

scholarly journals An Improved Time Integration Method Based on Galerkin Weak Form with Controllable Numerical Dissipation

2021 ◽  
Vol 11 (4) ◽  
pp. 1932
Author(s):  
Weixuan Wang ◽  
Qinyan Xing ◽  
Qinghao Yang
Keyword(s):  
High Frequency ◽  
Integration Method ◽  
Time Integration ◽  
Low Frequency ◽  
Weak Form ◽  
High Accuracy ◽  
Numerical Dissipation ◽  
Frequency Range ◽  
Time Integration Method ◽  
Numerical Damping

Based on the newly proposed generalized Galerkin weak form (GGW) method, a two-step time integration method with controllable numerical dissipation is presented. In the first sub-step, the GGW method is used, and in the second sub-step, a new parameter is introduced by using the idea of a trapezoidal integral. According to the numerical analysis, it can be concluded that this method is unconditionally stable and its numerical damping is controllable with the change in introduced parameters. Compared with the GGW method, this two-step scheme avoids the fast numerical dissipation in a low-frequency range. To highlight the performance of the proposed method, some numerical problems are presented and illustrated which show that this method possesses superior accuracy, stability and efficiency compared with conventional trapezoidal rule, the Wilson method, and the Bathe method. High accuracy in a low-frequency range and controllable numerical dissipation in a high-frequency range are both the merits of the method.

scholarly journals Band notched self complementaryultra wideband antenna for wireless applications

2018 ◽  
Vol 7 (2.8) ◽  
pp. 529 ◽  
Author(s):  
Ch Ramakrishna ◽  
G A.E.Satish Kumar ◽  
P Chandra Sekhar Reddy
Keyword(s):  
High Frequency ◽  
Return Loss ◽  
Wide Band ◽  
Ultra Wideband ◽  
Impedance Bandwidth ◽  
Relative Dielectric Permittivity ◽  
Frequency Range ◽  
Ground Structure ◽  
Wireless Applications ◽  
Patch Edge

This paper presents a band notched WLAN self complementaryultra wide band antenna for wireless applications. The proposed antenna encounters a return loss (RL) less than -10dB for entire ultra wideband frequency range except band notched frequency. This paper proposes a hexagon shape patch, edge feeding, self complementary technique and defective ground structure. The antenna has an overall dimensionof 28.3mm × 40mm × 2mm, builton  substrate FR4 with a relative dielectric permittivity 4.4. And framework is simulated finite element method with help of high frequency structured simulator HFSSv17.2.the proposed antenna achieves a impedance bandwidth of 8.6GHz,  band rejected WLAN frequency range 5.6-6.5 GHz with  vswr is less than 2.

Assessing bias, precision, and agreement in method comparison studies

2019 ◽  
Vol 29 (3) ◽  
pp. 778-796 ◽  
Author(s):  
Patrick Taffé
Keyword(s):  
Measurement Method ◽  
Method Comparison ◽  
Estimation Procedure ◽  
Measurement Methods ◽  
Repeated Measurements ◽  
Confidence Bands ◽  
The Other ◽  
Reference Standard ◽  
Simultaneous Confidence Bands ◽  
Index Of Agreement

Recently, a new estimation procedure has been developed to assess bias and precision of a new measurement method, relative to a reference standard. However, the author did not develop confidence bands around the bias and standard deviation curves. Therefore, the goal in this paper is to extend this methodology in several important directions. First, by developing simultaneous confidence bands for the various parameters estimated to allow formal comparisons between different measurement methods. Second, by proposing a new index of agreement. Third, by providing a series of new graphs to help the investigator to assess bias, precision, and agreement between the two measurement methods. The methodology requires repeated measurements on each individual for at least one of the two measurement methods. It works very well to estimate the differential and proportional biases, even with as few as two to three measurements by one of the two methods and only one by the other. The repeated measurements need not come from the reference standard but from either measurement methods. This is a great advantage as it may sometimes be more feasible to gather repeated measurements with the new measurement method.

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