scholarly journals Measurements of Sonic Boom with Limited Frequency‐Response Instrumentation—A Theoretical Study

1966 ◽  
Vol 39 (6) ◽  
pp. 1251-1251
Author(s):  
Malcolm J. Crocker ◽  
Louis C. Sutherland
Keyword(s):  
Frequency Response ◽  
Theoretical Study ◽  
Sonic Boom ◽  
Limited Frequency

Employing digital pole-shifting filters to improve low-frequency response of sonic boom measurements

2019 ◽  
Vol 146 (4) ◽  
pp. 2754-2754
Author(s):  
Reese D. Rasband ◽  
Kent L. Gee ◽  
Thomas B. Gabrielson ◽  
Alexandra Loubeau
Keyword(s):  
Frequency Response ◽  
Low Frequency ◽  
Sonic Boom

scholarly journals Overvoltages and Transients Identification In On-line Bushing Monitoring

2020 ◽  
Vol 69 (3) ◽  
Author(s):  
Wieslaw Gil ◽  
Wiktor Masłowski ◽  
Przemysław Wronek
Keyword(s):  
Frequency Response ◽  
Support Service ◽  
Monitoring Systems ◽  
Resonance Phenomena ◽  
Limited Frequency ◽  
On Line ◽  
High Dynamics

Overvoltages and transients are sometimes recognized as the cause of bushings’ rapid failure. This fact is confirmed by the studies published at the 2018 CIGRE session. They can also initiate dangerous resonance phenomena in transformer windings. The identification of very fast overvoltages characterized by high dynamics of voltage changes, so-called "transients", is difficult due to the limited frequency response of station voltage transformers. However, the bushing monitoring systems, based on the so-called "voltage method" can be used for this purpose successfully. There are several running bushing monitoring systems based on this method in Poland. The transients’ events are registered together with their oscillographs in Transformer Monitoring Systems (TMS). The overvoltage statistics are also performed to support service procedures.The TMS are integrated with station systems, which greatly increases the possibility of overvoltages phenomena analyzing.

An Alternative Approach to Substructuring in Vibratory Systems Containing Soft Rubber Isolators

2019 ◽  
Vol 141 (6) ◽  
Author(s):  
Viviane Cassol Marques ◽  
Michael John Brennan
Keyword(s):  
Frequency Response ◽  
Complete System ◽  
Finite Element Models ◽  
Frequency Range ◽  
Vibratory Response ◽  
Alternative Approach ◽  
Speed Up ◽  
Limited Frequency ◽  
Rubber Isolator ◽  
Soft Rubber

Abstract Built-up structures, such as airplanes, ships, and even refrigeration systems, which have many components, can be substructured to speed up and facilitate the process of calculating the vibratory response of the complete system. In many structures, there are rubber isolators that connect component parts, and these connections can each occur over a finite distributed area. It is often convenient and intuitive to substructure the system at the isolators. However, in previous work, it has been shown that the frequency response of the complete system does not always agree with the frequency response of the system calculated from the mobilities of the subsystems. It was thought that this was due to the distributed area connection of the isolators, and this motivated the study reported in this article. An investigation into some issues that occur when substructuring a system that contains soft distributed isolators is described. Using finite element models, it is shown that if a system is substructured, such that the interface between the substructures occurs at a soft rubber isolator, then there is a limited frequency range over which the frequency response function of the assembled system is accurate. It is further shown that it is far better to substructure the system, at stiff, discrete connections, if possible. The frequency range over which the frequency response of the assembled system should then be more accurate over a much wider frequency range.

scholarly journals Research and optimization of a new design of output window for high power microwave tubes

2019 ◽  
Vol 30 ◽  
pp. 02004
Author(s):  
Anatoly Galdetskiy ◽  
Alexander Savin
Keyword(s):  
Electric Field ◽  
Frequency Response ◽  
High Power ◽  
Theoretical Study ◽  
Optimized Design ◽  
Output Window ◽  
High Power Microwave ◽  
Critical Areas ◽  
Power Microwave

A design of an output window integrated with an output resonator of the high-power klystron is proposed. The results of a theoretical study of the frequency response of an integrated window are presented. Calculation of the electric field in critical areas of the optimized design showed that the losses in the vacuum-tight dielectric are much lower, and the tangential components of the field on its surface, which are the source of breakdowns, are lower or comparable with similar parameters of traditional pillbox windows.

scholarly journals Acousto-Optic Comb Interrogation System for Random Fiber Grating Sensors with Sub-nm Resolution

Sensors ◽  
2021 ◽  
Vol 21 (12) ◽  
pp. 3967
Author(s):  
Dragos A. Poiana ◽  
Jose A. Garcia-Souto ◽  
Xiaoyi Bao
Keyword(s):  
Frequency Response ◽  
Acoustic Waves ◽  
Frequency Comb ◽  
Surface Acoustic Waves ◽  
Fiber Grating ◽  
Phase Detection ◽  
Limited Frequency ◽  
Small Cracks ◽  
Non Destructive

The broad-frequency response and nanometer-range displacements of ultrasound detection are essential for the characterization of small cracks, structural health monitoring and non-destructive evaluation. Those perturbations are generated at sub-nano-strain to nano-strain levels. This corresponds to the sub-nm level and, therefore, to about 0.1% of wavelength change at 1550 nm, making it difficult to detect them by conventional interferometric techniques. In this paper, we propose a demodulation system to read the random fiber grating spectrum using a self-heterodyne acousto-optic frequency comb. The system uses a self-heterodyne approach to extract phase and amplitude modulated signals to detect surface acoustic waves with sub-nanometer amplitudes in the frequency domain. The method can detect acoustic frequencies of 1 MHz and the associated displacement. The system is calibrated via phase detection with a heterodyne interferometer, which has a limited frequency response of up to 200 kHz. The goal is to achieve sub-nanometer strain detection at MHz frequency with random fiber gratings.

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