Frequency response modelling and optimization of long wavelength RCE photodiodes

2016 ◽  
Vol 52 (1-2) ◽  
pp. 641-648 ◽  
Author(s):  
Jorge Pereira ◽  
Verónica Matos
Keyword(s):  
Frequency Response ◽  
Long Wavelength ◽  
Response Modelling ◽  
Modelling And Optimization

scholarly journals Frequency Response Modelling of Transformer Windings Connected in Parallel

Energies ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1395 ◽  
Author(s):  
Szymon Banaszak ◽  
Konstanty Marek Gawrylczyk ◽  
Katarzyna Trela
Keyword(s):  
Frequency Response ◽  
Computer Modelling ◽  
Active Part ◽  
Response Analysis ◽  
Frequency Response Analysis ◽  
Network Method ◽  
Interpretation Process ◽  
Parallel Connections ◽  
Response Modelling ◽  
Field Network

This paper describes the approach to the frequency response modelling of transformer windings consisting of coils connected in parallel. At present, computer models are intensively developed with the aim of simulating the influence of faults on the frequency response of the active part of power transformers. Frequency response analysis (FRA) is one of the standard methods used for the assessment of the mechanical condition of a transformer’s windings and core. The interpretation of the FRA results is crucial in the diagnostics of the active part of the transformer. Proper simulations of the FRA results allow the improvement and simplification of the interpretation process of the windings’ faults. Usually only serial winding wires are simulated in computer modelling and parallel wires are simplified, leading to simulation inaccuracies. In this work, a combined electromagnetic field/network method, which includes parallel connections of the coils, is proposed. The method is based on lumped RLC elements. The results of the analysis conducted by the computer model are referred to as the real transformer measurement. The modelling was also performed for the case of a winding with a fault. The results of modelling were assessed with four numerical indices used for FRA interpretation.

Dynamic Behavior of Complex Fluid-Filled Tubing Systems—Part 1: Tubing Analysis

1998 ◽  
Vol 123 (1) ◽  
pp. 71-77 ◽  
Author(s):  
Forbes T. Brown ◽  
Stephen C. Tentarelli
Keyword(s):  
Frequency Response ◽  
Dynamic Behavior ◽  
Transmission Matrix ◽  
Matrix Approach ◽  
Frequency Dependent ◽  
Long Wavelength ◽  
System Models ◽  
Analogous System ◽  
Complex Fluid ◽  
Poisson Coupling

A general transmission-matrix approach is given for finding the frequency response of linearized long-wavelength models for the vibration in systems with straight and curved fluid-filled tubes. Couplings between the fluid and wall motions include the Bourdon effect, frequency-dependent wall shear, the Poisson coupling and the effect of discontinuities. The introduction of a global transmission matrix allows nonplanar tubing systems of virtually any complexity to be analyzed, overcoming the round-off error problem that plagues the basic transmission-matrix approach for this and analogous system models. Corroborating experiments focus on the Poisson and Bourdon effects.

scholarly journals Extraction of winding parameters for 33/11 kV, 30 MVA transformer based on finite element method for frequency response modelling

PLoS ONE ◽  
2020 ◽  
Vol 15 (8) ◽  
pp. e0236409
Author(s):  
Avinash Srikanta Murthy ◽  
Norhafiz Azis ◽  
Jasronita Jasni ◽  
Mohammad Lutfi Othman ◽  
Mohd Fairouz Mohd Yousof ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Frequency Response ◽  
Response Modelling ◽  
Element Method

High frequency response of near-room temperature LWIR HgCdTe heterostructure photodiodes

2010 ◽  
Vol 18 (3) ◽  
Author(s):  
M. Kopytko ◽  
K. Jóźwikowski ◽  
A. Jóźwikowska ◽  
A. Rogalski
Keyword(s):  
Response Time ◽  
Frequency Response ◽  
High Frequency ◽  
Room Temperature ◽  
Reverse Bias ◽  
Drift Time ◽  
Long Wavelength ◽  
High Frequency Response ◽  
Multilayer Heterostructures ◽  
Theoretical Predictions

AbstractThe high frequency response of near-room temperature long wavelength infrared (LWIR) HgCdTe heterostructure photodiodes is investigated using a Fourier space method. The MOCVD HgCdTe multilayer heterostructures were grown on GaAs substrates. The response time of devices as a function of bias has been measured experimentally by using 10-μm quantum cascade laser and fast oscilloscope with suitable transimpedance amplifier. Results of theoretical predictions are compared with experimental data. It is shown that the response time at weak reverse bias condition is mainly limited by the drift time of carriers moving into π-n+ junction. Using the reverse bias higher than 50 mV, the transit time across the absorber region limits the response time. The response time of small-area devices decreases in the region of week reverse bias achieving value below 1 ns.

scholarly journals The gamma response to colour hue in humans: Evidence from MEG

PLoS ONE ◽  
2020 ◽  
Vol 15 (12) ◽  
pp. e0243237
Author(s):  
Gavin Perry ◽  
Nathan W. Taylor ◽  
Philippa C. H. Bothwell ◽  
Colette C. Milbourn ◽  
Georgina Powell ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Frequency Response ◽  
Visual Stimulation ◽  
Gamma Oscillations ◽  
Colour Space ◽  
Long Wavelength ◽  
Gamma Frequency ◽  
Full Screen ◽  
Gamma Power ◽  
Oscillatory Response

It has recently been demonstrated through invasive electrophysiology that visual stimulation with extended patches of uniform colour generates pronounced gamma oscillations in the visual cortex of both macaques and humans. In this study we sought to discover if this oscillatory response to colour can be measured non-invasively in humans using magnetoencephalography. We were able to demonstrate increased gamma (40–70 Hz) power in response to full-screen stimulation with four different colour hues and found that the gamma response is particularly strong for long wavelength (i.e. red) stimulation, as was found in previous studies. However, we also found that gamma power in response to colour was generally weaker than the response to an identically sized luminance-defined grating. We also observed two additional responses in the gamma frequency: a lower frequency response around 25–35 Hz that showed fewer clear differences between conditions than the gamma response, and a higher frequency response around 70–100 Hz that was present for red stimulation but not for other colours. In a second experiment we sought to test whether differences in the gamma response between colour hues could be explained by their chromatic separation from the preceding display. We presented stimuli that alternated between each of the three pairings of the three primary colours (red, green, blue) at two levels of chromatic separation defined in the CIELUV colour space. We observed that the gamma response was significantly greater to high relative to low chromatic separation, but that at each level of separation the response was greater for both red-blue and red-green than for blue-green stimulation. Our findings suggest that the stronger gamma response to red stimulation cannot be wholly explained by the chromatic separation of the stimuli.

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