The Impact of Differential Mode Delay on Mode-Division Multiplexed Coherent Optical OFDM Transmission

2012 ◽  
Author(s):  
Adriana Lobato ◽  
Filipe Ferreira ◽  
Beril Inan ◽  
Maxim Kuschnerov ◽  
Dirk van den Borne ◽  
...  
Keyword(s):  
Differential Mode ◽  
Optical Ofdm ◽  
The Impact

scholarly journals DM Noise Estimation and DM EMI Filter Design for Interleaved Boost PFC Converters

2021 ◽  
Author(s):  
Naser Nourani Esfetanaj ◽  
Huai Wang ◽  
Frede Blaabjerg ◽  
Pooya Davari
Keyword(s):  
Filter Design ◽  
Equivalent Circuit Model ◽  
Phase Shifting ◽  
Switching Frequency ◽  
Differential Mode ◽  
Good Efficiency ◽  
Component Size ◽  
Filter Size ◽  
Emi Filter ◽  
The Impact

Interleaved power factor correction (PFC) is widely used circuit topology due to good efficiency and power density for single-switch boost PFC. As the differential mode (DM) electromagnetic interference (EMI) noise magnitude depends upon the input current ripple, this research details a comprehensive study of DM EMI filter design for interleaved boost PFC with the aim of minimizing the component size. It is also demonstrated that the different numbers of interleaved stages and switching frequency influence the filter attenuation requirement and, thus, the EMI filter size. First, an analytical model is derived on the basis of the Norton equivalent circuit model for the differential mode noises of interleaved boost PFC within the frequency range of 9-500 kHz. The derived model can help identify the optimal phase shifting among the interleaved boost converters in order to minimize the considered differential mode noises at the filter design frequency. So, a novel phase-shift method is developed to get a minimized attenuation required by a filter in Band B. Further, a volume optimization of the required DM filter was introduced based on the calculated filter attenuation and volumetric component parameters. Based on the obtained results, unconventional and conventional phase shifts have demonstrated a good performance in decreasing the EMI filter volume in Band B and Band A, respectively. A 2-kW interleaved PFC case study is presented to verify the theoretical analyses and the impact of phase-shifting on EMI filter size.

scholarly journals Differential Mode Noise Estimation and Filter Design for Interleaved Boost Power Factor Correction Converters

2021 ◽  
Vol 11 (6) ◽  
pp. 2716
Author(s):  
Naser Nourani Esfetanaj ◽  
Huai Wang ◽  
Frede Blaabjerg ◽  
Pooya Davari
Keyword(s):  
Power Factor ◽  
Filter Design ◽  
Power Factor Correction ◽  
Phase Shifting ◽  
Switching Frequency ◽  
Differential Mode ◽  
Good Efficiency ◽  
Filter Size ◽  
Emi Filter ◽  
The Impact

Interleaved power factor correction (PFC) is widely used circuit topology due to good efficiency and power density for single-switch boost PFC. As the differential mode (DM) electromagnetic interference (EMI) noise magnitude depends upon the input current ripple, this research details a comprehensive study of DM EMI filter design for interleaved boost PFC with the aim of minimizing the component size. It is also demonstrated that the different numbers of interleaved stages and switching frequency influence the filter attenuation requirement and, thus, the EMI filter size. First, an analytical model is derived on the basis of the Norton equivalent circuit model for the differential mode noises of interleaved boost PFC within the frequency range of 9–500 kHz. The derived model can help identify the proper phase shifting among the interleaved boost converters in order to minimize the considered differential mode noises at the filter design frequency. So, a novel phase-shift method is developed to get a minimized attenuation required by a filter in Band B. Further, a volume optimization of the required DM filter was introduced based on the calculated filter attenuation and volumetric component parameters. Based on the obtained results, unconventional and conventional phase shifts have demonstrated a good performance in decreasing the EMI filter volume in Band B and Band A, respectively. A 2-kW interleaved PFC case study is presented to verify the theoretical analyses and the impact of phase-shifting on EMI filter size.

scholarly journals Reducing Conducted Emissions at the Output of Full-Bridge DCDC Converters with High Voltage Steps

Electronics ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 1373
Author(s):  
Pablo González-Vizuete ◽  
Joaquín Bernal-Méndez ◽  
María A. Martín-Prats
Keyword(s):  
High Voltage ◽  
Low Voltage ◽  
Power Converter ◽  
Differential Mode ◽  
Common Mode ◽  
High Frequencies ◽  
Output Terminal ◽  
Lc Filter ◽  
The Impact ◽  
Conducted Emissions

In this work, we analyze the impact of output filter design techniques aimed to reduce conducted emissions at the output of a DCDC power converter. A thorough analysis, based on high-frequency circuit models of the converter, is performed to assess expected improvements offered by different design strategies. This analysis is then confronted with measurements of conducted emissions at the output of a 300 W 48 V to 12 V Phase Shift Full Bridge (PSFB) prototype. Those experimental results demonstrate that a symmetric arrangement of the output LC filter and a direct bonding of the return output terminal of the converter to chassis are effective to reduce common mode conducted emissions at the output. Those results also demonstrate that the symmetry of the output LC filter can reduce conducted emissions in differential mode at high frequencies, where common mode to differential mode conversion is the predominant contribution to differential mode noise. However, direct bonding to chassis of the return output terminal may be ineffective at high frequencies due to the parasitic inductance associated with this connection. Main conclusions drawn for this analysis are applicable in general for isolated converters with a high voltage step between high and low voltage sides. Since the techniques of reduction of conducted emissions studied here do not increase the number of filter components, they are especially suitable for applications where high power density is an important requirement, e.g., aerospace or automotive applications.

Time-domain Measurement and Analysis of Differential Mode Delay and Modal Bandwidth of Graded-Index Multimode Fiber in SDM Networks

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Ashish Malhotra ◽  
Gurmanik Kaur ◽  
Rakesh Goyal
Keyword(s):  
Time Domain ◽  
Input Pulse ◽  
Phase Changes ◽  
Differential Mode ◽  
Multimode Fibers ◽  
Graded Index ◽  
Output Time ◽  
Modal Bandwidth ◽  
The Impact ◽  
Multi Mode

AbstractA novel differential mode delay (DMD) and modal bandwidth measurement technique for a multi-mode optical fiber based on time-domain method has been proposed and analyzed. Mode-dependent loss (MDL) is known to have a detrimental impact on the capacity of multi-mode fiber systems. The bandwidth behavior of 50 μm/62.5 μm graded-index multimode fibers (GI-MMFs) is investigated by launching a temporal pulse into the fiber and measuring the output time-domain waveform to understand and characterize the effect of DMD. The baseband response is measured by observing the broadening of a narrow input pulse (time-domain measurement). This paper verifies the degradation in bandwidth due to profile distortion by the maximum radial shift (starting from the center of the fiber) and the number of steps. The impact due to DMD on GI-MMF performance has been analyzed through fiber transfer function, pulse width and phase changes.

Formation of Lunar Craters and Bright Rays as a Result of Meteorite Impacts

1962 ◽  
Vol 14 ◽  
pp. 415-418
Author(s):  
K. P. Stanyukovich ◽  
V. A. Bronshten
Keyword(s):  
Explosive Charge ◽  
The Moon ◽  
Meteorite Impacts ◽  
The Earth ◽  
Lunar Craters ◽  
The Impact

The phenomena accompanying the impact of large meteorites on the surface of the Moon or of the Earth can be examined on the basis of the theory of explosive phenomena if we assume that, instead of an exploding meteorite moving inside the rock, we have an explosive charge (equivalent in energy), situated at a certain distance under the surface.

The Geosciences Applied to Lunar Exploration

1962 ◽  
Vol 14 ◽  
pp. 169-257 ◽  
Author(s):  
J. Green
Keyword(s):  
Lunar Surface ◽  
Probable Mechanism ◽  
Point Of View ◽  
Lunar Exploration ◽  
Geological Model ◽  
Apply Geophysics ◽  
Surface Features ◽  
The Impact

The term geo-sciences has been used here to include the disciplines geology, geophysics and geochemistry. However, in order to apply geophysics and geochemistry effectively one must begin with a geological model. Therefore, the science of geology should be used as the basis for lunar exploration. From an astronomical point of view, a lunar terrain heavily impacted with meteors appears the more reasonable; although from a geological standpoint, volcanism seems the more probable mechanism. A surface liberally marked with volcanic features has been advocated by such geologists as Bülow, Dana, Suess, von Wolff, Shaler, Spurr, and Kuno. In this paper, both the impact and volcanic hypotheses are considered in the application of the geo-sciences to manned lunar exploration. However, more emphasis is placed on the volcanic, or more correctly the defluidization, hypothesis to account for lunar surface features.

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