scholarly journals Mobile free space optic nodes in single-input multiple-output setup under transmitter misalignment

2011 ◽  
Vol 11 (12) ◽  
pp. 1540-1550 ◽  
Author(s):  
Hassan Moradi ◽  
Hazem H. Refai ◽  
Peter G. LoPresti ◽  
Mohammed Atiquzzaman
Keyword(s):  
Free Space ◽  
Free Space Optic ◽  
Input Multiple Output ◽  
Single Input

scholarly journals Free Space Optic Receiver with Strongly Overlapped Photodetectors’ Field of View

2019 ◽  
Vol 9 (2) ◽  
pp. 343 ◽  
Author(s):  
Karel Witas ◽  
Jan Nedoma
Keyword(s):  
Free Space ◽  
Additive Noise ◽  
Noise Suppression ◽  
Signal To Noise Ratio ◽  
Optical Channel ◽  
Electrical Signals ◽  
Free Space Optic ◽  
Input Multiple Output ◽  
Single Input ◽  
Areas Of Interest

In this study, we designed a mobile free space optic receiver that uses several photodetectors to provide omnidirectional receiving capability. Assuming only one transmitter, it is a receiver which builds a single input multiple output optical channel. The photodetectors are fixed to truncated pyramid walls. Electrical signals from the photodetectors are processed using an equal gain combining technique. This architecture allows simple circuits and enables additive noise suppression. The minimum angle between the pyramid base and the direction of falling rays was calculated to determine the threshold for additive noise suppression. Two areas of interest presented themselves: the processing of very weak electrical signals often drowned in noise, and optimization of the number of photodetectors whose fields of view overlapped strongly. We outline the design of the optical receiver circuitry and provide some practical hints concerning its assembly. The receiver was evaluated using bit error rate measurements and comparing signal-to-noise ratio parameters for various photodetector numbers. The measured data confirm the theoretical assumptions.

Performance analysis of WDM free space optics transmission system using MIMO technique under various atmospheric conditions

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Kavitha Thandapani ◽  
Maheswaran Gopalswamy ◽  
Sravani Jagarlamudi ◽  
Naveen Babu Sriram
Keyword(s):  
Wavelength Division Multiplexing ◽  
Free Space ◽  
Multiple Input Multiple Output ◽  
Atmospheric Conditions ◽  
Free Space Optical ◽  
Wavelength Division ◽  
Space Optics ◽  
Space Optical Communication ◽  
Input Multiple Output ◽  
And Performance

Abstract Free Space Optical (FSO) communication has evolved as a feasible technique for wireless implementations which offers higher bandwidth capacities over various wavelengths and refers to the transmission of modulated visible beams through atmosphere in order to communicate. Wavelength Division Multiplexing (WDM) is a technology that multiplexes numerous carrier signals onto single fiber using nonidentical wavelengths and enables the efficiency of bandwidth and expanded data rate. Multiple Input Multiple Output (MIMO) is implemented to improve the quality and performance of free space optical communication in various atmospheric conditions. In this paper, a WDM-based FSO communication system is being implemented that benefits from MIMO which receives multiple copies of the signal at receiver that are independent and analyzed for various streams of data in MIMO i.e. 2 × 2, 4 × 4, 8 × 8. Various factors like BER, Quality Factor are analyzed for the WDM-based FSO communication with MIMO using the OptiSystem for various data streams of MIMO under different atmospheric conditions.

scholarly journals Compensated Single Input Multiple Output Flyback Converter

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3009
Author(s):  
Mohammad Tahan ◽  
David O. Bamgboje ◽  
Tingshu Hu
Keyword(s):  
Transient Response ◽  
Current Mode ◽  
Voltage Regulation ◽  
Buck Converter ◽  
Output Channel ◽  
Flyback Converter ◽  
Input Multiple Output ◽  
Voltage Deviation ◽  
Single Input ◽  
The Cross

A new single-input multiple-output (SIMO) converter is proposed in this work by incorporating flyback and buck converters in a master–slave configuration. The objective of this work is to address the cross regulation problem, achieve tight voltage regulation, improve the circuit form factor and attain a fast transient response for a SIMO flyback converter. The flyback converter maintains the output channels within 10% of their rated voltages and the SIMO buck converter is placed in series with the flyback converter such that it compensates for the output voltage deviation. Moreover, a time multiplexing switching scheme decouples output channel to eliminate the cross-regulation problem and remove the need for an additional winding transformer per each output channel. A type II compensator with a peak current mode controller was designed to achieve faster transient response which is critical for the proposed configuration. A thorough steady-state analysis was carried out on a triple output channel topology to obtain the design criteria and component values. MATLAB/Simscape modelling and simulation was used to validate the effectiveness of the proposed converter with the result yielding satisfactory transience even with load disturbance. Additionally, the result of the proposed converter is compared with previously published works.

Robot Assisted Modal Analysis on a Stationary Bladed Wheel

2014 ◽  
Author(s):  
L. Bertini ◽  
B. Monelli ◽  
P. Neri ◽  
C. Santus ◽  
A. Guglielmo
Keyword(s):  
Three Dimensional ◽  
Laser Doppler Vibrometer ◽  
Testing Time ◽  
Real Representation ◽  
The Real ◽  
Complex Formulation ◽  
Frequency Matching ◽  
Input Multiple Output ◽  
Multiple Measurements ◽  
Single Input

This paper shows an automated procedure to experimentally find the eigenmodes of a bladed wheel with highly three-dimensional geometry. The stationary wheel is supported in free-free conditions, neglecting stress-stiffening effects. The single input / multiple output approach was followed. The vibration speed was measured by means of a laser-Doppler vibrometer, and an anthropomorphic robot was used for accurate orientation and positioning of the measuring laser beam, allowing multiple measurements during a limited testing time. The vibration at corresponding points on each blade was measured and the data elaborated in order to find the initial (lower frequency) modes. These modal shapes were then compared to finite element simulations and accurate frequency matching and exact number of nodal diameters obtained. Being the modes cyclically harmonic, the complex formulation could be attractive, being not affected by the angular phase of the mode representation. Nevertheless, stationary modes were experimentally detected, rather than rotating, and then the real representation was necessary. The discrete Fourier transform of the blade displacements easily allowed to find both the angular phase and the correct number of nodal diameters. Successful MAC experimental to analytical comparison was finally obtained with the real representation after introducing the proper angular phase for each mode.

The Ship Track Keeping With Roll Reduction Using a Multiple-States PD Controller on the Rudder Operation

2008 ◽  
Vol 45 (01) ◽  
pp. 21-27
Author(s):  
Ming-Chung Fang ◽  
Jhih-Hong Luo
Keyword(s):  
Numerical Model ◽  
Line Of Sight ◽  
Pd Controller ◽  
Input Multiple Output ◽  
Maneuvering In Waves ◽  
Single Input ◽  
Reduction Function ◽  
Simulation Results ◽  
Guidance Technique ◽  
Present Simulation

The paper presents a nonlinear hydrodynamic numerical model with multiple-states proportional-derivative (PD) controllers for simulating the ship's tracking in random sea. By way of the rudder operation, the track-keeping ability of the PD controller on the ship is examined using the line-of-sight (LOS) guidance technique. Furthermore, the roll-reduction function using the rudder control is also included in the PD controller. From the present simulation results, the single-input multiple-output (SIMO) heading/roll PD controller including LOS technique developed here indeed works, either for the roll reduction or for track keeping while the ship is maneuvering in waves.

Terrestrial Free Space Optic Propagation Analysis Considering Malaysia Weather Condition

2012 ◽  
Author(s):  
Wan Rizal Hazman Wan Ruslan ◽  
Sevia Mahdaliza Idrus ◽  
Arnidza Ramli ◽  
Norhafizah Ramli ◽  
Abu Sahmah Mohd Supa’at ◽  
...  
Keyword(s):  
Bit Error Rate ◽  
Error Rate ◽  
Free Space ◽  
Weather Condition ◽  
Q Factor ◽  
Performance Characterization ◽  
Space Optics ◽  
Terrestrial System ◽  
Data Rates ◽  
Free Space Optic

Pemantulan cahaya matahari oleh cermin atau dikenali sebagai heliograf adalah kaedah awal komunikasi optik wayarles (OWC). Sewajarnya, sistem komunikasi moden mendedahkan kadar data yang tinggi di samping kualiti perkhidmatan yang lebih baik berbanding kaedah terdahulu. Sistem komunikasi optic wayarles mempunyai banyak kebaikan dimana ia adalah penting untuk sistem daratan, sebagai contoh penggunaan Optik Ruang Bebas (FSO) di kawasan luar. Di dalam kertas kerja ini, gambaran dan pencirian prestasi sistem Optik Ruang Bebas seperti pelemahan, kadar bit kesalahan (BER), faktor Q dan jenis pengesan yang berguna untuk pengesanan dalam sistem FSO dibentangkan. Sistem telah direkabentuk dan disimulasi untuk perincian prestasi dengan mengambil kira kawasan Subang. Kata kunci: Pelemahan; kadar bit kesalahan; pengesan foto; faktor Q; sistem daratan The reflection of sunlight by mirrors or known as the heliograph is an early method of optical wireless communication (OWC). Naturally, modern communication system reveals much higher data rates with better quality of service (QoS) compared to those ancient methods. There are many advantages of OWC which are important for a terrestrial system for example the usage of an outdoor free space optics (FSO) system. In this paper, a description and system performance characterization of the FSO such as attenuation, bit error rate (BER), Q factor and the type of detectors that are highly useful for detection in FSO systems are presented. The system are designed and simulated for performance characterization considering Subang terrestrial. Key words: bit error rate; photodetector; Q factor; terrestrial system

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