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.

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 A Novel Technique for Achieving the Approximated ISI at the Receiver for a 16QAM Signal Sent via a FIR Channel Based Only on the Received Information and Statistical Techniques

Entropy ◽  
2020 ◽  
Vol 22 (6) ◽  
pp. 708
Author(s):  
Hadar Goldberg ◽  
Monika Pinchas
Keyword(s):  
Edgeworth Expansion ◽  
Finite Impulse Response ◽  
Signal To Noise Ratio ◽  
Signal Transmission ◽  
Entropy Density ◽  
Approximation Technique ◽  
Novel Technique ◽  
Input Multiple Output ◽  
Source Signal ◽  
Single Input

A single-input-multiple-output (SIMO) channel is obtained from the use of an array of antennas in the receiver where the same information is transmitted through different sub-channels, and all received sequences are distinctly distorted versions of the same message. The inter-symbol-interference (ISI) level from each sub-channel is presently unknown to the receiver. Thus, even when one or more sub-channels cause heavy ISI, all the information from all the sub-channels was still considered in the receiver. Obviously, if we know the approximated ISI of each sub-channel, we will use in the receiver only those sub-channels with the lowest ISI level to get improved system performance. In this paper, we present a systematic way for obtaining the approximated ISI from each sub-channel modelled as a finite-impulse-response (FIR) channel with real-valued coefficients for a 16QAM (16 quadrature amplitude modulation) source signal transmission. The approximated ISI is based on the maximum entropy density approximation technique, on the Edgeworth expansion up to order six, on the Laplace integral method and on the generalized Gaussian distribution (GGD). Although the approximated ISI was derived for the noiseless case, it was successfully tested for signal to noise ratio (SNR) down to 20 dB.

scholarly journals Performance of channels coding and space-time trellis codes on fading channel for multiple-input multiple-output free-space optical communication systems

2021 ◽  
Author(s):  
Ebrahim E. Elsayed
Keyword(s):  
Free Space ◽  
Communication Systems ◽  
Smart Antenna ◽  
Signal To Noise Ratio ◽  
Multiple Input Multiple Output ◽  
Space Time ◽  
Free Space Optical ◽  
Trellis Codes ◽  
Multiple Input ◽  
Input Multiple Output

Abstract In this paper, we review and analyze the space-time trellis codes with and without ideal beamforming. Space-time trellis code with ideal beamforming at transmitter termed as weighted space. Smart antenna technology provides a wide variety of options, ranging from single-input multiple-output architectures that collect more energy to improve the signal-to-noise ratio at the receiver, to multiple-input multiple-output (MIMO) architectures that open up multiple data pipes over a link. Atmospheric turbulence can cause significant performance degradation in free-space optical (FSO) communication systems. An efficient solution could be to exploit the temporal diversity to improve the performance of the FSO link.

scholarly journals Remote whispering metamaterial for non-radiative transceiving of ultra-weak sound

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Jin Zhang ◽  
Wei Rui ◽  
Chengrong Ma ◽  
Ying Cheng ◽  
Xiaojun Liu ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Detection Limit ◽  
Free Space ◽  
Signal To Noise Ratio ◽  
Resonance Energy Transfer ◽  
Information Leakage ◽  
Resonance Energy ◽  
Acoustic Analogy ◽  
Signal To Noise ◽  
Airborne Sound

AbstractTransceiving ultra-weak sound typically relies on signal pre-amplification at the transmitting end via active electro-acoustic devices, which inherently perturbs the environment in the form of noise that inevitably leads to information leakage. Here we demonstrate a passive remote-whispering metamaterial (RWM) enabling weak airborne sound at audible frequencies to reach unprecedented signal enhancement without altering the detected ambient soundscape, which is based on the extraordinary scattering properties of a metamaterial formed by a pair of self-resonating subwavelength Mie meta-cavities, constituting the acoustic analogy of Förster resonance energy transfer. We demonstrate efficient non-radiative sound transfer over distances hundreds times longer than the radius of the meta-cavities, which enables the RWM to recover weak sound signals completely overwhelmed by strong noise with enhanced signal-to-noise ratio from −3 dB below the detection limit of 0 dB in free space to 17.7 dB.

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.

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