scholarly journals Performance of Optical Mobile Communications with User Mobility and Multiple Light Sources

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Jian Dang ◽  
Jiajun Gao ◽  
Zaichen Zhang ◽  
Liang Wu ◽  
Bingcheng Zhu ◽  
...  
Keyword(s):  
Mobile Communications ◽  
High Speed ◽  
Signal To Noise Ratio ◽  
High Signal ◽  
Light Sources ◽  
Optical Scheme ◽  
User Mobility ◽  
Optical Wireless ◽  
Free Space Optical ◽  
User Grouping

Optical mobile communication (OMC) is a recently proposed optical wireless communication concept aiming to provide very high-speed data rate optical wireless links for multiple and, in general, distributed mobile users. Previous work analyzed the rate performance of a two-user OMC system without user mobility. This paper extends the rate analysis to multiple users with mobility. The scenario of employing multiple light sources with possible user grouping is also considered. User mobility and multiple light sources lead to new challenges on the system design which are addressed for broadcast downlink communication in this work. Simulations show that user mobility decreases the rate, and the way of how to utilize multiple light sources has great impact on the performance. In particular, simultaneous power division usage of multiple light sources through user grouping and power allocation brings almost no gain as compared with the case of single light source. On the other hand, time division usage of multiple light sources is capable of compensating for the hardware deficiency and thus increasing the rate greatly. It is found that OMC is not only superior to the conventional scheme with nonadjustable channel gains but also outperforms free space optical scheme at high signal-to-noise ratio region.

Non-Resonance Acousto-Optics Signal Analysis from Photonics Microphone Using 1 mW Laser

2016 ◽  
Vol 846 ◽  
pp. 740-747
Author(s):  
Muhammad Adib Akram Mohdami Norashid ◽  
M. Kamil Abd-Rahman
Keyword(s):  
Laser Beam ◽  
Acoustic Waves ◽  
High Speed ◽  
Continuous Wave ◽  
Signal To Noise Ratio ◽  
High Signal ◽  
Free Space Optical ◽  
Signal To Noise ◽  
Optical Signals ◽  
Noise Ratio

This paper presents an acousto-optics analysis on free space optical signals modulated by two distinguishable non-resonant acoustic waves. The acoustic waves were directed at two different directions and locations along a laser beam and created non-interference modulated optical signals. The photonics microphone deploys low-powered eye-safe continuous-wave 633-nm laser; high-speed photodiode and a series of Fourier lenses. Two transducers generating 20 Hz to 20 kHz acoustic waves were directed across the laser beam. The receiving modulated signal was filtered and amplified electronically by two sets of passive bandpass filter separated by a transimpedance amplifier and connected to a computer for analysis. The signal was further digitally filtered and amplified to enhance the signal-to-noise ratio via MATLAB software. These signals were analyzed in time and frequency domains using Fast Fourier Transform (FFT) and Spectrogram. It was found that the recorded signals demonstrated higher signal intensities for lower acoustic frequencies with digital signal-to-noise ratio (SNR) ranging from 10.77 to 71.92 for frequency of 1 kHz to 20 kHz and 20 Hz to 1 kHz respectively. The frequencies of both transducers were simultaneously swept through from 20 Hz and 20 kHz respectively. These scanning frequencies approached one another and crossover with no resonant frequency was observed. This illustrates that it is able to detect multiple acoustic signals for any given frequencies along the laser beam and found its applications in stealth sound detection and long range sound sensor. Though low-powered 1-mW laser was used, a relatively high signal-to-noise ratio with clear-recorded playback was achieved.

scholarly journals High-speed high-resolution laser diode-based photoacoustic microscopy for in vivo microvasculature imaging

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Xiufeng Li ◽  
Victor T C Tsang ◽  
Lei Kang ◽  
Yan Zhang ◽  
Terence T W Wong
Keyword(s):  
High Resolution ◽  
High Speed ◽  
High Performance ◽  
Continuous Wave ◽  
Signal To Noise Ratio ◽  
Cost Effective ◽  
High Signal ◽  
Photoacoustic Microscopy ◽  
Mouse Ear

AbstractLaser diodes (LDs) have been considered as cost-effective and compact excitation sources to overcome the requirement of costly and bulky pulsed laser sources that are commonly used in photoacoustic microscopy (PAM). However, the spatial resolution and/or imaging speed of previously reported LD-based PAM systems have not been optimized simultaneously. In this paper, we developed a high-speed and high-resolution LD-based PAM system using a continuous wave LD, operating at a pulsed mode, with a repetition rate of 30 kHz, as an excitation source. A hybrid scanning mechanism that synchronizes a one-dimensional galvanometer mirror and a two-dimensional motorized stage is applied to achieve a fast imaging capability without signal averaging due to the high signal-to-noise ratio. By optimizing the optical system, a high lateral resolution of 4.8 μm has been achieved. In vivo microvasculature imaging of a mouse ear has been demonstrated to show the high performance of our LD-based PAM system.

scholarly journals Error Performance Estimation of Modulated Retroreflective Transdermal Optical Wireless Links with Diversity under Generalized Pointing Errors

Telecom ◽  
2021 ◽  
Vol 2 (2) ◽  
pp. 167-180
Author(s):  
George K. Varotsos ◽  
Hector E. Nistazakis ◽  
Konstantinos Aidinis ◽  
Fadi Jaber ◽  
Mohd Nasor ◽  
...  
Keyword(s):  
High Speed ◽  
Signal To Noise Ratio ◽  
Spatial Diversity ◽  
Performance Estimation ◽  
Optical Wireless ◽  
Wireless Data ◽  
Error Performance ◽  
Pointing Errors ◽  
Implanted Medical Devices ◽  
Recent Developments

Recent developments in both optical wireless communication (OWC) systems and implanted medical devices (IMDs) have introduced transdermal optical wireless (TOW) technology as a viable candidate for extremely high-speed in-body to out-of-body wireless data transmissions, which are growing in demand for many vital biomedical applications, including telemetry with medical implants, health monitoring, neural recording and prostheses. Nevertheless, this emerging communication modality is primarily hindered by skin-induced attenuation of the propagating signal bit carrier along with its stochastic misalignment-induced fading. Thus, by considering a typical modulated retroreflective (MRR) TOW system with spatial diversity and optimal combining (OC) for signal reception in this work, we focus, for the first time in the MRR TOW literature, on the stochastic nature of generalized pointing errors with non-zero boresight (NZB). Specifically, under these circumstances, novel analytical mathematical expressions were derived for the total average bit error rate (BER) of various system configurations. Their results revealed significant outage performance enhancements when spatial diversity was utilized. Moreover, taking into consideration the total transdermal pathloss along with the effects of stochastic NZB pointing errors, the critical average signal-to-noise ratio (SNR) metric was evaluated for typical power spectral-density values.

Measurement and Analysis of Radial Error Motion of a Miniature Ultra-High-Speed Spindle

2008 ◽  
Vol 381-382 ◽  
pp. 73-76
Author(s):  
Kengo Fujimaki ◽  
Kimiyuki Mitsui
Keyword(s):  
High Speed ◽  
Signal To Noise Ratio ◽  
High Signal ◽  
Signal To Noise ◽  
Measuring Device ◽  
Radial Error ◽  
Optical Measuring ◽  
Ultra High Speed ◽  
Measurement And Analysis ◽  
Error Motion

The optical measuring device developed in this study is based on laser autocollimation and can measure the radial error motions of a miniature ultra-high-speed spindle having a maximum rotational speed of 200 krpm. The maximum response frequency of this optical measuring device is over 500 kHz, while the frequency of the radial error motion at 200 krpm is 3.33 kHz for 1 undulation per revolution (upr), and 333 kHz for 100 upr. In addition, the optical measuring device is capable of a highly detailed analysis of the radial error motion of a miniature ultra-high-speed spindle since it has a high signal-to-noise ratio due to little susceptibility to electrical noises.

Electron Image Analysis

1971 ◽  
Vol 29 ◽  
pp. 80-81
Author(s):  
D. W. Gibbard ◽  
J. A. Crawley ◽  
M. J. Cowham
Keyword(s):  
Image Analysis ◽  
High Resolution ◽  
High Speed ◽  
Signal To Noise Ratio ◽  
High Signal ◽  
Modular Construction ◽  
Wide Range ◽  
Electron Microscopes ◽  
Digital Circuitry ◽  
Accuracy And Repeatability

The history of automatic image analysis is a short one, the techniques being limited until recent years due to the “state of the art” of technology in electronics. A new third generation image analysis machine, the Quantimet 720 was introduced in 1969 designed with a modular construction for application to many fields of interest. It was the first equipment of its type to depart from T.V. standards to scan standards required for optimising the conflicting requirements of high resolution, high speed and high signal to noise ratio. It features high resolution and digital circuitry for accuracy and repeatability and a large and growing range of modules for high computing power. It has also been applied to a wide range of image producing devices including light microscopes, epidiascope (for analysis of photo-micrographs), transmission and scanning electron microscopes.

High-Speed 120 Gbps AMI-WDM-PDM Free Space Optical Transmission System

2019 ◽  
Vol 40 (4) ◽  
pp. 429-433 ◽  
Author(s):  
Kamal Kishore Upadhyay ◽  
Saumya Srivastava ◽  
N. K Shukla ◽  
Sushank Chaudhary
Keyword(s):  
Wavelength Division Multiplexing ◽  
Free Space ◽  
Communication Systems ◽  
High Speed ◽  
Signal To Noise Ratio ◽  
Low Cost ◽  
Free Space Optical ◽  
Wavelength Division ◽  
Received Power ◽  
Polarization Division Multiplexing

Abstract Free space optical (FSO) communication systems are gaining high popularity from the last decade due to its various advantages such as no license spectrum, low-cost implementation etc. In this work, 160 Gbps data is transmitted over 8 km FSO link by adopting alternate mark inversion (AMI), wavelength division multiplexing (WDM) and polarization division multiplexing (PDM) schemes. The results are reported in terms of Q factor, bit error rate, signal to noise ratio, total received power and eye diagrams.

scholarly journals TetrODrive: An open-source microdrive for combined electrophysiology and optophysiology

2020 ◽  
Author(s):  
Marcel Brosch ◽  
Alisa Vlasenko ◽  
Frank W. Ohl ◽  
Michael T. Lippert
Keyword(s):  
Signal To Noise Ratio ◽  
Cell Types ◽  
High Signal ◽  
Light Sources ◽  
3D Printer ◽  
Optogenetic Stimulation ◽  
Open Design ◽  
Reward Prediction ◽  
3D Printed ◽  
The Brain

AbstractObjectiveIn tetrode recordings, the cell types of the recorded units are difficult to determine based on electrophysiological characteristics alone. Optotagging, the use of optogenetic stimulation at the tip of electrodes to elicit spikes from genetically identified cells, is a method to overcome this challenge. However, recording from many different cells requires advancing electrodes and light sources slowly through the brain with a microdrive. Existing designs suffer from a number of drawbacks, such as limited stability and precision, high cost, complex assembly, or excessive size and weight.ApproachWe designed TetrODrive as a microdrive that can be 3D printed on an inexpensive desktop resin printer and has minimal parts, assembly time, and cost. The microdrive can be assembled in 15 minutes and the price for all materials, including the 3D printer, is lower than a single commercial microdrive. To maximize recording stability, we mechanically decoupled the drive mechanism from the electrical and optical connectors.Main resultsThe developed microdrive is small and light enough to be carried effortlessly by a mouse. It provides high signal-to-noise ratio recordings from optotagged units, even across recording sessions. Owing to its moveable optical fiber, our microdrive can also be used for fiber photometry. We evaluated our microdrive by recording single units and calcium signals in the ventral tegmental area (VTA) of mice and confirmed cell identity via optotagging. Thereby we found units not following the classical reward prediction error model.SignificanceTetrODrive is a tiny, lightweight, and affordable microdrive for optophysiology in mice. Its open design, price, and built-in characteristics can significantly expand the use of microdrives in mice.

scholarly journals A PAPR Reduction Technique for Fast Touch Sensors Adopting a Multiple Frequency Driving Method on Large Display Panels

Sensors ◽  
2021 ◽  
Vol 21 (2) ◽  
pp. 429
Author(s):  
Piljoong Kim ◽  
Sanghyun Han ◽  
Yunho Jung ◽  
Seongjoo Lee
Keyword(s):  
High Speed ◽  
Signal To Noise Ratio ◽  
Average Power ◽  
High Signal ◽  
Multiple Frequency ◽  
Signal To Noise ◽  
Large Display ◽  
System Method ◽  
Touch Sensitivity ◽  
Noise Ratio

The multiple frequency driving method (MFDM) capacitive touch system (CTS), which drives transmit (TX) electrodes in parallel, has been developed to improve the touch-sensitivity of large touch screens at high speed. However, when driving multiple TX electrodes at the same time, TX signals are merged through the touch panel, which results in increasing the peak-to-average power ratio (PAPR) of combined signals. Due to the high PAPR, the signal is distorted out of the power amplifier’s linear range, causing a touch malfunction. The MFDM CTS can avoid this problem by reducing the drive voltage or partially driving the TX electrodes in parallel. However, these methods cause a significant performance drop with respect to signal-to-noise ratio (SNR) in the MFDM systems. This paper proposes a stack method which reduces PAPR effectively without the performance degradation of MFDM and achieves real-time touch sensitivity in large display panels. The proposed method allocates a suitable phase for each TX electrode to reduce the peak power of combined signals. Instead of investigating all of the phases for the total number of TX electrodes, the optimal phase is estimated from the highest frequency to the lowest one and fixed one by one, which can reduce the required time to find a suitable phase considerably. As a result, it enables high-speed sensing of multi-touch on a large touch screen and effectively reduces PAPR to secure high signal-to-noise-ratio (SNR). Through experiments, it was verified that the proposed method in this paper has an SNR of 39.36 dB, achieving a gain of 19.35 and 5.98 dB compared to the existing touch system method and the algorithm used in the communication system, respectively.

Next generation optical wireless communication: a comprehensive review

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Deepak Garg ◽  
Abhimanyu Nain
Keyword(s):  
Wireless Communication ◽  
Optical Networks ◽  
Signal To Noise Ratio ◽  
Network Capacity ◽  
Next Generation Networks ◽  
High Signal ◽  
Large Network ◽  
Optical Wireless Communication ◽  
Optical Wireless ◽  
Next Generation

Abstract Next generation wireless networks are the need of the hour with reliable, high bandwidth, low Bit Error Rate (BER), high Signal to Noise Ratio (SNR), large network capacity, etc. for a paradigm shift to all optical networks from the prevailing conventional electro optic network due to the various benefits of optical links such as enormous bandwidth and extremely low losses. This paper presents a primitive overview of the foregoing technologies and then move on to encapsulating the contemporary techniques to enhance the system performance. For this, preceding limitation and their respective improvement measures from literature of fiber communication and its integration with the next generation networks mainly based upon Radio over Fiber (RoF), Fiber to the Home (FTTH) and Free Space Optics (FSO) are discussed. The advancement in the domain of optical wireless communication utilizing various methodologies is summarized. Finally, we conclude by incorporating various cost reduction methodologies developed which may further be explored to make next generation networks more promising.

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