scholarly journals Testing Time and Frequency Fiber-Optic Link Transfer by Hardware Emulation of Acoustic-Band Optical Noise

2016 ◽  
Vol 23 (2) ◽  
pp. 309-316
Author(s):  
Marcin Lipiński ◽  
Przemysław Krehlik ◽  
Łukasz Śliwczyński ◽  
Łukasz Buczek ◽  
Jacek Kołodziej
Keyword(s):  
Fiber Optic ◽  
Data Transfer ◽  
Acoustic Noise ◽  
Mechanical Vibration ◽  
Low Frequency ◽  
Propagation Delay ◽  
Optical Signal ◽  
Testing Time ◽  
Optical Noise ◽  
Signal Phase

Abstract The low-frequency optical-signal phase noise induced by mechanical vibration of the base occurs in field-deployed fibers. Typical telecommunication data transfer is insensitive to this type of noise but the phenomenon may influence links dedicated to precise Time and Frequency (T&F) fiber-optic transfer that exploit the idea of stabilization of phase or propagation delay of the link. To measure effectiveness of suppression of acoustic noise in such a link, a dedicated measurement setup is necessary. The setup should enable to introduce a low-frequency phase corruption to the optical signal in a controllable way. In the paper, a concept of a setup in which the mechanically induced acoustic-band optical signal phase corruption is described and its own features and measured parameters are presented. Next, the experimental measurement results of the T&F transfer TFTS-2 system’s immunity as a function of the fibre-optic length vs. the acoustic-band noise are presented. Then, the dependency of the system immunity on the location of a noise source along the link is also pointed out.

scholarly journals Identification and Removal of Non-acoustic Noise in Towed Array Sonar Using F-Κ Transform for Enhanced Torpedo Detection

2020 ◽  
Vol 14 ◽  
Keyword(s):  
Vibration Isolation ◽  
Acoustic Noise ◽  
Detection System ◽  
Mechanical Vibration ◽  
Low Frequency ◽  
Acoustic Energy ◽  
Noise Sources ◽  
Towed Array ◽  
Spatio Temporal ◽  
Towed Arrays

Low frequency passive towed array sonar is an essential component in a torpedo detection system for surface ships. Compact towed arrays are used for torpedo detection and they will be towed at higher towing speeds compared to conventional towed array sonars used for surveillance. Presence of non-acoustic noise in towed array sensors at higher towing speeds degrades torpedo detection capability at lower frequencies. High wavenumber mechanical vibrations are induced in the array by vortex shedding associated with hydrodynamic flow over the array body and cable scope. These vibrations are known to couple into the hydrophone array as nonacoustic noise sources and can impair acoustic detection performance, particularly in the forward end fire direction. Lengthy mechanical vibration isolation modules can isolate vibration induced noise in towed arrays, but this is not recommended in a towed array which is towed at high speeds as it will increase the drag and system complexity. An algorithm for decomposing acoustic and non-acoustic components of signals received at sensor level using well known frequency-wavenumber transform (F-K transform) is presented here. Frequency-wavenumber diagrams can be used for differentiating between acoustic and non-acoustic signals. An area of V shape is identified within the F-K spectrum where acoustic energy is confined. Energy outside this V will highlight non-acoustic energy. Enhanced simultaneous spatio-temporal and spatio-amplitude detection is possible with this algorithm. Performance of this algorithm is validated through simulation and experimental data.

scholarly journals Thermal effect on the optical signal of fiber optics networks

2021 ◽  
Author(s):  
Abdulrazak A. Mohammed ◽  
Ghassan A. QasMarrogy
Keyword(s):  
Fiber Optics ◽  
Fiber Optic ◽  
Data Transfer ◽  
Optical Signal ◽  
Effect Of Temperature ◽  
Optical Components ◽  
Fiber Optic Network ◽  
Modern System ◽  
Optic Network ◽  
Main Material

Abstract Fiber Optic Network is an advanced and modern system technology, which is used in sending pulses of laser light inside a glass of fiber over long distances, widely used in every environment with various sorts of applications in a different field. It is well-known that the main material of fiber optics is glass, therefore it is typical that the temperature can affect the glass during the thermal expansion. This effect will be applied to the properties of the optical components such as refractive index, radius curvature of the fiber optics layers, and also there is an effect on the data transfer through the fiber optics network units. In this paper, the effect of temperature degree on the optical signal and the functions of the fiber optic network will be simulated, measured, and analyzed. The result will be discussed and the conclusion will show the serious points of thermal effects on the optical signal of a fiber-optic network.

scholarly journals PROBLEMS OF THE EFFICIENCY OF FIBER OPTIC COMMUNICATION LINES

2019 ◽  
Vol 2019 (2) ◽  
pp. 161-168
Author(s):  
K Dadamatova ◽  
◽  
A Nazarov ◽  
N Gerasimenko
Keyword(s):  
Fiber Optic ◽  
Low Cost ◽  
Optical Signal ◽  
Optical Noise ◽  
Advantages And Disadvantages ◽  
Technical Function ◽  
Fiber Optic Communication ◽  
Optic Communication ◽  
The Cost ◽  
Communication Lines

The article presents the results of solving the problem of attenuation of an optical signal in fiber-optic communication lines. Widely used modern technical solutions of intermediate amplification-regenerative nodes of fiber-optic communication lines are described. The advantages and disadvantages of existing intermediate fiber optic amplifiers are presented. The benefits of optoelectronic signal regenerators include a full restoration of the original properties of the optical signal. The optoelectronic regenerator allows to limiting the amount of internal and external optical noise by acceptable values, but increases and increases the cost of building optical fiber connections.Optical signal amplifiers are also used to increase the range of fiberoptic communication lines. The main advantage of intermediate fiber optic amplifiers is their relatively simple design and, consequently, low cost, as well as high cost of losses and power output.The technical function of the developed fiber optic amplifier is to create a signal and power amplifier that is evenly distributed inside the fiber located in the region of the fiber containing the fluorescent additive.The characteristics, functional and structural diagrams of an optical repeater with erbium amplifiersare shown in detail. The design features of the construction and the principle of operation of the erbium amplifier are described.

scholarly journals The Relationship between Vibratory Sensation and Body Surface Vibration Induced by Low-Frequency Noise

2002 ◽  
Vol 21 (2) ◽  
pp. 87-100 ◽  
Author(s):  
Yukio Takahashi ◽  
Kazuo Kanada ◽  
Yoshiharu Yonekawa
Keyword(s):  
Body Surface ◽  
Mechanical Vibration ◽  
Low Frequency ◽  
The Body ◽  
Frequency Noise ◽  
Low Frequency Noise ◽  
Vibration Acceleration ◽  
Surface Vibration ◽  
Human Body Surface ◽  
The Relationship

Human body surface vibration induced by low-frequency noise was measured at the forehead, the chest and the abdomen. At the same time, subjects rated their vibratory sensation at each of these locations. The relationship between the measured vibration on the body surface and the rated vibratory sensation was examined, revealing that the vibratory sensations perceived in the chest and abdomen correlated closely with the vibration acceleration levels of the body surface vibration. This suggested that a person exposed to low-frequency noise perceives vibration at the chest or abdomen by sensing the mechanical vibration that the noise induces in the body. At the head, on the other hand, it was found that the vibratory sensation correlated comparably with the vibration acceleration level of the body surface vibration and the sound pressure level of the noise stimulus. This finding suggested that the mechanism of perception of vibration in the head is different from that of the perception of vibratory sensation in the chest and the abdomen.

Aerodynamic Drag Measurement in a High-Enthalpy Shock Tunnel

2018 ◽  
Author(s):  
Yunpeng Wang ◽  
Zonglin Jiang ◽  
Honghui Teng
Keyword(s):  
Natural Frequencies ◽  
Aerodynamic Drag ◽  
Aerodynamic Force ◽  
Mechanical Vibration ◽  
Low Frequency ◽  
Shock Tunnel ◽  
Test Time ◽  
Test Duration ◽  
Flow State ◽  
High Enthalpy

Shock tunnels create very high temperature and pressure in the nozzle plenum and flight velocities up to Mach 20 can be simulated for aerodynamic testing of chemically reacting flows. However, this application is limited due to milliseconds of its test duration (generally 500 μs–20 ms). For the force test in the conventional hypersonic shock tunnel, because of the instantaneous flowfield and the short test time [1–4], the mechanical vibration of the model-balance-support (MBS) system occurs and cannot be damped during a shock tunnel run. The inertial forces lead to low frequency vibrations of the model and its motion cannot be addressed through digital filtering. This implies restriction on the model’s size and mass as its natural frequencies are inversely proportional the length scale of the model. As to the MBS system, sometimes, the lowest natural frequency of 1 kHz is required for the test time of typically 5 ms in order to get better measurement results [2]. The higher the natural frequencies, the better the justification for the neglected acceleration compensation. However, that is very harsh conditions to design a high-stiffness MBS structure, particularly a drag balance. Therefore, it is very hard to carried out the aerodynamic force test using traditional wind tunnel balances in the shock tunnel, though its test flow state with the high-enthalpy is closer to the real flight condition.

Design and Simulation of a PC to PC Communication Network via Fiber Optic Cable

2013 ◽  
Vol 824 ◽  
pp. 206-214
Author(s):  
Babatunde A. Adegboye ◽  
B.B. Bello ◽  
K.R. Ekundayo ◽  
Juliet N. Adegboye
Keyword(s):  
Communication Network ◽  
Fiber Optic ◽  
Data Transfer ◽  
The Internet ◽  
Serial Port ◽  
Fiber Optic Cable ◽  
Optical Transmitter ◽  
Wireless Medium ◽  
Fiber Optic Communication ◽  
Optic Communication

This paper deals with data transfer from one computer to another. The serial ports of the computer are used. MAX 232 is used to convert RS 232 logic to TTL logic and then an optical transmitter circuit is used to transmit data via fiber optic cable. The optical transmitter circuit has an LED which is matched with the cable. At the receiver an optical receiver circuit is used which receives data using a photo diode and a MAX 232 again to convert TTL logic to RS 232 for the serial port at the receiving end computer. The desired baud rate can be set. Although the internet can be used, but due to its time consuming nature, one can implement data transfer using wireless medium, though at a relatively high cost. The need, therefore, is felt for fiber optic communication which is cheaper and more suitable for the task. It is cheaper than wireless medium and is prone to lesser loss as compared to wireless medium.

scholarly journals Pendulum-Type Hetero-Core Fiber Optic Accelerometer for Low-Frequency Vibration Monitoring

Sensors ◽  
2018 ◽  
Vol 18 (8) ◽  
pp. 2528 ◽  
Author(s):  
Hiroshi Yamazaki ◽  
Ichiro Kurose ◽  
Michiko Nishiyama ◽  
Kazuhiro Watanabe
Keyword(s):  
Fiber Optics ◽  
Electromagnetic Interference ◽  
Large Scale ◽  
Fiber Optic ◽  
Low Frequency ◽  
Fiber Optic Sensor ◽  
Vibration Monitoring ◽  
Vibration Measurement ◽  
Displacement Sensor ◽  
Core Fiber

In this paper, a novel pendulum-type accelerometer based on hetero-core fiber optics has been proposed for structural health monitoring targeting large-scale civil infrastructures. Vibration measurement is a non-destructive method for diagnosing the failure of structures by assessing natural frequencies and other vibration patterns. The hetero-core fiber optic sensor utilized in the proposed accelerometer can serve as a displacement sensor with robustness to temperature changes, in addition to immunity to electromagnetic interference and chemical corrosions. Thus, the hetero-core sensor inside the accelerometer measures applied acceleration by detecting the rotation of an internal pendulum. A series of experiments showed that the hetero-core fiber sensor linearly responded to the rotation angle of the pendulum ranging within (−6°, 4°), and furthermore the proposed accelerometer could reproduce the waveform of input vibration in a frequency band of several Hz order.

scholarly journals Investigation of sub-carrier multiplexed fiber optic link supporting WLAN and WCDMA

2021 ◽  
Author(s):  
Roland M. C. Yuen
Keyword(s):  
Access Control ◽  
Medium Access Control ◽  
Mobile Communication ◽  
Fiber Optic ◽  
Multipath Fading ◽  
Numerical Results ◽  
Optical Noise ◽  
Medium Access ◽  
Air Interface ◽  
Nonlinear Distortions

In this thesis, an optical fiber based radio access architecture that simultaneously provides services of the wireless local area network (WLAN) and the third generation (3G) mobile communication system is investigated. The sub-carrier multiplexed (SCM) technique of the fiber optic system is considered. The SCM architecture does not require frequency conversion and plays an important role enabling the WLAN to complement the cellular mobile communication systems so that the user can have both services as needed. In the SCM architecture, the two mediums that signals propagate are the air interface and the radio over fiber (ROF) link. In the air interface, the signal experience path loss and multipath fading that have effect on the system performance. The ROF link introduces nonlinear distortions and optical noise. The uplink and downlink analysis are performed in this thesis considering all the impairments from the air interface and the ROF link. Thereafter, numerical results are generated for both the uplink and downlink to illustrate the performance of the SCM architecture. The analysis identifies the interdependent relationship of the WLAN and the WCDMA system. The numerical results graphically illustrate such interdependent relationship. In the downlink, a 5 km ROF link operating at optimal power can support a WCDMA system with 1 km radius of coverage that has 26 dB of signal to distortion and noise ratio (SDNR); and a WLAN system with 400 m radius of coverage that has 27 dB of SDNR. The throughput of IEEE 802.11 WLAN depends on the medium access control. Hence, the medium access control is investigated and the throughput expression is modified to adapt to the SCM architecture where signals travel extra distance in a fiber.

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