Investigation of EDFA positioning impact on the quality of the amplified signal in DWDM transmission systems

Author(s):  
Julija Putrina ◽  
Sergejs Olonkins ◽  
Vjaceslavs Bobrovs
Keyword(s):  
Author(s):  
A. Machizawa ◽  
K. Sugiura ◽  
T. Komine ◽  
H. Okazawa ◽  
S.-I. Nakagawa ◽  
...  

Author(s):  
Volodymyr Kotukh ◽  
Natalia Kaptsova ◽  
Dmitry Donskoy ◽  
Kateryna Paleyeva

Modern gas transmission systems are power facilities based on a main pipeline, which is a continuous pipe, along which devices are placed that provide gas pumping at predetermined parameters. Unlike other linear structures, such as roads, railways, the main pipeline throughout the entire period of operation is in a complex stress state under the influence of the internal pressure of the pumped product and functions as a pressure vessel. The operational reliability, durability and environmental safety of gas transmission systems are ensured by various control devices and pipe fittings. The article discusses issues related to predicting the operation of pipe fittings during the operation of the gas transmission system, while ensuring the required reliability, durability and environmental safety. An analysis of the phenomena of technical heredity is given, with the help of which it is possible to determine the causes of deviations in the output parameters of pipe fittings in the process of their manufacture or repair. It has been proved that the main feature of technological heredity is the transfer of a certain technological property from the previous technological operation to subsequent ones, characterized by the transfer coefficient of technological heredity. An indispensable condition for the monotonicity of changes in the transmission coefficient of technological heredity in order to ensure the required quality of manufacture or repair of pipe fittings is revealed. The economic principle of predicting the quality of manufacturing or repair of products is proposed for use, a relationship is found between the initial and output technological properties of pipe fittings, a route is chosen to achieve the required quality of its manufacture or repair, including procurement and finishing technological operations.


2019 ◽  
Vol 56 (2) ◽  
pp. 42-53
Author(s):  
J. Putrina ◽  
S. Olonkins ◽  
V. Bobrovs ◽  
J. Porins

Abstract The article investigates dependence of EDFA performance on its operating conditions. First of all, the impact of changes in channel spacing on the quality of the amplifier signal and on the desired EDFA configuration is observed – three different values of channel spacing are considered – 37.5 GHz, 50 GHz and 100 GHz. Afterwards, the impact of EDFA positioning on the quality of the amplified signal and the desired configuration is assessed. Three different EDFA positioning scenarios are considered – when the EDFA is used as a power booster, as an in-line amplifier and as a preamplifier. In all cases, such configuration of the EDFA is found that can ensure bit-error ratio (BER) values below 1·10−9 in all channels of the system. To assess the performance of the amplifiers, power penalty values are obtained in respect to identical transmission systems but without amplification.


2021 ◽  
Vol 7 (1) ◽  
pp. 33-38
Author(s):  
Augustin Vyukusenge ◽  

System distortions due to chromatic dispersion (CD), polarization mode dispersion (PMD), laser phase noise and fiber nonlinearities have a significant impact on the performance of high-speed fiber optic networks. In connection with the need to improve the quality of information transmission in high-speed fiber-optic communication systems, coherent detection with a digital signal processing unit is of particular interest. The main goal of the DSP block is to reduce the impact of linear and nonlinear effects that degrade the quality of information transfer. In this direction, the use of adaptive filters with adaptation algorithms for filter coefficients plays an important role. The Constant Modulus Algorithm (CMA) and the Least Mean Square (LMS) method used to compensate for dispersion distortions are presented. The load on transport networks based on fiber-optic transmission systems is increasing at an accelerating rate. This paper discusses the possibility and limitations of increasing the throughput of fiber-optic transmission systems by reducing the distance between carriers. A comparison is made between fixed and flexible grids in terms of the spectral bandwidth efficiency. It is concluded that the use of flexible mesh technology is promising when switching to channel speeds above 100 Gbit/s.


2018 ◽  
Vol 11 (1) ◽  
Author(s):  
F. Javier Andrés ◽  
Antonio Pérez-González ◽  
Carlos Rubert ◽  
José Fuentes ◽  
Bruno Sospedra

The popularization of fused deposition modeling (FDM) technology and open-source microcontrollers has permitted the explosion of electric hand prostheses that can be designed, shared, built, and operated at a low cost, under the Do It Yourself premise. Patients with limb reductions at the transcarpal or transradial level are best candidates to benefit from them. They manage the gross location with the remaining limb, while the built-in motors offer the possibility of controlling each finger independently. The number of mobile joints along the finger and the type of transmission can determine the quality of the grasp. Moreover, there is a need of objective procedures to assess the functionality of complete prototypes at reasonable effort. This work makes a critical review of the different transmission systems that can be found in most low-cost finger designs: linkage and tendon mechanisms. Mechanical performance has been analyzed using a standardized model of the index finger. Furthermore, robotic grasp quality metrics (GQM) have been used to evaluate by simulation the functionality of complete devices. Neither finger transmission design appeared clearly advantageous in the range of flexion studied. The evaluation of the complete devices gave slightly better quality grades for the linkage-driven model. Instead, tendon-driven model achieved a greater quantity of successful grasps. In the current state of art, some other aspects may have led to a dominant situation of the tendon-driven hands: fewer number of parts to be printed, easier assembly for a nonexpert user, advantageous in pursuit of lightweight devices.


Author(s):  
K. T. Tokuyasu

During the past investigations of immunoferritin localization of intracellular antigens in ultrathin frozen sections, we found that the degree of negative staining required to delineate u1trastructural details was often too dense for the recognition of ferritin particles. The quality of positive staining of ultrathin frozen sections, on the other hand, has generally been far inferior to that attainable in conventional plastic embedded sections, particularly in the definition of membranes. As we discussed before, a main cause of this difficulty seemed to be the vulnerability of frozen sections to the damaging effects of air-water surface tension at the time of drying of the sections.Indeed, we found that the quality of positive staining is greatly improved when positively stained frozen sections are protected against the effects of surface tension by embedding them in thin layers of mechanically stable materials at the time of drying (unpublished).


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