iosr-JEEE   Volume-15 ~ Issue-5 ~ Sep. – Oct. 2020

Abstract: In this paper, we have simulated Coherent Detection Optical Orthogonal Frequency Division Multiplexing (CO-OFDM) system with different type of modulation techniques such as Quadrature Amplitude Modulation (QAM) and Phase Shift Keying (PSK). 64-QAM and 16-PSK modulation with same number of subcarriers were applied to CO-OFDM system to achieve the best Bit Error Rate (BER) performance. According to the best BER, the downstream data rate was chosen to be 60 Gbps and transmission distance was changed from 50 to 350 km. According to the simulation results by using Optisystem software, CO-OFDM system with 16 PSK and 128 subcarriers achieved the best BER performance for long propagation.

Keywords: Orthogonal Frequency Division Multiplexing (OFDM), Phase Shift Keying (PSK), Quadrature Amplitude Modulation (QAM), CoherentDetection OFDM (CO-OFDM)

[1]. J. Armstrong, "OFDM for Optical Communications," IEEE J. Of Lightwave Technology," J. Lightwave Technol., 27, 189-204 (2009)
[2]. T. Nguyen, S. Mhatli, E. Giacoumidis, L. Van Compernolle, M. Wuilpart and P. Mégret, "Fiber Nonlinearity Equalizer Based on Support Vector Classification for Coherent Optical OFDM, " IEEE Photonics J., 8, 7802009 (2016)
[3]. F. El-Nahal, "Coherent 16 Quadrature Amplitude Modulation (16QAM) Optical Communication Systems," Photonics Lett. Pol., 9, 57- 59 (2018)
[4]. S. Jansen I. Morita, T. Schenk, N. Takeda, and H. Tanaka, "Coherent Optical 25.8-Gb/s OFDM Transmission Over 4160-km SSMF, " J. Lightwave Technol., 1 - 10 (2007)
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Abstract: In the context of high-speed circuits, the layout analysis of the Printed Circuit Boards (PCB) is always critical and necessary. Due to the high costs of rework when the problems are detected in the clients and due high costs of tools, such as Vector Network Analyzer, for analysis behavior of circuits, using simulation tools is the best way to detect problems in high-speed designs.This work proposes a method to identify phenomena, such as ripple, crosstalk, insertion losses and return losses, that degrade the integrity of signals in transmission lines, evaluating, through simulations, circuits in the frequency domain (S-Parameters). The proposed solutions, changes were made in the printed circuit board design itself, and a simulation of noises from industrial processes was also used to correct problems related in PCB traces, more specific back drilling.

Key Words: High speed signals, Insertion loss,Mixed Mode S-Parameters, Return loss and Signal integrity.

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[4]. Samtec, Inc. Interconnect Signal Integrity Handbook. Company Education, 2007.
[5]. Carrio, Fernando. A capacitor selector tool for on-board PDN designs in multigigabit applications. IEEE International Symposium on Electromagnetic Compatibility. Long Beach, p. 367-372, 2011.

Abstract: For power generation we need a new renewable energy resource which must be constant and never-ending, so gravitational energy is the aid. It is a limitless form of energy present all over the earth. Hence, creating an apparatus which generates electric power from the gravitational forces is sole concept of this project. This gravitational force can be utilized in the form of energy resource and can be converted in different forms of energy. By this simplified arrangement which is eco-friendly and has very less maintenance cost we can harness this limitless form of energy by converting it into electrical form only using a compound gear mechanism and a weight.

Key Words: Gravity, Gears, Weight, Power Generation

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