American Journal of Electrical and Electronic Engineering

It is shown that the whole practice of using Ohm’s law in the theory of electrical circuits is actually a theoretical and experimental evidence for physical reality of imaginary numbers. Therefore, the current interpretation of the special theory of relativity, which denies physical reality of imaginary numbers, requires appropriate adjustment. The adjusted version of the special theory of relativity can explain the phenomena of dark matter and dark energy. Other exact sciences also require adjustment with regard to the principle of physical reality of imaginary numbers.

American Journal of Electrical and Electronic Engineering. 2015, 3(5), 124-129. DOI: 10.12691/ajeee-3-5-3
Pub. Date: December 01, 2015

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Implementation and Performance Evaluation of OFDM System in Diverse Transmission Channel Using Simulink

by Arun Agarwal and Kabita Agarwal

Original Research

Orthogonal Frequency Division Multiplexing (OFDM) has become a popular modulation method in high data rate wireless communications. It is a key modulation scheme that is especially suited for high-data-rate transmission in delay-dispersive environments because of its robustness to Inter-Symbol Interference (ISI) and multipath fading environment. It converts a high-rate data stream into a number of low-rate streams that are transmitted over parallel, narrowband channels which needs little or no equalization. OFDM also provides efficient spectrum utilization by use of single frequency networks (SFNs). Recently, OFDM has become the standard for physical layer implementation of various digital audio and video wireless communications such as DAB/DVB, wireless local access networks (WLANs) and wireless metropolitan area networks (WMANs). Moreover OFDM is a potential candidate for fourth-generation (4G) mobile wireless systems and beyond. In this paper, through Simulink implementation, we present a bit error rate (BER) performance analysis of OFDM system in diverse transmission channels. The results show that OFDM is well suited for high speed data transmission in mobile environment and channel coding combined with interleaving is mandatory for any wireless high speed transmission.

American Journal of Electrical and Electronic Engineering. 2015, 3(5), 117-123. DOI: 10.12691/ajeee-3-5-2
Pub. Date: November 30, 2015

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A Digital Filter for Electrical Drive with Elastic Shaft

by Jumber Dochviri, Oleg Khachapuridze and Nana Beradze

Original Research

In the paper analytically is constructed digital filter for DC-electrical drive with elastic junctions. It could be realized with two discrete integrators and five operational amplifiers. The filter would be insert sequentially on the output of the speed’s regulator. As results transient processes similar to transients of dc-electric drive with rigid mechanical shaft are obtained.

American Journal of Electrical and Electronic Engineering. 2015, 3(5), 112-116. DOI: 10.12691/ajeee-3-5-1
Pub. Date: November 03, 2015

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