Informatics Publishing Limited

J. Ilouno ¹, B. J. Kwaha ², A. M. Batu ³

Affiliations
1 Department of Remedial Studies, University of Jos, Jos, NG
2 Dept. of Physics, University of Jos, Jos., NG
3 Department of Science and Technology, Kaduna Polytechnic, NG

Abstract

In this paper, channel attenuation (link loss) and fiber loss budget for different types and sizes of optic fibres in selected applications in RF communications were measured and computed using relevant equations to ascertain accuracy of measurements and also for comparison sake. The results obtained agree with each other. The minor differences in values noticed in comparing the calculated and manufacturer's values make only a negligible impact in practical RF communication. In line with theory, the computed values show that channel attenuation increases as distance increases. Multi-mode fibers with smaller core diameters offer less attenuation. Multi-mode fiber operating in 1300 nm wavelength for application 100G-M-SN-I (500 m supportable distance) gives 2.95 dB compared to 850 nm fiber with 3.90 dB of the same size. Single-mode 1550 nm fibers offer less attenuation compared to 1310 nm fibers. Furthermore, the measured values of attenuation of different optic fiber colours at Zain, Abuja upholds the manufacturers' assertion that turquoise, red, brown, pink, and green fiber coatings are good for indoor connectivity while white, black, yellow, blue and orange are recommended for outdoor transmissions.

Keywords

Fibre Optics, RF Applications, Channel Attenuation

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B. J. Kwaha ¹, E. A. Kolawole ¹, A. M. Batu ²

Affiliations
1 Dept. of Physics, University of Jos, Jos., NG
2 Dept. of Science and Technology, Kaduna Polytechnic, NG

Abstract

This research compares two IIR digital filter design and implementation methods- viz MATLAB direct method and Bilinear transformation method. Programs to design and implement Butterworth IIR lowpass digital filters were developed and executed using both methods. In the design, at F_pass of 1Hz, F_stop of 2.414 Hz, using MATLAB method the 3 dB frequency is at 1.605 Hz while using the Bilinear transformation method the 3 dB frequency is at 1.395 Hz. At F_pass of 0.7839Hz, F_stop of 2.007 Hz, using MATLAB method the 3 dB frequency is at 1.181 Hz while using the Bilinear method the 3 dB frequency is at 1.001 Hz. From the design it was observed that the Butterworth filter has maximally flat passband in its frequency response and a poor roll-off at its bandstop which is in line with predicted theory. The Butterworth filters designed using Bilinear transformation were more stable with a monotonically decreasing gain response due to its poor roll-off which may be associated to discrete component performance. The magnitude of the passband decreases as the order of the filter increases. The designs also show that higher order filters have sharper skirts and may be used in phase modulated wave (PMW) applications.

Keywords

Matlab, Bilinear Transformation Methods, Filter Design

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