Active Inductor and Capacitor for DCS receiver band (1.71GHz – 1.785GHz) using multi-MESFET Negative Resistance Circuit

Traditional spiral inductors are usually large, bulky, and difficult to model, hence active inductors look very attractive particularly because of their tuning capability. The basic idea of this design is to realize an active inductor and capacitor that could be used to substitute the spiral inductors and lumped capacitors in Monolithic Microwave Integrated Circuit (MMIC) active filters. The resulting negative resistance serves to compensate the pass-band insertion loss. The benefits of reduced cost, small size and weight justify the effort to develop fully integrated Radio Frequency (RF) and Microwave systems using MMIC technology. In line with this interest, this work will lay a key foundation on which the step toward full integration can be made. For proof of concept, a 5GHz active capacitor using single MESFET negative resistance was designed, simulated and fabricated by GEC F20 Foundry. The test and measurement was done using HP8510 Network Analyzer. The simulated and measured results compared well. Following on this concept, an active inductor for dcs receiver band (1.71GHz – 1.785GHz) using multi-MESFET negative resistance circuit was designed and simulated. The results obtained show constant inductor and negative resistance values within the desired frequency ban

Applications and Benefits of Nonlinearities in Optical Fibres in Wavelength Division Multiplexed Systems

Optical nonlinearities play a major role in optical fibre with respect to transmission capacity and performance of the system. This degrades the system performance, especially in wavelength division multiplexing (WDM) systems, where several channels co-exist in the same fibre and propagating simultaneously, resulting in high optical intensities. They can result in pulse distortion referred to as self phase modulation (SPM), cross phase modulation (XPM), crosstalk between channels, and four wave mixing (FWM). However, these non-linearities also have many useful applications, especially for the implementation of all-optical functionalities in optical networks. In this paper, we briefly review the different kinds of optical nonlinearities encountered in fibres, identify the essential materials and fibre parameters that determine them. The paper simulates two channel WDM optical communication systems in single mode fibre over long haul of 100 km to investigate the effect of SPM, XPM and FWM. Their thresholds, managements and applications are also discussed; and comparative study of these effects is presented

ECG Biosignal: Vital for Detecting Cardiovascular Diseases

The World Health Organization estimated that 31% mortality rate in the World is due to cardiovascular diseases such as heart arrhythmia and heart failure. Therefore there is a need to innovate methods to accurately detect those diseases from Electrocardiography (ECG) biosignals, and develop algorithms to analyze the signals for precise diagnosis by physicians. This paper is a study of ECG biosignals, detection of heart arrhythmia from characteristic pattern of the ECG waveform, and signal-processing techniques for analysis of the biosignals. Also in this study, ECG results of a male volunteer are shown to emphasize the importance of exercises as one of the factors for preventing cardiovascular diseases

Optic Fibericity - The New Era Lighting

Bringing sunlight inside buildings to decrease the electricity needed for lighting, to provide natural light, and to decrease the energy needed for cooling has been a major technology research interest referred to as daylighting. Fiber optic daylighting (FOD) systems are an evolving technology that may provide a solution for daylighting technology. These systems use fiber optics combined with solar light collectors to transmit daylight to spaces historically difficult to daylight, using sidelighting or toplighting strategies. This research aims to show the energy conservation capability and efficiency of FOD as compared to Artificial Lighting. Calculations will highlight efficiency and performance for the design concepts. These calculations are intended to show how much energy conservation can be achieved with better illumination from FOD as compared to lighting generated by solar power (PVC) system, for the same sun intensity captured by the sun collectors of the two systems and the same length of cable. Matlab / Simulink software was used in simulating the efficiency and performance for the design concepts

Modeling of Orthogonal Frequency Division Multiplexing (OFDM) for Transmission in Broadband Wireless Communications

Orthogonal Frequency Division Multiplexing (OFDM) is a multi carrier modulation technique that provides high bandwidth efficiency because the carriers are orthogonal to each other and multiple carriers share the data among themselves. The main advantage of this transmission technique is its robustness to channel fading in wireless communication environment. This paper investigates the effectiveness of OFDM and assesses its suitability as a modulation technique in wireless communications. Several of the main factors affecting the performance of a typical OFDM system are considered and they include multipath delay spread, channel noise, distortion (clipping), and timing requirements. The core processing block and performance analysis of the system is modeled usingMatlab

Design and Implementation of a Microprocessor Based Temperature Controller With Real Time Display

The objective of the project was to automate and control temperature for a server room. The system is allowed entry of a desired room temperature within a prescribed range and to exhibit overshoot and steady-state temperature error of less than 1 degree displaying the value in real time. The details of the design developed, based on a PIC18F452 microcontroller are described. Time, cost and energy are saved by delivering power efficiently using this system. It can be applied in industries, auditoriums, green house buildings, server rooms and nuclear facilities. It is shown that the solution requires broad knowledge drawn from several engineering disciplines including electrical, mechanical, and control systems engineering. Keywords: Temperature, Sensor, Display, Control, Microcontroller, Real Time

Flexibility for Internet Protocol Backbone Network for Airspace Management Agency Using Dense Wave Division Multiplexing (DWDM)

With the increasing emphasis on service quality in the network of Airspace Management Agencyin the world, coupled with the extensive growth in internet traffic globally it has become a necessity to enhance the backbone network of Airspace Agency with flexibility of Internet Protocol using the Dense Wave Division Multiplexing (DWDM). This is to enhance the backbone network with a resilience of IP-DWDM in case of failure. The IP-DWDM network merges the IP and optical layers making network flexibility possible. The measurement, analysis and evaluations of the backbone network were carried out using simulation method. The throughput, latency and data loss were evaluated and analyzed. The result obtained shows that the Dense Wave Division Multiplexing has relatively high throughput, low latency and less packet drop which resulted in high transmission rate over a long distance and low cost in running the network. The paper therefore, proposes the use of embedded flexibility of the network in achieving an increase in the efficiency and utilization of the bandwidth of the interconnecting core routers of the networks

Effect of Increasing Buffer Size on Prioritized Guard Channels with Queue during Call Traffic Congestion

Prioritized guard channel (PGC) assignment with queue was designed to reduce call dropping probability associated with a base station congested with handover call traffic. The Markov chain was used in the analysis of the PGC scheme and queuing discipline was FIFO for a PGC+MAHO scheme. Simulation was carried out using MATLAB. The results showed that increasing buffer size reduces call dropping probability which becomes discontinuous at some value of traffic arrival rate for each buffer size. It was found out that some queuing parameters such as queue product form becomes undefined at an arrival rate for a large buffer size. This limits the extent to which buffer size can be increased. System computational speed was also a contributory facto

Reduction of Routing Delay in an Enterprise Network using Dynamic Multipoint Private Network

The more integrated networks are with the internet, the more our security concerns grow. Virtual Private Networks (VPNs) have been used to solve the problem of internet security. As more locations need to be securely connected, more configurations and greater complexity are given to a network design. Dynamic Multipoint VPN (DMVPN) was used in this research with some supporting protocols to allow changing of Internet Protocol (IP) addresses of remote locations. It proves to be a very scalable VPN technique with minimal configurations and robustness. Lesser delay between two branches of an organization among other advantages, such as elimination of triangular routing, and dynamic changing IP addresses were achieved