Electrical and Electronics

In this paper, we have presented a wide range phase locked loop (PLL) based frequency synthesizer using a voltage tuning variable length ring oscillator (RO). The frequency of the used ring oscillator can be changed dynamically from one frequency to another frequency by changing the length of the oscillator electronically. An analog frequency tuning mechanism is also introduced here to make it suitable for applications in PLL based systems. The proposed PLL based frequency synthesizer can successfully synthesize different harmonics (Nf_r ) of the reference signal (f_r ) within the lock range of the oscillator. The experimental results from a prototype hardware electronic circuit are presented here to support the validity of the proposed architecture of the RO and the frequency synthesizer.

A linear adaptive beamforming structure consists of an antenna array and a digital signal processor to adjust adaptively its weight according to the particular criterion and adaptive algorithm. There are many criteria and adaptive algorithms to minimum co-channel interference (or multi-access interference).Different Algorithms (S.Strergiopoulos, 2001& Joseph C. Liberti, et al, 1999) are employed to determine the complex weights of the signal and to produce narrow beams toward intended users and deep nulls in the direction of interference.

Network-on-Chip (NoC) paradigm allows designers to integrate efficiently more intellectual properties (IPs) into a single chip system. However, the power consumption has become one of the most critical issues for designing such large complex systems. Low power design can be achieved by scaling the voltage and frequency of the target components. The question is how to make the voltage-frequency scaling adaptable to the required performance of the system at run-time while reducing as much as possible the power consumption. This paper presents a novel solution for NoC architectures to reduce power consumption. As the communication traffic is not equally distributed over the network architecture, depending on the communication load, each router in the network will be applied with a corresponding voltage and frequency to minimize the power consumption while keeping necessary communication throughput.

A novel approach for designing Ultra Low Power and wide dynamic range circuit for multiplexing analog signals is presented. The design operates in weak inversion (Sub threshold) region and uses Source - Coupled Logic (SCL) circuit. The bias current of the SCL gates is varied to scale down linearly the power consumption and the operating frequency. The multiplexer design employs CMOS transistors as transmission gate with dynamic threshold voltage. The design exhibits low power dissipation, high dynamic range and good linearity. The design was implemented in 180 nm technology and was operated at a supply voltage of 400 mV with a bias current ranging in the order of few pA. The ON and OFF resistance of the transmission gate achieved were 27 ohms and 10 M ohms respectively. The power dissipation achieved is around 0.79 µW for a dynamic range of 1µV to 0.4 V.

Software Engineering upholds the productivity of quality software products that meets the customer requirements. Requirements engineering ensures the customer satisfaction through the selection of requirements through elicitation processes. Requirement elicitation promotes prioritizing a set of requirements that enables the stakeholders for conformance to the requirements to be built. Requirement prioritization process solves critical decision making problems towards the selection of requirements among group of inappropriate requirements. The main objective of the comparison of the prioritization techniques concludes the differences between them in terms of cost and time. This paper compares and elaborates the prioritization technique that provides a deep study of their constraints, objectives and selection basis of the requirements.

The distribution automation system, should be the relationship between the different parts, this connection is performed by the telecommunication system. This study is based on a descriptive analysis and use of available resources to analyze automation telecommunication , and how it acted. Results indicated that collected information, tools and measuring equipment, as well as status indicators, this data includes voltage lines, switch status and key, and the temperature of the transformer and is, by means of relays digital, CT, PT, PI, or error detection, etc., collected, and for the electrical signal, is ready. The instrument is needed, to the various data collected, and ready to send. The device should be able to, such as terminal information act, and electrical signals different, the voltages and current levels vary in a range acceptable, and to send ready, and at the same time be able to signal receive operation also , to apply to the equipment, to reach the desired voltage level. The device, remote terminal units, or the so-called RTU, called. Telecommunication system, should be able to kind of adjustment between the data created. The data on the one hand, the path between the terminal and the control center to travel. Information, telecommunication system, some changes are to transfer from the environment to be prepared. These changes are known to act modulation. After sending the photo changes based on the signal, the signal becomes understandable message back into shape.

Due to economic reasons arising out of deregulation and open market of electricity, modern day power systems are being operated closer to their stability limits. Maintaining voltage stability and specified voltage levels at all nodes in a large & heavily loaded Power network is a critical & challenging task for power engineers. A number of different approaches have been reported in papers for improvement of voltage stability. In this paper a method for improving voltage stability in a power network has been suggested based on Network Reconfiguration approach. Network Reconfiguration is intended to enhance the voltage stability by determination of switching options that maximizes voltage stability for a particular set of loads and is performed by altering the topological structure of the system. In this paper, reconfiguration of a power network is achieved by addition of new power lines to the existing network. The paper reports an application of ANNs in voltage stability enhancement. A generalized ANN model has been proposed for enhancement of voltage stability under varying load conditions. Training data sets for ANN training is generated by varying both real and reactive loads at the buses. An IEEE-14 Bus system considered to demonstrate the performance of the developed ANN model. The proposed ANN model is trained using conjugate Gradient Descent Back-propagation Algorithm and tested by applying arbitrary input data. The test results of the ANN model are found to be closely matching of the results obtained by off-line simulation.

The impact of distributed generation in the grid network of the Nigerian South-South Region is studied in this paper. DG capacity installation in the network was modelled using NEPLAN software. Reduction of network and transmission line losses as well as minimisation of transmission line congestion and voltage profile improvement for the nodes of the network were observed in the results.

In a recent years, security for the thermal images are more necessary due to fast growing information technology. Here proposed an thermal image encryption based on histogram diffusion and permutation using chaotic map. As we know that histogram of thermal image distributed towards right (towards white pixel) and towards left (towards black). First step of proposed algorithm shift the histogram by mixing a random number. After that resultant image undergo permutation process with the help of chaotic map followed block wise histogram diffusing. In next level, apply the bit plane permutation. At last XOR operation with random image to get thermal encrypted image. The simulation results shows that proposed algorithm achieves high security.

A variable frequency and variable phase function generator with three outputs of (1) reference f_O (2) lead phase f_O + Æ₁ and (3) lag  phase f_O - Æ₂, is described in this paper. The leading phase difference Æ₁ is continuously adjustable over 0 to 180^o by an input control voltage V_C1 and the lagging phase difference Æ₂ is also continuously adjustable over 0 to -180^o by an another input control voltage V_C2, independent of frequency of operation of the function generator which can be set by a third control input dc voltage –V_I