Digital Signal Processing

1601 Submissions

[10] viXra:1601.0184 [pdf] submitted on 2016-01-17 06:43:47

Closed Loop Current Control of Three Phase Photovoltaic Grid Connected System

Authors: S.mallika, R.saravanakumar
Comments: 15 Pages.

The paper presents a closed loop current control technique of three phase grid connected systems with a renewable energy source. The proposal optimizes the system design, permitting reduction of system losses and harmonics for the three phase grid connected system. The performance of the proposed controller of grid connected PV array with DC-DC converter and multilevel inverter is evaluated through MATLAB-Simulation. The results obtained with the proposed method are compared with those obtained when using without current controller for three-phase photovoltaic multilevel inverter in terms of THD and switching frequency. Experimental works were carried out with the PV module WAREE WS 100, which has a power rating of 10 W, 17 V output voltages and 1000 W=m2 ir-radiance. The test results show that the proposed design exhibits a good performance.
Category: Digital Signal Processing

[9] viXra:1601.0182 [pdf] submitted on 2016-01-17 06:36:54

Optimal Design of Utility Interfaced Adaptive Solar Home Power Supply for Rural India

Authors: F. Karbalaei, M. Ranjbar, M. Kavyani
Comments: 6 Pages.

This paper compares the sensitivity method with a proposed nonlinear optimization method for setting of transmission network load tap changers (LTCs) as a preventive action for voltage instability. The aim of preventive actions is to increase voltage stability margin. In contrast to emergency actions, preventive ones implemented when the power system is stable. Thus, in calculation of a preventive action, in addition to increase stability margin, its effects on current operating point of the system must be considered. The sensitivity method is a linearized based method that uses the sensitivity of the loadability margin with respect to tap values. In the proposed optimization method, the tap values are calculated using optimal powerflow model. Two groups of variables are used in optimization problem: one group is related to base case (current operating point) and the other is related to the voltage stability boundary. By this work, the preventive actions do not cause undesirable changes in the system current variables.
Category: Digital Signal Processing

[8] viXra:1601.0181 [pdf] submitted on 2016-01-17 06:38:54

Life Time Enhancement of a Vacuum Interrupter for ac Smart Grid Applications

Authors: Asaad Shemshadi, Seyed Mohammad Tagi Bathaee, Sima Jalali Kashani
Comments: 11 Pages.

A smart grid is a modern system combined from power system and a network of computers which communicate and process the data achieved from measuring centers located in the power system network. They achieve specific local goals such as: enhancement the reliability, fast and easy control of power network and on-line monitoring. To control the blocks of a smart grid (entrance or outage), HV, MV and LV switching actions frequently are needed. Nowadays Vacuum interrupters (VI) are the most widespread switching devices especially in LV and MV voltage levels (up to 38 kV), through their reliability, heavy duty and maintenance free characteristics. In this article, the important lifetime factors of a VI for smart grid applications will be discussed. Further more the closing and opening speed of a proposed circuit breaker mechanism, as the most important lifetime factor, will be so planned that an important enhancement in the total lifetime of the VI is achieved.
Category: Digital Signal Processing

[7] viXra:1601.0180 [pdf] submitted on 2016-01-17 06:41:12

Zigbee Based Physiological Status Monitoring System

Authors: Mohit Kumar, Nirbhow Jap Singh, Sandeep Sharma
Comments: 10 Pages.

A lot of research has been carried out in the field of health care monitoring. In the recent years, development of wireless health care monitoring system has emerged as an area of research. The presented work falls under the health care monitoring system. Here the system monitors the patient continuously while simultaneously transmitting the physiological data to the doctors and other medical staff. The presented system is based on a dedicated communication protocol for sensor networks, ZigBee. The system has low cost, low power requirements and compact. The performance of the system is analysed for indoor and outdoor environment, under various conditions. It is observed that the system provides reliable monitoring and secure wireless transmission of the monitored data. Further it is observed that the current consumption of the system is 64.1 mA and 71.2 mA at the sensing node and coordinator respectively, when transmitted power is set at -18 dBm. The range of the system varies from 10m (indoor environment) to 30m (line of sight range in outdoor environment) at -18 dBm transmitted power, which is suitable for hospital environment.
Category: Digital Signal Processing

[6] viXra:1601.0139 [pdf] submitted on 2016-01-12 20:23:49

Design of Low Noise Amplifier at 435MHz in Sub-Micron Technologies Using Microwind Layout, Simulation and Parasitic Capabilities

Authors: Sai Venkatesh Balasubramanian, Thrikandiyoor Jayadev
Comments: 36 Pages.

The importance attached to filtering noise out of signal is growing significantly due to the requirement for faster and improved communication systems such as high-speed Internet access and wireless communication. The low-noise amplifier (LNA) is one of the major components in a wireless communication system, employed at the receiver side and is usually the immediate component to the Antenna in the receiver chain. This report attempts to explain the design of a low-noise-amplifier according to specifications. Using 0.35 μm technology to build the layout and the opes-source layout design tool - Microwind to simulate its operation, the performance of the LNA was optimized through the use of different circuit topologies and components. Based on the results obtained from simulation, the components were varied and sized to reach the desired results. The other aspect of the design process that was explored was effect of parasitics to assess the impact of physical structure and it's impact on the over all operation the LNA. To execute this task, the in-built parasitic extraction tool of Microwind was used. To a large extent, the objectives were met, thereby satisfying the requirements of the project. This include meeting the peak gain requirement of 22dB at the desired frequency of 435MHz, an input impedance of 50 ohms and a high output impedance with good noise removal characteristics. However, further study is proposed to explore the use of the Microwind design tool in designing complex analog circuitry and also using the circuit model in many other applications.
Category: Digital Signal Processing

[5] viXra:1601.0138 [pdf] submitted on 2016-01-12 20:35:01

Generation, Characterization and Applications of Digital Chaos

Authors: Sai Venkatesh Balasubramanian, Thadigotla Venkata SubbaReddy, Bommepalli Madhava Reddy
Comments: 30 Pages.

Chaos refers to complex behavior nonetheless deterministic, which arises in nonlinear systems. Chaos embodies two important principles: Extreme sensitivity towards initial conditions (also well-known as the butterfly effect.) Cause (reason) and effect (outcome) are not proportionate - Nonlinearity Chaotic signals serve as ideal candidates as carriers in secure communication systems. The present work proposes the generation, characterization and application of a ‘Digital’ chaotic signal using an iterative map. The present work implements the chaos generation using basic logical operations such as Exclusive OR (XOR) switching on four individual clocks with different frequencies and duty cycles. The above mentioned process is implemented in hardware level using XOR gates and 556 timer IC’s and in layout and simulation levels using Microwind respectively. Secondly Digital chaos generation is implemented in MATLAB and in Field Programmable Gate Array (FPGA) using Very high speed integrated circuits Hardware Description Language (VHDL). The generated chaotic signal is characterized using different parameters like Kolmogorov entropy (K2), Fractal Dimension (D2), Largest Lyapunov exponent (LLE), Phase plane portrait and Recurrence plot (RP). The main advantages of this work are 1. Simplicity - because of simple logical operations. 2. Security - due to high sensitivity of chaos to its initial conditions. Finally different applications of digital chaos have been explored.
Category: Digital Signal Processing

[4] viXra:1601.0137 [pdf] submitted on 2016-01-12 20:37:47

Digital Chaos based Pseudorandom bit Generator

Authors: Sai Venkatesh Balasubramanian, Thadigotla Venkata SubbaReddy, Bommepalli Madhava Reddy
Comments: 13 Pages.

Chaos refers to complex behavior nonetheless deterministic, which arises in nonlinear systems. Chaos embodies two important principles: Extreme sensitivity towards initial conditions (also well-known as the butterfly effect.) Cause (reason) and effect (outcome) are not proportionate - Nonlinearity Chaotic signals serve as ideal candidates as carriers in secure communication systems. The present work proposes the generation, characterization and application of a ‘Digital’ chaotic signal using an iterative map. The present work implements the chaos generation using basic logical operations such as Exclusive OR (XOR) switching on four individual clocks with different frequencies and duty cycles. The above mentioned process is implemented in hardware level using XOR gates and 556 timer IC’s and in layout and simulation levels using Microwind respectively. Secondly Digital chaos generation is implemented in MATLAB and in Field Programmable Gate Array (FPGA) using Very high speed integrated circuits Hardware Description Language (VHDL). The generated chaotic signal is characterized using different parameters like Kolmogorov entropy (K2), Fractal Dimension (D2), Largest Lyapunov exponent (LLE), Phase plane portrait and Recurrence plot (RP). The main advantages of this work are 1. Simplicity - because of simple logical operations. 2. Security - due to high sensitivity of chaos to its initial conditions. Finally different applications of digital chaos have been explored.
Category: Digital Signal Processing

[3] viXra:1601.0136 [pdf] submitted on 2016-01-12 21:02:53

Chaos Generation using Simple Microwave Circuitry

Authors: Sai Venkatesh Balasubramanian, Sri Kalyan Kambhampati
Comments: 21 Pages.

Chaotic signals are ideal nominees as carriers in secure communication systems. The present work proposes the generation, characterization and an interesting application of a Chaotic signal using an iterative map. The generation of a chaotic signal using simple microwave circuitry has been analyzed and implemented. By use of experiment, it was discovered that an ecient use of the nonlinearity in the semionductor device such as BFU725F/N1 NPN microwave bipolar junction transistor, can be used to generate a chaotic signal. The signal generated by the Gunn source is confirmed as a microwave pulse by operating it in the Negative Resistance region. The signal from the AFO is mixed with the Gunn source signal in the transistor producing a chaotic signal at the collector terminal. The bias voltage values are varied to characterize the output waveform. The parameters of a chaotic signal such as Lyapunov exponent, Kolmogorov Entropy and Fractal dimension are calculated for different waveforms obtained at different bias voltages. Frequency Spectrum analysis for both Gunn Source and the chaotic signal is done to ascertain the nonlinearity contributed by the transistor alone. Chaotic signal generated using simple microwave circuitry is more securable and reliable. Circuit complexity has been reduced very much which in turn reduces the cost. It has been observed that only the nonlinearity in the transistor is enough to generate a chaotic Microwave signal. The BFU725F/N1 transistor at 6.02 volts of Gunn bias gives a chaos signal. Chirping phenomenon is observed to be chaotic also.
Category: Digital Signal Processing

[2] viXra:1601.0135 [pdf] submitted on 2016-01-12 21:05:11

Electrical Chirping using Simple Microwave Circuitry

Authors: Sai Venkatesh Balasubramanian, Sri Kalyan Kambhampati
Comments: 21 Pages.

Chaotic signals are ideal nominees as carriers in secure communication systems. The present work proposes an interesting application of a Chaotic signal using an iterative map. By use of experiment, it was discovered that an ecient use of the nonlinearity in the semionductor device such as BFU725F/N1 NPN microwave bipolar junction transistor, can be used to generate a chaotic signal. Frequency Spectrum analysis for both Gunn Source and the chaotic signal is done to ascertain the nonlinearity contributed by the transistor alone. The effect of coupling of two transistors on the output waveform is observed using simulation. The waveform thus obtained is observed to be negatively chirped or down chirped. The characterization of the signal obtained with parameters mentioned above to know its nature is also done. Possible application of the above circuitry in the communication by checking the robustness of signal in a noisy environment is done using MATLAB. Chirping phenomenon is observed to be chaotic also.
Category: Digital Signal Processing

[1] viXra:1601.0099 [pdf] submitted on 2016-01-09 22:07:27

Analysis of Handoff Schemes in Wireless Mobile Network

Authors: Alagu S, Meyyappan T
Comments: 12 Pages.

This paper analyses the different traffic schemes for handoff handling and call blocking attempts. As traffic in mobile cellular networks increases, Handoffs will become an increasingly important issue and as cell sizes shrink to accommodate an increasingly large demand of services, newer more efficient handoff schemes need to be used. In this paper the author analyses the various Handoff schemes for multiple traffic system and simulates an ATM based wireless Personal Communication Network to implement the non-preemptive Measurement Based Prioritization Scheme (MBPS).
Category: Digital Signal Processing