Dept. of Electronics

and India about 140 million years ago, and consequently the opening of the Indian Ocean, is thought to have been caused by heating of the lithosphere from below by a large plume whose relicts are now the Marion, Kerguelen and Réunion plumes. Plate reconstructions based on palaeomagnetic data suggest that the Indian plate attained a very high speed (18-20 cm yr 21 during the late Cretaceous period) subsequent to its breakup from Gondwanaland, and then slowed to 5 cm yr 21 after the continental collision with Asia 50 Myr ago 1,2 . The Australian and African plates moved comparatively less distance and at much lower speeds of 2-4 cm yr 21 (refs 3-5). Antarctica remained almost stationary. This mobility makes India unique among the fragments of Gondwanaland. Here we propose that when the fragments of Gondwanaland were separated by the plume, the penetration of their lithospheric roots into the asthenosphere were important in determining their speed. We estimated the thickness of the lithospheric plates of the different fragments of Gondwanaland around the Indian Ocean by using the shear-wave receiver function technique. We found that the fragment of Gondwanaland with clearly the thinnest lithosphere is India. The lithospheric roots in South Africa, Australia and Antarctica are between 180 and 300 km deep, whereas the Indian lithosphere extends only about 100 km deep. We infer that the plume that partitioned Gondwanaland may have also melted the lower half of the Indian lithosphere, thus permitting faster motion due to ridge push or slab pull.

The development of the Digital Video Broadcasting (DVB) standards was started in 1993 [1]. DVB is a transmission scheme based on the MPEG-2 standard, as a method for point to multipoint delivery of high quality compressed digital audio and video. It is an enhanced replacement of the analogue television broadcast standard, as DVB provides a flexible transmission medium for delivery of video, audio and data services [2]. The DVB standards specify the delivery mechanism for a wide range of applications, including satellite TV (DVB), cable systems (DVB) and terrestrial transmissions (DVB) [3]. The physical layer of each of these standards is optimized for the transmission channel being used. Satellite broadcasts use a single carrier transmission, with QPSK modulation, which is optimized for this application as a single carrier allows for large Doppler shifts, and QPSK allows for maximum energy efficiency [4]. The major difference between DAB and DVB is the larger bandwidth used and the use of higher modulation schemes to achieve a higher data throughput. The DVB-T allows for three subcarrier modulation schemes: QPSK, 16-QAM (Quadrature Amplitude Modulation) and 64-QAM; and a range of guard period lengths and coding rates. This allows the robustness of the transmission link to be traded at the expense of link capacity. DVB is a Uni-directional link due to its broadcast nature. Thus any choice in data rate verses robustness affects all receivers. If the system goal is to achieve high reliability, the data rate must be lowered to meet the conditions of the worst receiver. This effect limits the usefulness of the flexible nature of the standard. However if these same principles of a flexible transmission rate are used in bi-directional communications, the data rate can be maximized based on the current radio conditions. Additionally for multiuser applications, it can be optimized for individual remote transceivers.

The development of the Digital Video Broadcasting (DVB) standards was started in 1993 [1]. DVB is a transmission scheme based on the MPEG-2 standard, as a method for point to multipoint delivery of high quality compressed digital audio and video. It is an enhanced replacement of the analogue television broadcast standard, as DVB provides a flexible transmission medium for delivery of video, audio and data services [2]. The DVB standards specify the delivery mechanism for a wide range of applications, including satellite TV (DVB), cable systems (DVB) and terrestrial transmissions (DVB) [3]. The physical layer of each of these standards is optimized for the transmission channel being used. Satellite broadcasts use a single carrier transmission, with QPSK modulation, which is optimized for this application as a single carrier allows for large Doppler shifts, and QPSK allows for maximum energy efficiency [4]. The major difference between DAB and DVB is the larger bandwidth used and the use of higher modulation schemes to achieve a higher data throughput. The DVB-T allows for three subcarrier modulation schemes: QPSK, 16-QAM (Quadrature Amplitude Modulation) and 64-QAM; and a range of guard period lengths and coding rates. This allows the robustness of the transmission link to be traded at the expense of link capacity. DVB is a Uni-directional link due to its broadcast nature. Thus any choice in data rate verses robustness affects all receivers. If the system goal is to achieve high reliability, the data rate must be lowered to meet the conditions of the worst receiver. This effect limits the usefulness of the flexible nature of the standard. However if these same principles of a flexible transmission rate are used in bi-directional communications, the data rate can be maximized based on the current radio conditions. Additionally for multiuser applications, it can be optimized for individual remote transceivers.

This paper presents an application of the GSM technology. Using the public GSM networks, a mobile phone based home surveillance system has been designed. The system automatically sends sms messages to specified phone / phones in case any door or window is opened by some intruder. The system also allows the homeowner monitoring and controlling the electrical home appliances via the mobile phone by sending commands in the form of SMS messages and receiving the appliances status. Virtual control panel is realized using VB on windows 98. Electronic circuit to control security and electrical appliances is interfaced to PC using PCL-812 Lab card. This home surveillance system has been tested and found to very effective in security control as well as controlling and monitoring electrical home appliances virtually from any place.

This paper presents an ultra-low-power single-chip sensor-node VLSI for wireless-sensor-network applications. A communication centric design approach has been introduced to reduce the power consumption of the RF circuits and the entire sensor network system, through a vertical cooperative design among circuits, architecture, and communication protocols. The sensor-node LSI features a synchronous media access control (MAC) protocol and integrates a transceiver, i8051 microcontroller, and dedicated MAC processor. The test chip occupies 3 × 3 mm 2 in a 180-nm CMOS process, including 1.38 M transistors. It dissipates 58.0 μW under a network environment.

WSN is wireless sensor network which consist of numbers of nodes. Transceiver has main role in WSN node. Transceiver consists of both transmitter as well as receiver. Power amplifier, low noise amplifier, mixer, voltage control oscillator are the main block of Transceiver. Power amplifiers are a key part of RF transmitters. 2.4 GHz RF CMOS power amplifier implemented with SMIC 0.13μm is proposed. After power amplifier low power 2.4 GHz RF CMOS mixer with SMIC 0.13μm is proposed. The main aim is to improve the gain, increase the linearity and figure of merit.

Wireless sensor network (WSN) consists of tiny sensor nodes with sensing, computation and wireless communication capabilities. Now days, it is finding wide applicability and increasing deployment, as it enables reliable monitoring and analysis of environment. Lifetime maximization relates with various factors such as throughput, end to end delay, lifetime parameter such as time, output, packet delivery rates, no. of nodes, nodes efficiency and operating frequency to operate and relate each parameter. Balancing energy consumption and prolonging network lifetime are open challenges in Wireless Sensor Networks. In the research field of WSNs how to reduce the energy consumption of WSN so that the lifetime of WSN can be prolonged is one of the hottest spots. In this paper we survey various methods to maximize the lifetime of wireless Sensor Networks highlighting their objective, features, complexity etc.

A Kalman filter is an optimal estimator that infers parameters of interest from indirect inaccurate and uncertain observations. It is recursive so that new measurement can be processed as they arrive. In this paper first we take the input image then add noise to the input image, then give coefficient of noisy image to the VHDL module of kalman filter and finally compare the original input image with filtered image. Kalman filtering method indicates considerable improvement in SNR. The final filtered image shown an approximately 9-dB improvement in SNR with minimal loss of edge information.

Wireless sensor network is system use for purpose of data acquisition from area or field which is difficult task for human being. Wireless sensor network is full of challenge from point of view of application and proper utilization of resources like energy source provided in sensor node. To reduce the load of system i.e. to utilize resources of system properly, this paper present new hierarchical routing protocol to deal with application embed with multiple task in which load of main cluster head is balances with the help of supporting cluster head. Proposed protocol deal with both stationary and dynamic or moving sensor nodes. Where supporting cluster head come in existence only when load of main cluster head exceed the threshold. Sub node of cluster will not have any idea regarding supporting cluster head which help to reduce processing phase of system. Performance of proposed protocol is analyze by comparing it with LEACH protocol with the help of parameters like life time of sys...

Power consumption and size are the main challenges faced when designing radio transceivers for wireless sensor networks (WSN). The increasing growth of short range wireless sensor networks has led to increase demand of compressed radio frequency (RF) device with low power utilization and better phase noise design. The voltage control oscillator (VCO) is the center block of RF systems and critical sub-block in WSN communications transceivers to achieve the desired frequency up-conversion and down-conversion for modulation and demodulation respectively. The proposed VCO is designed with two series MOS in a switch manner using current reuse methodology and the PMOS varactor tank in inversion-mode. The VCO proposed in the paper consists of a single on chip inductor with four MOS transistors that simplify the schematic, shrink the chip area remarkably and low down the power consumption to a great extent as well. This paper presents an advanced low power low noise 2.45 GHz current reuse -...

Power consumption and size are the most important challenges faced when designing radio transceivers for distributed wireless sensor networks (WSN). The explosive growth of short range wireless communication systems has led to high demand of compact radio frequency (RF) circuit with low power and low phase noise design. As voltage control oscillator (VCO) is the core block of RF systems and critical sub-block in WSN communications transceivers. Although significant amount of research work has been carried out on VCOs, there still remains room for improvement and many new circuit schemes and new interpretation of phase noise can be found in recent times. This paper presents an idea of a low power low noise and highly miniaturized current reuse LC tank RF VCO design methodology.

WSN is wireless sensor network which consist of numbers of nodes. Transceiver has main role in WSN node. Transceiver consists of both transmitter as well as receiver. Power amplifier, low noise amplifier, mixer, voltage control oscillator are the main block of Transceiver. Power amplifiers are a key part of RF transmitters. 2.4 GHz RF CMOS power amplifier implemented with SMIC 0.13μm is proposed. After power amplifier low power 2.4 GHz RF CMOS mixer with SMIC 0.13μm is proposed. The main aim is to improve the gain, increase the linearity and figure of merit. Keywords: power amplifier; mixer; RF CMOS; WSN; operating frequency; Transceiver.

The IEEE 802.11 is a standard for wireless LANS and wireless multi-hop adhoc networks.But the fact is that the performance of IEEE 802.11 drops dramatically in terms of throughput and delay as the network traffic goes up particularly when the station reaches to the saturation state. IEEE 802.11 supports two modes of operation: Distributed Coordination Function (DCF) and Point Coordination Function (PCF).This paper presents the unfairness of IEEE 802.11 protocol when deployed in multi-hop networks scenario. The basic method to access IEEE 802.11 MAC Layer is DCF mode and it is based on CSMA/CA. In this paper we have shown that by the use of simple distributed algorithm that can be placed in this case to approximate ideal scheduler like round robin so as to provide the fair access to all flows in the network. So from the results of simulation it is clear that this approach proves to be best on the fairness standard. In addition by reducing the number of collisions we have also increas...

Electrocardiogram (ECG) analysis plays vital role in diagnosis of heart diseases. In order to avoid erroneous conclusions, it is of utmost importance that only sinus rhythms are present in the ECG Signal. Therefore, preprocessing of the ECG signal is necessary before utilizing it for diagnostic purpose [9]. In an ECG signal all kind of noises may occur simultaneously, two major noises that can be contaminated in ECG signal are baseline wander and power line interference, removal of those two noises from an ECG signal is a classical problem. In this paper digital filtering based simple approach is proposed for the removal of baseline wander and power line interference. Performance evaluation of this algorithm is done on recorded ECG signals by holter recorder and MIT-BIH database. Validation of proposed algorithm indicates that it effectively removes baseline wander and power line interference and preserves useful clinical information.