Department of Electrical Engineering

Indian Institute of Technology Palakkad&nbsp;(IIT Palakkad or IIT PKD) is a public autonomous&nbsp;engineering&nbsp;and&nbsp;research&nbsp;institute located in&nbsp;Palakkad,&nbsp;Kerala. It was&nbsp;one of the five new&nbsp;IITs&nbsp;proposed in the&nbsp;2014 Union budget of India. The campus was inaugurated on 3 August 2015. The institute has 94 faculty, 978 students, and 63 non-teaching staffs.

IT Palakkad currently offers four-year Bachelor of Technology (B.Tech) and two years MS programmes in 8 different engineering disciplines including&nbsp;Computer Science, Electrical, Mechanical, Civil among others.

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IIT Palakkad

The channelizer in a software defined radio (SDR) base station extracts individual radio channels from the digitized wideband input signal at a very high sampling rate. The base station channelizer must be able to simultaneously extract multiple channels of non-uniform bandwidths corresponding to channel bandwidths of different communication standards. Reconfigurability and low complexity are the two key requirements in the SDR channelizer. A new reconfigurable filter bank (FB) architecture based on interpolation and masking technique for SDR channelizers is proposed in this paper. The proposed FB can be used for obtaining very narrow passband channels with extremely low complexity. Using a cascaded structure of the proposed FB, it is possible to extract channels of fractional passband widths by changing the interpolation factor. Design example shows that the proposed FB offers complexity reduction of 84% over the conventional per-channel (PC) approach. The proposed FB has been implemented and tested on Xilinx Virtex 2v3000ff1152-4 FPGA. Implementation results show that the proposed FB offers area reduction of 48.37%, speed improvement of 52.7% and power reduction of 75.9% over the PC approach. © Springer Science+Business Media, LLC 2010.

Journal of Signal Processing Systems

An area-efficient non-uniform filter bank for low overhead reconfiguration of multi-standard software radio channelizers

Recently, wireless medical body area network (WMBAN) plays an important role in remote cardiac patient monitoring, intelligent emergency care management system, and ubiquitous mobile healthcare applications. The wearable cardiac monitoring devices used in WMBAN system collect and transmit the vital signs of cardiac patients continuously. Generally, the use of WMBAN technology is restricted by size, power consumption, transmission capacity (bandwidth), and computational loads. Therefore, there is a great demand for low-complexity cardiac signal processing algorithms that can combat some of technical challenges related to pervasive healthcare computing with WMBAN technologies. In this paper, we present low complexity automatic QRS detection algorithm for long-term wearable cardiac monitoring device. The proposed QRS detection method first derives a smooth Shannon energy envelogram (SEE) of the first-derivative of the filtered ECG at the preprocessing stage. The major local maxima (LM) in the smooth SEE indicate the approximate locations of the R-peaks. In the second stage, the proposed HT-based peak-finding logic identifies the locations of the LM by detecting the positive zero-crossings in the HT of the SEE. Finally, the locations of the LM are used as guides to find the accurate locations of the R-peaks in the ECG signal. The proposed method is validated using the standard MIT-BIH arrhythmia database, and achieves an overall sensitivity of 99.86% and positive predictivity of 99.95%. Various experimental results show that the proposed algorithm significantly outperforms other well-known algorithms in case of noisy or pathological signals. © 2011 IEEE.

World University root node

2011 International Conference on Emerging Trends in Networks and Computer …

A simple and robust QRS detection algorithm for wireless medical body area network

Recently, wireless body area network (WBAN) plays an important role in remote cardiac patient monitoring, and mobile healthcare applications. Generally, the use of WBAN technology is restricted by size, power consumption, transmission capacity (bandwidth), and computational loads. In this paper, we therefore propose an automated cardiac event change detection for continuous remote patient monitoring devices. The proposed event change detection algorithm consists of two stages: i) ECG beat extraction; and ii) ECG beat similarity measure. In the first stage, the onset of each QRS complex is identified using the Gaussian derivative based QRS detector and the two heuristics rules. In the second stage, we employ the weighted wavelet distance (WWD) metric for finding the similarity between two ECG beats in wavelet domain. The WWD is the weighted normalized Euclidean wavelet distance between the wavelet subband coefficients vectors of the current and past ECG beats, where weights are equal to the relative wavelet subband energies of the corresponding subbands. The experimental results show that the weighted wavelet distance measure works substantially better than the conventional PRD and the wavelet based weighted PRD (WWPRD) measures under noisy environments. The proposed approach has been tested and yielded an accuracy of 99.76% on MIT-BIH Arrhythmia Database.

Proceedings of the 1st International Conference on Wireless Technologies for …

Automated cardiac event change detection for continuous remote patient monitoring devices

A novel soft transition push pull converter is proposed in this paper. The proposed circuit achieves loss-less switching for the two main and two auxiliary switches without increasing the main device current/voltage rating. A tapping in the isolation transformer is added for the purpose of commutation. The proposed circuit is capable of operation at elevated switching frequencies of several hundreds of kHz, in a range of line and load variations. Steady state performance, the operating principle and theoretical analysis is outlined for the proposed pushpull converter. The steady state conversion ratio and the equivalent circuit model is presented. Experimental results are presented which verifies the steady state performance of the converter. The experimental waveforms are in agreement with the theoretical. © 2011 IEEE.

IECON Proceedings (Industrial Electronics Conference)

Novel soft transition pushpull converter: Analysis, modeling, design and implementation

In this paper, we present an effective pre-processing algorithm for band selection approach which is an essential task in hyperspectral image analysis. The pre-processing algorithm is developed based on the average inter-band block-wise correlation coefficient measure and a simple thresholding strategy. Here, the threshold parameter is found based on the standard deviation of the average inter-band block-wise correlation coefficients. The performance of the proposed algorithm is validated using the standard hyperspectral database created by the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) sensor. By comparing the detected bands with ground-truth annotations, we observed that the proposed algorithm identifies the noisy and water absorption bands in the high-dimensional hyperspectral images. The proposed algorithm achieves the classification accuracy of 94.73%. © 2011 IEEE.

2011 International symposium on ocean electronics

An effective pre-processing algorithm for detecting noisy spectral bands in hyperspectral imagery

Network

Increasing Vertical Resolution of Three - Dimensional Atmospheric Water Vapor Retrievals Using a Network of Scanning Compact Microwave Radiometers

Two 24-pulse rectifier topologies based on phase shifting by conventional magnetics is proposed. Four 3-phase systems are obtained from a single 3-phase source using novel interconnection of conventional single- and 3-phase transformers. Phase shifts of 15° and 30° are made using phasor addition of relevant line voltages with a combination of single-phase and three-phase transformers respectively. The four three-phase systems are mutually displaced from each other by 15°. Each three-phase system feeds a 6-pulse diode rectifier and the four diode rectifiers are series cascaded to provide a 24-pulse dc output voltage. PSCAD based simulation and experimental results that confirm the design efficacy are presented. © 2011 IEEE.

2011 1st International Conference on Electrical Energy Systems, ICEES 2011

Novel topologies of 24-pulse rectifier with conventional transformers for phaseshifting

Adaptive modulation allows the system to adjust the signal modulation scheme depending on the signal-to-noise ratio (SNR) of the input signal. In this paper we propose a reconfigurable architecture for adaptive modulation. The proposed architecture uses the highest modulation scheme, when input is of high quality, giving the system more capacity. During a signal fade, the system can shift to a lower modulation scheme to maintain the connection quality and stability. The proposed architecture can be reconfigured for various quadrature amplitude modulation (QAM) and phase shift keying (PSK) modulations and it is an area and power efficient scheme compared to conventional adaptive modulation scheme which uses a velcro approach of realizing all the modulations in parallel. © 2011 IEEE.

Midwest Symposium on Circuits and Systems

Reconfigurable area and power efficient I-Q mapper for adaptive modulation

Low-complexity and flexible spectrum sensing is one of the challenging tasks in a cognitive radio (CR). Most of the work on energy-detection-based spectrum sensing presented in the literature employ a filter bank (FB) to split the wideband input signal into several subbands and detect the spectrum by computing the energy of subbands. However, for a mobile CR handset, a filter-bank-based spectrum sensing is not an area- and power-efficient scheme. In this paper, a novel spectrum-sensing scheme based on a reconfigurable digital downconverter (RDDC) and a reconfigurable filter based on coefficient decimation is proposed for mobile CR handsets, which has very low complexity and high flexibility compared to conventional FB approaches. The basic idea is to rotate the spectrum using an RDDC and filter the desired portion of the spectrum using the reconfigurable filter, which then results in very low complexity. The implementation results on Virtex-4 field-programmable gate array show that our method offers significant reductions in gate count, power consumption, and delay over conventional discrete Fourier transform FB-based spectrum sensing. © 2011 IEEE.

IEEE Transactions on Circuits and Systems II: Express Briefs

A low-complexity flexible spectrum-sensing scheme for mobile cognitive radio terminals

A new approach to implement computationally efficient reconfigurable filter banks (FBs) is presented. If the coefficients of a finite impulse response filter are decimated by M, that is, if every Mth coefficient of the filter is kept unchanged and remaining coefficients are replaced by zeros, a multi-band frequency response will be obtained. The frequency response of the decimated filter will have bands with centre frequencies at 2πk/M, where k is an integer ranging from 0 to M-1. If these multi-band frequency responses are subtracted from each other or selectively masked using inherently low complex wide transition-band masking filters, different low-pass, high-pass, band-pass and band-stop frequency bands are obtained. The resulting FB, whose bands' centre frequencies are located at integer multiples of 2π/M, is a low complexity alternative to the well-known uniform discrete Fourier transform FBs (DFTFBs). It is shown that the channeliser based on the proposed FB does not require any DFT for its implementation unlike a DFTFB. It is also shown that the proposed FB is more flexible and easily reconfigurable than the DFTFB. Furthermore, the proposed FB is able to receive channels of multiple standards simultaneously, whereas separate FBs would be required for simultaneous reception of multi-standard channels in a DFTFB-based receiver. This is achieved through a second stage of coefficient decimation. Implementation result shows that the proposed FB offers an area reduction of 41% and improvement in the speed of 50.8% over DFTFBs. © 2011 The Institution of Engineering and Technology.