Note: As of 2015, a lot of the information on this page is somewhat dated, but accurate.

Projects

I like working in multidisciplinary areas. At college (University of Michigan, BITS) as well as in research institutions like NCRA-TIFR and IGCAR, I have worked in situations where I often had to learn some science for a particular area, and then apply my knowledge in electronics and computer programming to design applications for use in that area. Some of my projects are listed below.

Pitch Detection and Tracking

(Multimedia Codec Division, Nokia Research, Bangalore, India)

Pitch contours enable audio files to be analyzed and compared with respect to several parameters, and serve as a very useful form of metadata, specially for applications that construct lists or similar songs, etc. In this project, various algorithms were used for analyzing instrumental and sung audio tracks, and for generating the pitch contours corresponding to these tracks. Modules for pitch detection, tracking, and writing to a database were constructed in Python.

Design of a Software Radio System

(under Dr.K.R Anupama, BITS Pilani (Goa), India )

This project involves demodulation of OTA capture data using the GNURadio module in Python. Pre-recorded streams of FM and AM data are demodulated using GNURadio under Ubuntu Linux. Also, a proof-of-concept system for demodulation of AM/FM signals on a hardware DSP was implemented using the TMS320C6711 DSP manufactured by Texas Instruments.

BITS Goa Radio Telescope Project

(under Dr. Ashish Asgekar, BITS Pilani (Goa), India)

This project involved two of my favourite subjects , Digital Signal Processing, and Astronomy. The ultimate aim of the project was to get radio sky data at 72.6 MHz using an FPGA system interfaced with radio antennas, process the data to get information in the frequency domain, and try to make maps of the radio sky at this wavelength. Initially, we simulated data received from radio antennas and processed it, taking cross correlations and Fourier transforms for various signal-to-noise ratios. After this, a system for processing the data received by the system, using cross-correlation and Fourier transforms was designed, using the FFTW and PGPLOT C libraries on a Linux machine. We also designed a faster software correlator using lookup tables.


Some outputs

FFT of autocorrelation of a demodulated sample signal

Phase gradient

Phase gradient detection

Analysis of quasi-stellar objects using radio and optical data from wide area surveys

(Under Dr. Yogesh Wadadekar, NCRA-TIFR, Pune, India)

This project involved getting radio intensity from the radio sky survey FIRST and optical data from the Sloan Digital Sky Survey for a select list of quasi-stellar objects. The first part of the project using SQL queries for collecting the data for the same objects from two different sky surveys. The second part involved analysing the obtained data to find the correlation between the optical and radio properties of Quasi-stellar objects. This project was a part of the Visiting Students Research Program that I attended at NCRA-TIFR, and a talk that I gave on the same can be found here.

Radio loud fraction by magnitude

Radio loud fraction of quasars v/s magnitude

Automated Hall Effect Measurement System

(Under K.Suresh, Scienctific Officer, IGCAR Kalpakkam, India)

This project involved the design of a system that, using the principle of the Hall Effect, automatically made resistivity and magnetic field measurements and then calculated the sheet density of charge carriers in semiconductors. For a real -world semiconductor sample, the van der Pauw method of resistivity measurement (shown below) is used.

figure of Van der Pauw Method

For this purpose, we interfaced a nanovoltmeter (for measuring Hall voltage across the sample), a current source (for passing current through the sample), a high-voltage power-supply controlling an electromagnet (which generated the magnetic field), and a gaussmeter (for measuring the strength of the magnetic field through the sample) to a control computer using a GPIB bus system. Also, a switching card using a USB module, logic gates and relays which ensured that these instruments took particular measurements when given a particular command sequence from the computer. Measurements were taken using LabVIEW.

Hall effect setup

Software | Hardware

Along with Mr. K.Suresh, I presented a paper on this design at the International Conference on Trends in Intelligent Electronic Systems at Chennai in 2007. The paper can be downloaded here.