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Instrumentation for wide bandwidth radio astronomy

Citation

Jones, Glenn Evans (2010) Instrumentation for wide bandwidth radio astronomy. Dissertation (Ph.D.), California Institute of Technology. http://resolver.caltech.edu/CaltechTHESIS:10122009-094525715

Abstract

Centimeter wavelength radio astronomy spans approximately two decades in frequency, from roughly 500 MHz to 50 GHz. In contrast, radio astronomy instruments have traditionally been limited to at most octave bandwidths, necessitating multiple instruments on a given telescope to cover a large fraction of the spectrum. This paradigm is infeasible for the next generation of telescopes, which will likely consist of hundreds to thousands of small dishes combined together in an array, because each receiver must be replicated for each element in the array. Therefore, wide bandwidth instrumentation must be developed for radio astronomy. This thesis presents a novel radio telescope with excellent system noise temperature and reasonable efficiency across an instantaneous fractional bandwidth greater than 4:1; amongst the widest ever demonstrated. This instrument illustrates that extremely wide bandwidth instruments are feasible, even in the presence of terrestrial interference. To make use of the enormous instantaneous bandwidth, a flexible, high performance, and cost effective digital signal processing system is also presented. Theory, design, and measurements of special purpose digital spectrometers built to minimize the effects of terrestrial interference are included. Aside from the practical advantages offered by wide bandwidth instrumentation, new scientific applications are also made possible. A special purpose system for performing detailed studies of giant radio pulses from rotating neutron stars (pulsars) is presented, along with demonstrations including some of the largest fractional bandwidth observations of these pulses made to date. This system includes a sensitive trigger which corrects for the dispersive effects of the interstellar medium in real time and a deep capture buffer optimized for observing repetitive transient phenomena. Measurements made using the trigger system at Arecibo Observatory are also presented to demonstrate the portability of the instrument.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:radio astronomy instrumentation, radiometer, digital signal processing, pulsar, giant pulses, dedispersion
Degree Grantor:California Institute of Technology
Division:Engineering and Applied Science
Major Option:Electrical Engineering
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Weinreb, Sander
Thesis Committee:
  • Rutledge, David B. (chair)
  • Weinreb, Sander
  • Vaidyanathan, P. P.
  • Readhead, Anthony C. S.
  • Kuiper, Thomas B. H.
  • Jarnot, Robert F.
Defense Date:25 September 2009
Author Email:jones_gl (AT) caltech.edu
Record Number:CaltechTHESIS:10122009-094525715
Persistent URL:http://resolver.caltech.edu/CaltechTHESIS:10122009-094525715
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:5295
Collection:CaltechTHESIS
Deposited By: Glenn Jones
Deposited On:21 Dec 2009 18:35
Last Modified:26 Dec 2012 03:18

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