Research Abstracts
Design of a fast data transfer board.
This project was carried out at the Norwegian government Broadcating Facility
in Oslo, norway. The scope of the project was two-fold: 1) To finda way to transfer
daily broadcast logs onto various media at high data transfer rates and 2) To
do real-time signal processing of digitized analog data and transfer the results
directly to PC memory or disk. The two processing platforms involved were an IBM
AT compatible computer and a Motorola 56000 signal processing board. An interrupt
driven configuration was decided upon as being able to fulfill the system data
rate requirements with minimum complexity. The completion of the project involved
my designing the circuit, writing the software, providing a set of schematics,
the working hardware prototype, documentation, and an operating manual. Project
time was approximately 3 months
Data Acquisition and Analysis Program.
Recent biomedical investigations have shown that there are characteristics of
the T' segment of the QRST cardiac signal complex which indicate the onset of
fibrillation /cardiac arrest before signs of physical distress are observable
in the patient. As par of a Veteran Administration Hospital's investigation into
this phenomena, I designed an eight channel oscilloscope program for the IBM personal
computer which would allow real-time monitoring of the associated signals. Inan
effort to reduce the amount of data used in the analysis and signal processing,
an infinite-impulse response (IIR) filter was implemented to model the process.
Budgerigar (Parakeet) Training Device.
Designed a device to train parakeets as part of an investigation into the learning
theory of Budgerigars. It was found that if human speech were translated up in
frequency and repetitively presented to the birds the training period could be
reduced. I designed, developed and built a working prototype . The device recorded
human speech at normal speech rate, then repetitively output the speech at either
normal rate or twice normal rate. The desin incorporated on of the tapeless' silicon
voice recorder chips.
Speech Research.
Designed and implemented signal processing routines for speech processing. It
has been shown that vowels are more important for intelligibility than consonants
ant that as few as three cycles of a vowel are required for recognition. A large
part of my research involved investigation of ways to modify vowel duration.
Design of a programmable finite impulse response (FIR) Filter.
This FIR filter was designed as a subsystem for a digital Equipment Research 11/23
research minicomputer. This project required analysis of applicable filters, arriving
at a design topology, and prototyping an actual filter. In use, a particular frequency
response curve is synthesized for a desired hearing-loss model. From this frequency
response, the associated impulse response is calculated. The coefficients of the
impulse response are then downloaded from the minicomputer to the filter subsystem
as filter weight coefficents. The board also incorporates an analog-to-digital
(A/D) converter.
Exaust Gas Recirculation (EGR) Control System for a Liquid
Natural Gas (LNG) Vehicle.
This was a project as part of the requirements for an advanced control system
seminar. The objective was to research and develop an algorithm to control emissions
from a pickup truck which had been converted from petroleum fuel to liquid natural
gas. The truck participated in the Society of Automotive Engineers Liquid Natural
Gas Challenge'. An open loop controller was designed in addition to interface
circuitry, for driving the EGR valve. A working controller was developed along
with a project report. Project involved getting the EGR control map for the gasoline
engine then researching how to modify the map control points for use with natural
gas.
PIN-diode 4pst high-power 1800-3200 MHZ coaxial-cavity
switch.
Researched and designed a high-power microwave PIN-diode switch for a British
telecom company. This switch was designed to be mounted on a helicopter to allow
switching between one of four antennas during mobile broadcasts.
Ultra-wide bandwidth electronic warfare antenna.
An antenna was researched and designed which covered a frequency range from 2-18
GHz (9:1 bandwidth). The antenna was polarized at a 45 degree angle. This slant
45 polarization obviates the necessity for phase matching required to implement
full circular polarization while giving good performance at various orientations
of the antenna.
Four port, Dual-Polarization Anntenna Feed
Researched and designed a four-port, dual-polarization antenna feed for a collapsible
parabolic dish antenna as part of a Satellite News Gathering (SNG) system. The
feed was required to transmit on one of two frequencies at one polarization and
to receive at the same two frequencies with the orthogonal polarization. This
project also required the design of two waveguide bandpass filters.
Control System Design for Antenna Testing.
As part of the design procedure for antennas of all types-military and commercial-it
is necessary to verify certain performance characteristics: azimuth beamwidth,
elevation beamwidth, and gain. For circularly polarized antennas it is also necessary
to measure the ellipticity (variation of power ratio as the polarization of the
antenna under test is changed relative to a fixed polarization source). The antenna
under test is normally rotated through 180 degrees in the azimuthal plane. Then,
if an elevation measurement required, the elevation of the antenna is changed,
and the azimuthal measurements are performed again. In addition, it is usually
required that the antennas be tested at discrete frequencies over their entire
operating bandwidth. Normally it is required that the operator manually perform
all of these operations, which is a timely procedure. A control system was designed
which allowed entire test to be programmed and data recorded and saved.
High-Energy Physics.
Primary research and design projects involved the design and construction of measurement
electronics for monitoring ionizable gases used in detecting high-energy particles.
One particular detector incorporated a low-energy radiation source to monitor
the ionizable gas concentration. The detector was installed in-line with the gas
supply to the main particle detection chambers. The radiation source ionized some
of the gas supply, these ionized particles setting-up a current between the high-voltage
anode and the detector housing. This current was proportional to the concentration
of the ionizable gas. Also designed a photo multiplier tube amplifier circuit
board and packaging scheme.