Wireless Communications Experience

Iowa State University, Ames, Iowa (8/84 to present)
Associate Professor

Wireless Channel Security. Research in countermeasures for network attacks in the areas of Denial-of-Service, Spoofing, and Position-Location (Research Start-up)
Interference Rejection in Narrowband Communication Systems. The behavior of cascaded and crosscoupled estimators for separating AM and FM/PM signals was studied and theoretical results were derived. (Sponsor: Rockwell International)
Digital FIR/IIR Filter Design of Arbitrary Passbands. A design method was developed for FIR digital filters with complex coefficients that approximate non-conjugate symmetric frequency responses of arbitrary amplitude and frequency shapes. The method was also adapted for the design of differentiators and Hilbert transformers. This software is used to develop communication transmitter and receiver digital filters without the constraints of linear phase (Parks-McCellan) or conjugate symmetry. (Sponsor: Rockwell International)
Digital Radio Techniques. Sigma-Delta A/D converters and generalized digital signal processing for communication receivers. (Sponsor: Texas Instruments)
HF Radio System Networking. System design of a frequency-hopping HF radio network. (Sponsor: Radio Corporation of America (RCA))
Reception Improvement of Amplitude Modulated Signals by Frequency Diversity Reception and Digital Deconvolution. Split-Spectrum Independent-sideband receiver signal processing design for international shortwave broadcast reception improvement.

King Radio Corporation, Olathe, Kansas (8/80 to 7/84)
Principal Engineer and Lab Leader

Research and development of the company's first automated TCXO design and manufacturing capability. Precision of better than 1ppm over a temperature range of -55C to +90C with a unit production cost of $70.
Signal processing analysis and design of a low-cost VLF-Omega navigation sensor.
Developed a two-port network theory for the matching of high VSWR antennas to high-power transmitters with coaxial feed lines.
Prepared system design specifications for long range navigation and HF communication equipment.

Rockwell International. Cedar Rapids, Iowa (1/79 to 7/80)
Avionics Advanced Technology
Senior Engineer/Scientist V

Project Manager for the Phase-I NAVSTAR/GPS-based Surface Vehicle Navigation Study performed under contract to General Motors. The first civil GPS application at Rockwell. Managed a 5-engineer technical team and did all planning, scheduling, and cost analysis. Also did the complete system and signal processing design and supervised prototype mechanical and electrical design.
Wrote a tutorial paper on anti-jam system design widely used as a resource for system design engineers. Topics covered were spread spectrum gain, anti-jam signal processing, and null steering antennas.

Rockwell International. Cedar Rapids, Iowa (3/76 to 12/78)
Avionics Advanced Technology
Senior Engineer/Scientist IV

Signal Processing and Communication System Analyst, Global Positioning System (NAVSTAR/GPS) User Equipment Development Program, Phases I and IIa. Project leader for receiver subsystem acceptance testing. Detailed analysis of signal processing in GPS receiver. Design and specification of statistical detection and acquisition algorithms employing non-central Chi-square statistics and sequential detection algorithms. Wrote several technical reports on satellite acquisition techniques and statistics. Assisted with extensive receiver testing and wrote reports on results. Assisted with receiver system design and performance analysis for GPS Phase-IIA proposal. Led a special design team effort for the Manpack that resulted in meeting schedule and design goals.

1978 Spectral Analysis for Noisy Sampled-Data Systems. Ph.D. Dissertation on spectral analysis for signals in noise - the Maximum Entropy Method.

University of Iowa. Iowa City, Iowa (6/73 to 6/74)
Department of Physics and Astronomy
Physics Research Center
Research Engineer

Design of RF Systems and Circuits to be used in Radio Astronomy Research. Designed and developed an SSB receiver and quadrature signal correlator to be used as a solar burst spectrum analyzer. Designed and developed a low-noise UHF preamplifier using state-of-the-art broadband amplifiers and low noise field-effect transistors.

1973 Noise Theory for Receiving Systems and Circuits. Masters Thesis on noise theory and measurements in communication systems.

Ruscom Engineering, Ames, Iowa (1971 to 1975)
Consulting Engineer (Self-Employed)

Design, development and test of hardware systems and circuits. Analog RF and audio system and circuit design, development, and test for a municipal emergency callbox system (fire, police). Propagation studies for low-frequency FM along urban fire department current loops.

Collins Radio Corporation, Cedar Rapids, Iowa (7/66 to 7/70)
RF Design Engineer

Low-noise receiver front-end technology and design providing design and development engineering to projects requiring high-technology receiver front-ends. Conception, design, development, and fabrication of a 100 MHz field-effect transistor analyzer for use in evaluating preamplifier designs. Participated in a Navy sponsored study on the future of microminiature technology for UHF RF preselectors and co-authored the technical reports. Conducted a study of the noise performance and noise measurement errors for the TACSATCOM receiving system. Project engineer for the design and development of the low-noise VHF preamplifiers and low-loss helical resonator filters used in the TACSATCOM receiving system. Project engineer for the design and development of the self-test and local oscillators for the Collins 621-A5 aircraft transponder.