TITLE: Chaotic Detector to Identify Weak Signals in the Presence of Gaussian Noise

SPEAKER: Dr. John Shields

DATE and TIME: October 11th, 2018 – Lunch will be served at 11:30 a.m. and presentation starts at 12:00 p.m. 

PARKING: Free visitor parking is available in designated areas on the second level of the parking deck next to the GTRI conference center building. Pull up to the gate arm and it should lift up once you near it. Then you can proceed up the ramp to the second level.

RSVP: By 6:00 p.m. on October 10th, 2018 at

LOCATION: GTRI Conference center located at 250 14th St NW, Atlanta, GA 30318.


The detection of very weak signals in the presence of background noise is a challenge of significant
interest for many radar, sonar, and communications applications. Standard tools such as the Matched
Filter perform poorly when the signal-to-noise ratio (SNR) is less than about -10 or -20 dB. Therefore,
the detection of these low SNR signals requires the development of more sophisticated signal processing

The chaotic detector is a non-linear detector that is designed to couple to a weak signal of a given
frequency, while (in principle) remaining immune to the background noise. In particular, the non-linear
Duffing Equation, which describes the motion of a damped, driven harmonic oscillator, has proven to be
exceptionally well-suited to the detection of weak sinusoidal signals with SNR less than -30 dB.

This presentation will discuss the design, performance, and limitations of multiple implementations
of Duffing detectors.


Dr. John Shields received his PhD in High Energy Physics from the University of Virginia in
2004. Shortly thereafter, he was awarded a competitive U.S. Department of Energy Fusion Energy
Sciences Postdoctoral Fellowship to simulate optical diagnostic tools for plasmas in the Compact
Toroidal Hybrid plasma experiment at Auburn University.

Dr. Shields joined the GTRI Advanced Concepts Laboratory in 2007 and initially focused his
research on the computational simulation of plasmas and electromagnetic materials. His work has
included modeling atmospheric plasmas, photonic and phononic crystals, and high power microwave
sources. More recently, his interests have shifted to applications of statistical signal processing and
machine learning to electronic warfare, particularly in the area of adaptive Doppler radar.

IEEE ATLANTA ComSoc contact email:


TITLE: Commercial Software Defined Radios

SPEAKER: Dr. Rajib Bhattacharjea

DATE and TIME: April 12th, 2018. Lunch will be served at 11:30 a.m. and presentation at 12:00 p.m.