KEYWORDS: Signal to noise ratio, Signal detection, Interference (communication), Electromagnetism, Signal processing, Electronic filtering, Filtering (signal processing), Nonlinear optics, Sensors, Linear filtering
In this paper, we report on efforts to develop signal processing methods appropriate for the detection of man-made electromagnetic signals in the nonlinear and nonstationary underwater electromagnetic
noise environment of the littoral. Using recent advances in time series analysis methods [Huang et al., 1998], we present new techniques for detection and compare their effectiveness with conventional signal processing methods, using experimental data from recent field experiments. These techniques are based on an empirical mode decomposition which is used to isolate signals to be detected from noise without a priori assumptions. The decomposition generates a physically motivated basis for the data.
We describe a concept in which an array of coupled nonlinear
oscillators is used for beamforming in phased array receivers. The
signal that each sensing element receives, beam steered by time
delays, is input to a nonlinear oscillator. The nonlinear
oscillators for each element are in turn coupled to each other.
For incident signals sufficiently close to the steering angle, the
oscillator array will synchronize to the forcing signal whereas
more obliquely incident signals will not induce synchronization.
The beam pattern that results can show a narrower mainlobe and
lower sidelobes than the equivalent conventional linear
beamformer. We present a theoretical analysis to explain the beam
pattern of the nonlinear oscillator array.
Conference Committee Involvement (2)
Advanced Signal Processing Algorithms, Architectures, and Implementations XVI
15 August 2006 | San Diego, California, United States
Advanced Signal Processing Algorithms, Architectures, and Implementations XIV
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