Signal Corruption Research Articles

Expert system approach to electroencephalogram signal processing

The human electroencephalogram (EEG) is often corrupted by ocular artefacts (OAs) caused by the movement of the eyes and/or the eyelids, making the recognition of abnormal EEG signals more difficult. The removal of OAs using conventional signal processing is complicated by the similarity between abnormal EEGs and OAs, which can lead to corruption of the EEG signal. The paper describes the development of a novel approach that uses expert system techniques to differentiate OAs from genuine EEG signals, enabling OA removal to be applied only where appropriate, and ensuring that clinically relevant EEG information is left unaffected.

Adaptive rematrixing of matrixed audio signals

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EFFICIENT TRANSIENT SIMULATION OF DISTRIBUTED INTERCONNECTS

The electrical performance of high‐speed integrated circuits and digital networks strongly depends on the behavior of interconnects between various components of these systems. The prediction of such performance can only be achieved by the used of computer‐aided design and simulation tools. The simulation of high‐speed digital circuits has gained a significant role in the past few years since it is critical in the evaluation of noise levels, signal corruption and signal delay in fast switching circuits. This paper explores the various aspects and techniques for transmission line simulation; in particular, two different methods are described: the scattering parameter method and the optimal method.

Adaptive technique for three-dimensional MR imaging of moving structures.

The authors describe an adaptive motion correction method for three-dimensional magnetic resonance (MR) imaging. Three-dimensional imaging offers many advantages over two-dimensional multisection imaging but is susceptible to image corruption due to motion. Thus, it has been of limited use in the imaging of mobile structures, and the relatively long imaging times required have hindered its use in patients who tend to move during imaging. The authors' technique uses interleaved "navigator" echoes to provide a measure of displacement for each image echo in the acquisition and then uses this information to allow correction of the image data. The theory for signal corruption due to motion and the correction scheme that follows from it are presented. This method can produce excellent results when the motion is correctly modeled.

Characterization of non-linear distortion in hearing aids using coherence analysis. A pilot study.

Coherence is a frequency-domain measure of linear dependence between input and output of a system, e.g. a hearing aid, and describes the cumulative effect of different forms of signal corruption, e.g. noise and non-linear distortion. From the coherence function, a general frequency-dependent signal-to-noise ratio can be derived. In this investigation, the applicability of this measuring technique is demonstrated in connection with non-linear distortion in hearing aids. The influence of hearing aid gain and automatic gain control is illustrated, with speech-shaped noise as input signal. For the three hearing aids tested. The gain setting influences the signal-to-noise ratio heavily due to non-linear distortion, especially near maximum gain. The introduction of automatic gain control reduces the effect of non-linear distortion somewhat at high gain settings.

The demonstration of restoring digital optical logic

Nonlinear all-optical circuit elements can be used to create indefinitely extensible optical logic. By the use of a 'lock and clock' architecture and an off-axis configuration of the power and signal beams, signal corruption can be avoided and standardized signal levels through cascaded devices maintained. Several loop circuits have been operated to demonstrate a simple 'optical classical finite state machine'.

Restoring Optical Logic: Demonstration Of Extensible All-Optical Digital Systems

We show experimentally how nonlinear all-optical circuit elements can be used to create indefinitely extensible optical logic. By using a "lock and clock" architecture and an off-axis configuration of the power and signal beams, we avoid signal corruption and maintain an undiminished signal level through cascaded devices. Several loop circuits have been operated to simulate an optical classical finite state machine.