Abstract: A signal selection and fault detection system receives multiple redundant sensor input signals that are processed through an equalizing and selecting network which outputs the midvalue signal. The system provides a variable fault monitoring threshold that provides the ability to detect for oscillatory faults among input signals that are less than 10% of static tracking tolerances for the inputs, while also assuring that nuisance fault detections are very improbable. The system provides a variable equalization rate that assures satisfactory blocking of oscillatory faults under dynamic conditions when signal disagreements are increased by gain tolerances between the input signals, and maintains high signal resolution of the output under such dynamic conditions. The system also provides cross-channel equalization of the selected midvalue signal in all operating channels to assure that all channels provide the same steady state output for only two input operation, while also maximizing fault blocking capability.

Abstract: Multiple redundant sensor signals are processed through an equalizing and selecting network which outputs the midvalue signal and eliminates all null offsets occurring among signals. Errors due to drift in a signal are minimized by bounding the output to the limits of the remaining redundant signals. Faults of both a high and low frequency nature are detected resulting in the isolation of the appropriate signal channel.