Sequence Detection Using All-Magnetic Circuits

A technique is described for detecting specific sequences of pulses occurring on a net of input lines. This technique lends itself to realization in all-magnetic networks by the use of multi-aperture magnetic devices (MAD's). The resulting circuits are remarkably simple and reliable. Processing rates in excess of 100,000 characters per second may be achieved. Examples are given of systems using arrays of such detectors. One example involves a system for detecting handwritten characters which makes use of a special pen having the property of generating specific sequences of pulses as symbols are written. The second example relates to the problem of monitoring text for the detection of specific words (letter sequences) and phrases (series of sequences).