Minnesota Mining and Manufacturing Company

Walter J ReMine

Joel R Dufresne

Eric A King-Smith

Anthony Michael Belka

Markers in different portions of the interrogation zone of an electromagnetic article surveillance system produce signals with waveforms of different character. In one embodiment, a false alarm minimization method determines the character of the waveform of the signal induced in the detection antenna. A requirement that signals with waveforms of different character be sensed provides greater confidence that the marker is passing through, as opposed to being near one portion of, the interrogation zone. Also, false alarms produced by stationary objects such as metallic door and window frames are eliminated. In another embodiment, the direction in which the marker passes through the interrogation zone is determined.

False alarm minimization and direction determination methods

An output limited electrical stimulator for biological tissue. Stimulus parameters, which can be modulated, are used to specify an electrical stimulus signal. A calculation element calculates the electrical charge which would be generated by an electrical stimulus signal defined by the modulated stimulus parameters. A limit element compares the calculated electrical charge against a predetermined standard and adjusts at least one of the stimulus parameters. An electrical stimulus signal is then generated using the adjusted stimulus parameters assuring that the electrical stimulus signal generated will have an electrical charge of not more than the predetermined standard.

Output limited electrical stimulator for biological tissue

An electrical stimulator for biological tissue having mode control. Circuit configuration parameters are stored during a certain circuit operation, such as power up. The circuit configuration parameters are checked during a second circuit configuration, such as, steady state operation and either modulated or unmodulated sets of stimulus parameters utilized to generate an electrical stimulus signal.

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Saint Paul, MN, United States of America

Walter J ReMine