Communications: electrical – Condition responsive indicating system – Specific condition
Patent
1996-07-29
1998-04-14
Swarthout, Brent A.
Communications: electrical
Condition responsive indicating system
Specific condition
340551, G08B 1314
Patent
active
057397546
ABSTRACT:
The present invention is a magnetic sensor used with one or more frequency band pass filters and a logic circuit that produces a ("critical") signal that is used for enabling and disabling an external electronic circuit, e.g. a computer circuit. The magnetic sensor produces a signal when excited by an externally applied alternating current (ac) magnetic field. The external ac magnetic field can comprise one or more frequencies, each of which induces an electrical signal at the respective frequency in the sensor. Depending on the linearity of the sensor, one or more harmonic frequencies of the signal frequencies can also be induced in the sensor. One or more bandpass filters is connected to the magnetic sensor and each of the bandpass filters is tuned to filter the signal to select filtered signals, from the output of the sensor. A logic circuit is activated by one or more of the filtered signals or a combination of one or more of the signal frequencies. When the logic circuit is activated, a critical signal is applied to an electronic circuit to enable or disable the external electronic circuit.
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Brady Michael John
Cofino Thomas A.
Gambino Richard Joseph
Heinrich Harley Kent
Moskowitz Paul Andrew
International Business Machines - Corporation
Percello Louis J.
Swarthout Brent A.
Trieu Van T.
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