Communications: electrical – Condition responsive indicating system – Specific condition
Patent
1984-11-26
1987-04-21
Swann, III, Glen R.
Communications: electrical
Condition responsive indicating system
Specific condition
340551, G08B 1324
Patent
active
046600256
ABSTRACT:
A marker for an electronic article surveillance system is disclosed comprising a body of magnetic material with retained stress and having a magnetic hysteresis loop with a large Barkhausen discontinuity such that, upon exposure of the marker to an external magnetic field whose field strength in the direction opposing the instantaneous magnetic polarization of the marker exceeds a predetermined threshold value, there results a regenerative reversal of the magnetic polarization of the marker. An electronic article surveillance system and a method utilizing the marker are also disclosed. Exciting the marker with a low frequency and low field strength, so long as the field strength exceeds the low threshold level for the marker, causes a regenerative reversal of magnetic polarity generating a harmonically rich pulse that is readily detected and easily distinguished.
REFERENCES:
patent: 3765007 (1973-10-01), Elder
patent: 4075618 (1978-02-01), Montean
patent: 4222517 (1980-09-01), Richardson
patent: 4298862 (1981-11-01), Gregor et al.
patent: 4484184 (1984-11-01), Gregor et al.
patent: 4510489 (1985-04-01), Anderson, III et al.
patent: 4510490 (1985-04-01), Anderson, III et al.
Sensormatic Electronics Corporation
Swann III Glen R.
LandOfFree
Article surveillance magnetic marker having an hysteresis loop w does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Article surveillance magnetic marker having an hysteresis loop w, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Article surveillance magnetic marker having an hysteresis loop w will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-754802