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US4646015A
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Flux gate sensor with improved sense winding gating
Assignee: TomTom North America Inc
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Filing: 1984-11-28
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Granted: 1987-02-24
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Expires: 2004-11-28
Abstract
Abstract A flux gate sensor having sense windings for providing an output proportional to the strength of an external magnetic field in which the sensor is placed. A gating circuit which is responsive to a pulse which is generated when the core of the sensor is driven into and out of saturation gates the output of the sense windings to a pair of filters which in turn provide an output proportional to the intensity of the external magnetic field. With two sense windings the outputs of the filters may be used to determine the direction of the magnetic field relative to the sensor and thereby be used as a compass.
Inventors
- 👤 Alan C. Phillips
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 19:14
CPC Classifications
G; G01; G01R; G01R33/00; G01R33/02; G01R33/04
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
161 words
A flux gate sensor comprising: a saturable magnetic core; a drive winding wrapped about said core; a sense winding wrapped about said core; switching means coupled to said drive winding and a source of a predetermined potential for driving said core into saturation, said switching means including means responsive to a predetermined change in the magnitude of current in said drive winding when said core becomes saturated for driving said core out of saturation; a node located in said switching means having a potential which is driven toward said predetermined potential when said core is driven out of saturation; means coupled to said node which is responsive to said change in potential at said node when said core is driven out of saturation for providing a gate control signal having a predetermined period; and gating means coupled to said sense winding which is responsive to said gate control signal for providing an output from said sense winding during said predetermined period.
Claim 2
Dependent Claim
161 words
A flux gate sensor comprising: a saturable magnetic core; a drive winding wrapped about said core; a sense winding wrapped about said core; switching means coupled to said drive winding and a source of a predetermined potential for driving said core into saturation, said switching means including means responsive to a predetermined change in the magnitude of current in said drive winding when said core becomes saturated for driving said core out of saturation; a node located in said switching means having a potential which is driven toward said predetermined potential when said core is driven out of saturation; means coupled to said node which is responsive to said change in potential at said node when said core is driven out of saturation for providing a gate control signal having a predetermined period; and gating means coupled to said sense winding which is responsive to said gate control signal for providing an output from said sense winding during said predetermined period.
Claim 3
Dependent Claim
32 words
A sensor according to claim 1 wherein said switching means comprises a plurality of switching transistors and said node is located between said source of a predetermined potential and said switching transistors.
Claim 4
Dependent Claim
41 words
A sensor according to claim 2 wherein said switching means comprises a predetermined resistance coupled in series with said source of a predetermined potential and said switching transistors and said node is located between said predetermined resistance and said switching transistors.
Claim 5
Dependent Claim
22 words
A sensor according to claim 1 wherein said control signal providing means comprises means for providing a pulse having said predetermined period.
Claim 6
Dependent Claim
14 words
A sensor according to claim 4 wherein said predetermined period is approximately two microseconds.
Claim 7
Dependent Claim
42 words
A sensor according to claim 1 wherein said control signal providing means comprises means for providing said control signal in response to a change in the magnitude of the current in said drive winding when said core is driven out of saturation.
Claim 8
Dependent Claim
41 words
A sensor according to claim 6 wherein said control signal providing means comprises means for providing a pulse in response to a change in the magnitude of the current in said drive winding when said core is driven out of saturation.
Claim 9
Dependent Claim
28 words
A sensor according to claim 1 comprising filtering means and wherein said gating means comprises means for gating said output to said filtering means during said predetermined period.
Claim 10
Dependent Claim
14 words
A sensor according to claim 8 wherein said predetermined period is approximately two microseconds.
Claim 11
Dependent Claim
44 words
A sensor according to claim 8 for measuring the earth's magnetic field and wherein said filtering means comprises means responsive to said output of said gating means for providing a D.C. signal corresponding to said earth's magnetic field when said sensor is placed therein.
References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-02-23 | 1990-08-25 | 1991-02-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-02-23 | 1994-08-25 | 1995-02-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-02-23 | 1998-08-25 | 1999-02-24 | $7700.00 | Window Closed / Lapsed |