US4424631A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electrical compass
Assignee: Johnson Controls Technology Co
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Filing: 1982-03-02
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Granted: 1984-01-10
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Expires: 2002-03-02
Abstract
Abstract A magnetic field detecting system for use with a flux-gate sensor includes an oscillator, the output of which is applied to a digital bandpass filter and frequency divided and also applied to the sensor, and phase detectors such that the frequency and phase of the output signals from the flux-gate sensor have a predetermined relationship to the excitation signal. In one embodiment of the invention, the direction indicating output signals from the phase detectors are applied to a suitable interface circuit for a microprocessor which converts the signals to a digital format employed for application, to an alpha-type display for displaying the octal magnetic orientation of a vehicle.
Inventors
- 👤 Jeffrey L. Franks
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 03:13
CPC Classifications
G; G01; G01C; G01C17/00; G01C17/02; G01C17/28; G01C17/30
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
144 words
A control circuit for use with an electrically operated magnetic field detector employing a flux-gate sensor comprising: an oscillator for providing clock frequency output signals; counter means coupled to said oscillator and responsive to said clock frequency signals therefrom for providing an excitation frequency signal for a flux-gate sensor and for providing a synchronization signal at a harmonic frequency of said excitation frequency; bandpass filter means coupled to said oscillator and including means for receiving signal information from a flux-gate sensor and responsive to signal information and signals from said oscillator to provide signals at said harmonic frequency of said excitation frequency; and detection means coupled to said filter means and to said counter means and responsive to the synchronization signal and signals from said filter means for providing output signals representative of the orientation of a flux-gate sensor to an external magnetic field.
Claim 2
Dependent Claim
144 words
A control circuit for use with an electrically operated magnetic field detector employing a flux-gate sensor comprising: an oscillator for providing clock frequency output signals; counter means coupled to said oscillator and responsive to said clock frequency signals therefrom for providing an excitation frequency signal for a flux-gate sensor and for providing a synchronization signal at a harmonic frequency of said excitation frequency; bandpass filter means coupled to said oscillator and including means for receiving signal information from a flux-gate sensor and responsive to signal information and signals from said oscillator to provide signals at said harmonic frequency of said excitation frequency; and detection means coupled to said filter means and to said counter means and responsive to the synchronization signal and signals from said filter means for providing output signals representative of the orientation of a flux-gate sensor to an external magnetic field.
Claim 3
Dependent Claim
18 words
The circuit as defined in claim 1 wherein said bandpass filter means is a digital sampled data filter.
Claim 4
Dependent Claim
15 words
The circuit as defined in claim 2 wherein said harmonic frequency is the second harmonic.
Claim 5
Dependent Claim
50 words
The circuit as defined in claim 3 wherein said detection means includes digital phase detection means having a signal input coupled to the output of said bandpass filter and having clock input means coupled to said counter means for synchronizing the detection of signal information with said excitation frequency signal.
Claim 6
Dependent Claim
31 words
The circuit as defined in claim 4 wherein said detection means further includes integrating means having input means coupled to said phase detection means for providing an analog output signal therefrom.
Claim 7
Dependent Claim
28 words
The system as defined in claim 5 and further including circuit means coupled to said integrating means for providing a display of the orientation of a flux-gate sensor.
Claim 8
Dependent Claim
171 words
A vehicle compass system comprising: a flux-gate magnetic sensor having excitation input and signal output terminals; an oscillator for providing clock frequency output signals; counter means coupled to said oscillator and responsive to said clock frequency signals therefrom for providing an excitation frequency signal applied to said excitation input of said flux-gate sensor and for providing a synchronization signal at a harmonic frequency of said excitation frequency; bandpass filter means coupled to said oscillator and to said signal output terminals of said flux-gate sensor and responsive to signal information from said flux-gate sensor and signals from said oscillator to pass signals therethrough at said harmonic frequency of said excitation frequency; detection means coupled to said filter means and to said counter means and responsive to the synchronization signal and signals from said filter means for providing output signals representative of the orientation of a vehicle in which said flux-gate sensor is installed; and display means coupled to said detection means and responsive to said output signals for displaying the orientation information.
Claim 9
Dependent Claim
171 words
A vehicle compass system comprising: a flux-gate magnetic sensor having excitation input and signal output terminals; an oscillator for providing clock frequency output signals; counter means coupled to said oscillator and responsive to said clock frequency signals therefrom for providing an excitation frequency signal applied to said excitation input of said flux-gate sensor and for providing a synchronization signal at a harmonic frequency of said excitation frequency; bandpass filter means coupled to said oscillator and to said signal output terminals of said flux-gate sensor and responsive to signal information from said flux-gate sensor and signals from said oscillator to pass signals therethrough at said harmonic frequency of said excitation frequency; detection means coupled to said filter means and to said counter means and responsive to the synchronization signal and signals from said filter means for providing output signals representative of the orientation of a vehicle in which said flux-gate sensor is installed; and display means coupled to said detection means and responsive to said output signals for displaying the orientation information.
Claim 10
Dependent Claim
15 words
The circuit as defined in claim 7 wherein said harmonic frequency is the second harmonic.
Claim 11
Dependent Claim
18 words
The circuit as defined in claim 8 wherein said bandpass filter means is a digital sampled data filter.
Claim 12
Dependent Claim
50 words
The circuit as defined in claim 9 wherein said detection means includes digital phase detection means having a signal input coupled to the output of said bandpass filter and having clock input means coupled to said counter means for synchronizing the detection of signal information with said excitation frequency signal.
Claim 13
Dependent Claim
31 words
The circuit as defined in claim 10 wherein said detection means further includes integrating means having input means coupled to said phase detection means for providing an analog output signal therefrom.
Claim 14
Dependent Claim
150 words
A control circuit for use with an electrically operated vehicle compass employing a flux-gate sensor comprising: an oscillator for providing clock frequency output signals; counter means coupled to said oscillator and responsive to said clock frequency signals therefrom for providing an excitation frequency signal for a flux-gate sensor and for providing a synchronization signal at a harmonic frequency of said excitation frequency; digital sampled data bandpass filter means coupled to said oscillator and including means for receiving signal information from each signal output of a flux-gate sensor and responsive to signal information and signals from said oscillator to pass therethrough signals at substantially only said harmonic frequency of said excitation frequency; and digital phase detection means coupled to said filter means and to said counter means and responsive to the synchronization signal and signals from said filter means for providing output signals representative of the orientation of a flux-gate sensor.
Claim 15
Dependent Claim
150 words
A control circuit for use with an electrically operated vehicle compass employing a flux-gate sensor comprising: an oscillator for providing clock frequency output signals; counter means coupled to said oscillator and responsive to said clock frequency signals therefrom for providing an excitation frequency signal for a flux-gate sensor and for providing a synchronization signal at a harmonic frequency of said excitation frequency; digital sampled data bandpass filter means coupled to said oscillator and including means for receiving signal information from each signal output of a flux-gate sensor and responsive to signal information and signals from said oscillator to pass therethrough signals at substantially only said harmonic frequency of said excitation frequency; and digital phase detection means coupled to said filter means and to said counter means and responsive to the synchronization signal and signals from said filter means for providing output signals representative of the orientation of a flux-gate sensor.
Claim 16
Dependent Claim
15 words
The circuit as defined in claim 12 wherein said harmonic frequency is the second harmonic.
Claim 17
Dependent Claim
29 words
The circuit as defined in claim 13 and further including integrating means having input means coupled to said digital phase detection means for providing an analog output signal therefrom.
Claim 18
Dependent Claim
28 words
The system as defined in claim 14 and further including circuit means coupled to said integrating means for providing a display of the orientation of a flux-gate sensor.
Claim 19
Dependent Claim
15 words
The system as defined in claim 15 wherein said excitation frequency is about 400 Hz.
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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) | 1987-01-09 | 1987-07-11 | 1988-01-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-01-09 | 1991-07-11 | 1992-01-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-01-09 | 1995-07-11 | 1996-01-10 | $7700.00 | Window Closed / Lapsed |