Electrical compass
First Claim
1. 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.
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Accused Products
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.
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Citations
16 Claims
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1. A control circuit for use with an electrically operated magnetic field detector employing a flux-gate sensor comprising:
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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. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A vehicle compass system comprising:
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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. - View Dependent Claims (8, 9, 10, 11)
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12. A control circuit for use with an electrically operated vehicle compass employing a flux-gate sensor comprising:
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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. - View Dependent Claims (13, 14, 15, 16)
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Specification