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US 4,366,467 AGranted
Torquer current readout system for inertial instrument employing current controlled oscillator
AssigneeNorthrop Corporation
InventorGlenn F. Cushman
Life of this patent
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AssigneeNorthrop Corporation
InventorGlenn F. Cushman
Estimating the term…
A system for converting analog torquer current to digital form is based on a current-controlled oscillator, preferably a YIG-tuned microwave oscillator, which produces an output frequency characterized by a nominally constant bias frequency term subject to drift and a tuning frequency term proportional to input current. An automatic calibration circuit gates the input current ON and OFF at a relatively low constant sampling rate. The number of cycles of the high frequency oscillator output is counted separately for the ON and OFF periods. The difference between the ON and OFF period counts is proportional to the input current and independent of the bias frequency. The system is specifically designed for converting analog torquer currents in inertial instruments to computer-compatible form.
In a readout system for an inertial instrument having a torquer coil for interacting magnetically with an inertial element when analog torquer current is passed through the coil, the improvement comprising means for measuring the current flowing through the torquer coil including:
In a readout system for an inertial instrument having opposed solenoid torquers for magnetically attracting the opposite sides of an inertial element, the improvement comprising means for measuring analog torquer currents through the respective solenoid torquers including:
In a readout system for an inertial instrument having opposed series-connected D'Arsonval torquer coils for interacting magnetically with an inertial element when analog torquer current is passed through the coils, the improvement comprising means for measuring the current flowing through the torquer coils including:
In a readout system for an inertial instrument having torquer coils aligned along at least one sense axis for interacting magnetically with an inertial element when analog torquer current is passed through one or more of said coils, the improvement comprising means for representing in digital form the amplitude of the current flowing through one or more of said torquer coils including:
Dependencies are inferred from the claim text.