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US 4,482,859 AGranted
Object displacement sensor and device for measuring the rotation speed and vibration frequency of a rotor
AssigneeSnecma
InventorJacques M. A. Fournier
Life of this patent
Estimating the term…
Abstract
An object displacement sensor specifically adapted for high speed counting of passing nonmagnetic objects is disclosed which has a resonant circuit made up of at least one inductive element 2 and a condensor whose one plate consists of a conductive surface 3 and whose other plate is successively formed by each object 4 passing close to this surface 3. The resonant circuit is connected to a first oscillator 6 which determines the functioning frequency such that the signal issued from the first oscillator 6 is modulated in frequency to the rhythm of the passage of the objects 4.
Claims9
An object displacement sensor comprising:
- a resonant circuit having at least one inductive element and a condensor with one of the plates of said condensor being made up of a conductive surface and the other plate being successively formed by each one of a plurality of objects passing close to said surface;
- a first oscillator connected to said resonant circuit for determining a functioning frequency such that the signal issued from said first oscillator is modulated by the frequency with which said objects pass said surface;
- frequency discriminator means comprising a second oscillator controlled by a phase loop consisting of a first multiplier circuit and a first integrator with the reference input of said first multiplier circuit being supplied with the frequency modulated signal issued from said first oscillator in order to provide a demodulation of said frequency modulation signal issued by said first oscillator.
Dependencies are inferred from the claim text.