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US 5,766,137 AGranted
Frequency deviation detecting circuit and measuring apparatus using the frequency deviation detecting circuit
AssigneeAxiom
InventorSadao Omata
Life of this patent
Estimating the term…
Abstract
A hardness measuring apparatus in which a frequency deviation detecting circuit is used has a contact element, an oscillator, a self-oscillating circuit and a gain variation compensating circuit. The self-oscillating circuit feeds back oscillation information of the oscillator to generate a resonant state. The gain variation compensating circuit is disposed in the self-oscillating circuit. The gain variation compensating circuit has a central frequency different from that of the self-oscillating circuit, and increases gain in response to a change in frequency.
Claims26
A frequency deviation detecting circuit comprising:
- an oscillator for generating a mechanical oscillation;
- a self-oscillating circuit for feeding back oscillation information of the oscillator, and for generating a resonant state in the oscillator, wherein the oscillator and the self-oscillating circuit form an electromechanical oscillation system;
- and
- a gain variation compensating circuit which is disposed in the self-oscillating circuit, has a central frequency different from that of the self-oscillating circuit, and increases gain of the self-oscillating circuit in response to a change in frequency of the electromechanical oscillation system;
- wherein the effective resonance frequency band of the electromechanical oscillation system is expanded.
2 more elements
A hardness measuring apparatus for obtaining hardness information of a subject comprising:
- a contact element adapted to contact a subject;
- an oscillator for oscillating the contact element;
- a self-oscillating circuit which feeds back oscillation information of the oscillator oscillating the contact element in contact with the subject to generate a resonant state in the oscillator, wherein the oscillator and the self-oscillating circuit form an electromechanical oscillation system;
- and
- a gain variation compensating circuit which is disposed in the self-oscillating circuit, has a central frequency different from that of the self-oscillating circuit, and increases gain of the self-oscillating circuit in response to a change in frequency of the electromechanical oscillation system;
- wherein the effective resonance frequency band of the electromechanical oscillation system is expanded.
3 more elements
A hardness measuring apparatus for obtaining hardness information of a subject comprising:
- a contact element in contact with a subject;
- an oscillator for oscillating the contact element;
- a self-oscillating circuit which feeds back oscillation information of the oscillator oscillating the contact element in contact with the subject to generate a resonant state in the oscillator, wherein the oscillator and the self-oscillating circuit form an electromechanical oscillation system;
- a gain variation compensating circuit which is disposed in the self-oscillating circuit, has a central frequency different from that of the self-oscillating circuit, and increases gain in response to a change in frequency of the electromechanical oscillation system;
- and
- a frequency measuring circuit for detecting a change in the frequency of the electromechanical oscillation system.
3 more elements
A hardness measuring apparatus for obtaining hardness information of a subject comprising:
- a contact element adapted to contact a subject;
- an oscillator for oscillating the contact element;
- a phase lock loop circuit which feeds back oscillation information of the oscillator oscillating the contact element in contact with the subject to generate a resonant state in the oscillator, wherein the contact element, the oscillator and the phase lock loop circuit form an electromechanical oscillation system;
- and
- a gain variation compensating circuit which is disposed in the phase lock loop circuit, has a central frequency different from that of the phase lock loop circuit, and increases gain of the phase lock loop circuit in response to a change in frequency of the electromechanical oscillation system;
- wherein the effective resonance frequency band of the electromechanical oscillation system is expanded.
3 more elements
An acceleration measuring apparatus for measuring a change in the acceleration of a moving substance comprising:
- an oscillator which is placed on the moving substance, and generates a mechanical oscillation;
- a self-oscillating circuit which feeds back oscillation information of the oscillator to generate a resonant state in the oscillator, wherein the oscillator and the self-oscillating circuit form an electromechanical oscillation system;
- and
- a gain variation compensating circuit which is disposed in the self-oscillating circuit, has a central frequency different from that of the self-oscillating circuit, and increases gain of the self-oscillating circuit in response to a change in frequency of the electromechanical oscillation system;
- wherein the effective resonance frequency band of the electromechanical oscillation system is expanded.
2 more elements
A fluid viscosity measuring apparatus for measuring a change in the viscosity of a fluid comprising:
- any of an oscillator for generating oscillation in a fluid and an oscillator for oscillating a fluid contacting element put in the fluid;
- a self-oscillating circuit which feeds back oscillation information of the oscillator to generate a resonant state in the oscillator, wherein the oscillator and the self-oscillating circuit form an electromechanical oscillation system;
- and
- a gain variation compensating circuit which is disposed in the self-oscillating circuit, has a central frequency different from that of the self-oscillating circuit, and increases gain of the self-oscillating circuit in response to a change in frequency of the electromechanical oscillation system;
- wherein the effective resonance frequency band of the electromechanical oscillation system is expanded.
2 more elements
A fluid pressure measuring apparatus for measuring a change in the pressure of a fluid comprising:
- a fluid contacting element whose shape is changed in response to the pressure of a fluid;
- an oscillator which generates oscillation, and the position of which is moved in response to the change in the pressure of the fluid;
- a self-oscillating circuit which feeds back oscillation information of the oscillator to generate a resonant state in the oscillator, wherein the oscillator and the self-oscillating circuit form an electromechanical oscillation system;
- and
- a gain variation compensating circuit which is disposed in the self-oscillating circuit, has a central frequency different from that of the self-oscillating circuit, and increases gain of the self-oscillating circuit in response to a change in frequency of the electromechanical oscillation system,
- wherein the effective resonance frequency band of the electromechanical oscillation system is expanded.
3 more elements
Dependencies are inferred from the claim text.