Systems for measuring physical quantities
AssigneesNGK Insulators, Ltd., Seiko Epson Corporation, Seiko NPC Corporation
InventorsShoji Yokoi, Yoshihiro Kobayashi, Masayuki Takahashi
Life of this patent
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Abstract
It is provided a system for measuring a physical quantity based on a detection signal using a vibrator 1, a self-oscillating circuit 12A oscillating a driving vibration in the vibrator 1 and a detection circuit for outputting a detection signal from the vibrator 1. The self-oscillating circuit 12A comprises a current-voltage converter 3 and a low pass filter 25. The detection circuit comprises a charge amplifier circuit amplifying an output signal from the vibrator, and the current-voltage converter and the charge amplifier circuit are formed in a monolithic IC.
Claims4
A system of measuring a physical quantity based on a detection signal using a vibrator, a self-oscillating circuit oscillating a driving vibration in said vibrator and a detection circuit for outputting a detection signal from said vibrator,
- wherein said self-oscillating circuit comprises a current/voltage converter that converts an alternating current to a voltage, and a low pass filter comprising a resistance and a condenser, said low pass filter having an amplification factor having a proportionality factor of 0.9 or larger and 1.1 or smaller with respect to (1/R1·C1), C1 representing a capacitance of said condenser of said low pass filter and R1 representing a resistance value of said resistance of said low pass filter;
- wherein said detection circuit comprises a charge amplifier circuit amplifying an output signal from said vibrator;
- and
- wherein said current-voltage converter and said charge amplifier circuit are formed in a monolithic IC.
A system of measuring a physical quantity based on a detection signal using a vibrator, a self-oscillating circuit oscillating a driving vibration in said vibrator and a detection circuit for outputting a detection signal from said vibrator,
- wherein said self-oscillating circuit comprises a current/voltage converter that converts an alternating current to a voltage, and a low pass filter;
- wherein said detection circuit comprises a charge amplifier circuit amplifying an output signal from said vibrator;
- wherein said current-voltage converter and said charge amplifier circuit are formed in a monolithic IC;
- and
- wherein ω is 5 times or larger of ω0,ω representing an angular frequency of an input signal, and ω0 representing a characteristic angular frequency of said low pass filter.
A system of measuring a physical quantity based on a detection signal using a vibrator, a self-oscillating circuit oscillating a driving vibration in said vibrator and a detection circuit for outputting a detection signal from said vibrator,
- wherein said self-oscillating circuit comprises a current/voltage converter that converts an alternating current to a voltage, and a low pass filter comprising a resistance and a condenser, a measured current value in said self-oscillating circuit being substantially proportional to (1/C1), C1 representing a capacitance of said condenser of said low pass filter;
- wherein said detection circuit comprises a charge amplifier circuit amplifying an output signal from said vibrator;
- and
- wherein said current-voltage converter and said charge amplifier circuit are formed in a monolithic IC.
Dependencies are inferred from the claim text.