Pressure measuring device and method using quartz resonators
US5546810A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 3, 1995 |
| Grant date | Aug 20, 1996 |
| Priority date | — |
| Expiry date | May 3, 2015 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01L9/0022
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
The temperature dependence of the difference in oscillation frequency between two quartz resonators caused by the pressure difference between the two quartz resonators as well as the intrinsic physical properties between them can be compensated accurately and at low cost by calibrating the difference in oscillation frequency between the two quartz resonators by means of a quadratic formula with regard to temperature or by reducing the temperature dependence of the difference in oscillation frequency by connecting a thermistor to oscillation circuits. Pulses from each of an oscillation circuit (1) including a quartz resonator placed in vacuum and another oscillation circuit (2) including a quartz resonator placed in an atmospheric pressure are counted by pulse counters (3, 4). The difference between the pulse counts is obtained by a subtracter (5) and sent out to an MPU (6) as a measured value. A temperature sensor (7) measures the ambient temperature of both the quartz resonators and outputs it to MPU (6) through an AD converter (8). MPU (6) determines a quadratic temperature calibration formula with regard to temperature using the input temperature data and the calibration paramet…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.