Metrological apparatus and calibration method therefor
US5150314A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 22, 1990 |
| Grant date | Sep 22, 1992 |
| Priority date | — |
| Expiry date | Jun 22, 2010 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B7/28
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A metrological apparatus for measuring form and texture of a surface employs an inductive transducer producing an AC gauge signal, and a tracking AC analogue to digital converter. In order to avoid errors in the output signal at a relatively high speed of traverse of the surface due to a non-flat frequency response of the converter, the output signal is processed by a digital filter to provide a combined frequency response which is flat over a desired range. In order to avoid errors in the output signal due to non-linearity of the transducer, a square or cubic correction is applied to the signal. A method calibrating the apparatus to obtain coefficients for the square and cube terms in the correction process is also described.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.