Displacement detection apparatus including an error correction system
US5943639A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 19, 1995 |
| Grant date | Aug 24, 1999 |
| Priority date | — |
| Expiry date | Oct 19, 2015 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01D5/2449
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A displacement detecting apparatus includes an error correcting circuit through which a pair of sine wave signals detected by a detecting head unit are corrected. A signal detecting circuit receives the pair of sine wave signals whose phases are shifted by about 90.degree., and detects a magnitude of one of the two sine wave signal when the other one of the two sine wave signals crosses with a reference voltage level. The error correcting circuit calculates an error correction amount of each sine wave signal according to the detected magnitude of the signal and eliminates the calculated error correction amount from the signals. Therefore, the sine wave signals of position information are accurately corrected in direct-current component, voltage ratio and phase difference.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.