Method of generating an index signal for an optical encoder
US7075057B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 26, 2005 |
| Grant date | Jul 11, 2006 |
| Priority date | — |
| Expiry date | Apr 26, 2025 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N7/185
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A processing apparatus calculates and applies calibrations to sensors that produce quasi-sinusoidal, quadrature signals, using fixed or programmable electronic circuits, a circuit to calculate the phase and magnitude corresponding to the two input (quadrature) signals, and a circuit for accumulating the number of cycles of the input signals. The apparatus also includes a circuit to generate Gain, Offset, and Phase calibration coefficients by comparing a phase space position of a measured phasor with the position of an idealized phasor whose locus in phase space is a circle of predetermined radius with no offset. The calculation of the coefficients occurs without user intervention, according to a pre-programmed rule or rules. The apparatus also includes a circuit to apply the Gain, Offset, and Phase calibration coefficients to the measured quadrature signals xi and yi according to predetermined formulae using scaling coefficients, offset coefficients and a phase coefficient.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.