Signal processing apparatus and method
US6788221B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 24, 1998 |
| Grant date | Sep 7, 2004 |
| Priority date | — |
| Expiry date | Dec 24, 2018 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02P6/16
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Processing circuitry is provided for processing signals received from, for example, sense coils forming part of a position encoder used to encode the relative positions of two relatively moveable members. The position encoder is such that each of the plurality of signals from the sense coils varies sinusoidally with the relative position of the members but out of phase with respect to each other. The processing circuitry comprises mixers for multiplying each of the received signals with one of a corresponding plurality of periodic time varying signals, each having the same predetermined period and a different predetermined phase, and an adder for adding the signals from the mixers. The phase of the mixing signals are chosen so that the output signals from the adder contains a single periodic component having the predetermined period whose phase varies with the relative position of the two members. Preferably, a reference channel is provided in order to allow for compensation of common phase errors in both channels. The period time varying signals multiplied with each of the signals from the position encoder preferably comprise a two or three level square wave signal having a number…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.