Method of noise rejection in a magnetostrictive position detector including determining a valid time range for propagation of sonic pulses over a reference distance
US5258707A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 20, 1992 |
| Grant date | Nov 2, 1993 |
| Priority date | — |
| Expiry date | Jul 20, 2012 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B7/02
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A position detection probe having a magnetostrictive wire stretched between a head and a reflective foot end termination, and a magnet movable along the probe uses the sonic pulse propagation time from the magnet to the head as one parameter and the time from the magnet to the foot and reflected back to the head as another parameter for determining the magnet position. The sum of the propagation times is a constant which is used as a reference value. Upon receipt of the first two pulses the propagation times are summed and compared to the reference value, and the data is accepted if the sum is within a prescribed window around the reference value. When noise occurs, it creates a false measure of propagation time so that the sum of the propagation times is no longer equal to the reference value and the data is rejected.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.