Adaptive threshold circuit
US5459398A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 17, 1993 |
| Grant date | Oct 17, 1995 |
| Priority date | — |
| Expiry date | Dec 17, 2013 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01P3/489
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An adaptive threshold circuit for use with a magnetic type of sensor that has a pick-up coil. The pick-up coil has an alternating voltage induced therein when a slot formed in a wheel rotates past the sensor. The circuit produces a square wave pulse voltage during positive half-cycles of the voltage generated in the pick-up coil. The circuit includes a digital to analog converter the input of which is connected to a pulse counter. The output of the converter is a function of the count magnitude in the counter and provides a variable threshold voltage that is compared by a voltage comparator with a voltage that is a function of the magnitude of the voltage generated in the pick-up coil. The circuit has an input circuit connected to the pick-up coil that includes a voltage attenuating circuit and a diode. The pulse count of the counter is, at times, incremented under control of a comparator that compares the output voltage of the converter with a voltage that is a function of the magnitude of the voltage generated in the pick-up coil.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.