Adaptive threshold circuit with deceleration compensation
US5554948A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 31, 1994 |
| Grant date | Sep 10, 1996 |
| Priority date | — |
| Expiry date | May 31, 2014 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03K5/086
- 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 or tooth 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 selectable pulse counter. The pulse counter has a decrement function that allows for the count to be varied so as to accommodate sudden wheel decelerations. According to one embodiment, the counter may down count to reduce the count number. In accordance with a second embodiment, the counter may shift out one bit to perform a divide-by-two operation on the count number. 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…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.