Detector of passing magnetic articles with automatic gain control
US5694038A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 17, 1996 |
| Grant date | Dec 2, 1997 |
| Priority date | — |
| Expiry date | Jan 17, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03M1/303
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A magnetic-field-to-voltage transducer includes a Hall element and a digitally gain-controlled Hall-voltage amplifier that produces an analog voltage Vsig having excursions of one polarity corresponding to the passing of magnetic articles. Vsig is applied to the input of a signal-manipulating circuit that generates a proximity- detector binary output voltage, Vout, having transitions of one direction each time a predetermined point is reached in Vsig. A digitally gain-controlled gain amplifier is connected to the Hall element. A comparator circuit generates a binary signal Vbig (or V.sub.toobig) that changes from one to another binary level each time that Vsig exceeds a DC target voltage, V.sub.TG. The AGC circuit senses and counts gain counter excursions of one polarity in Vsig, and produces a binary count output signal at the input of the gain amplifier at each of the counted excursions in Vsig, incrementally changing the transducer gain in the direction to bring the peaks in Vsig to just below the target value T.sub.TG. This AGC feature prevents saturating the amplifier and quickly renders a Vsig of essentially constant amplitude so that either the peak excursion values or prede…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.