Circuit system for preventing measuring device from being erroneously operated
US5128973A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 23, 1990 |
| Grant date | Jul 7, 1992 |
| Priority date | — |
| Expiry date | Oct 23, 2010 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03K5/1252
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A circuit system for preventing a measuring device such as an engine speed measuring device or the like from being erroneously operated includes as essential components a filter circuit, a Schmitt trigger circuit, an oscillating circuit, a counting circuit, a pulse monitoring circuit and an adding circuit. A combination of the filter circuit and the Schmitt trigger circuit serve to properly shape a wave form of each of a series of pulse-shaped sensor detection signals. The oscillating circuit generates a series of pulses each having a reference frequency. The pulse monitoring circuit monitors a wave-form shaping output pulse by counting the number of a series of output pulses each having a reference frequency for a predetermined period of time with the edge of the wave-form shaping output pulse as a trigger. In addition, the pulse monitoring circuit serves to discriminate whether a bound is caused in the wave-form shaping output signal or not and then deliver a processing signal to a processing circuit at the next stage. The circuit system has a diverging point which is located between the Schmitt circuit and the counting circuit so that a series of pulse-shaped sensor detecting si…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.