Circuit for producing pulses indicative of speed from a rotary generator without timing shift

US4487059A · kind A · utility

Assignee

• Robert Bosch GmbH · DE

Inventors

• Werner Fischer · Heimsheim, DE
• Helmut Kniss · Waiblingen, DE
• Johannes Locher · Stuttgart, DE

Key dates

• Filing date: Jun 15, 1983
• Grant date: Dec 11, 1984
• Expiry date: Jun 15, 2003

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y02T10/40
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

The Schmitt trigger threshold switch which produces rectangular waves in response to the output of a rotary ignition timing generator has a variable bias applied to its switch-in threshold which is proportional to the amplitude of the generator output, while the switch-out threshold remains fixed at or near zero voltage. The bias, which may be developed by a peak detector, prevents inherent ignition timing shift as the generator turns faster. The Schmitt trigger utilizes an inverting comparator so that a "lowest-wins" circuit can be used for applying stabilizing negative feedback or bias to the comparator. The bias provides immunity to disturbing voltages which increase with signal amplitude.