Simplified monitoring apparatus for sensors in motor vehicles

US4408289A · kind A · utility

Assignee

• Robert Bosch GmbH · DE

Inventors

• Bernward Boning · Ludwigsburg, DE
• Rainer Bone · Leinfelden, DE
• Rudolf Nagel · Asperg, DE
• Jens-Detlef Rubrecht · Braunschweig, DE

Key dates

• Filing date: Dec 22, 1980
• Grant date: Oct 4, 1983
• Expiry date: Dec 22, 2000

Classification

• Technology area (CPC G): Physics
• CPC primary: G01R23/15
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

The leading edge of each pulse of an incoming signal sequence starts a first monostable multivibrator whose period is equal to the period of the pulse sequence when the pulse sequence has the desired frequency. The input signal sequence and the output signal from the multivibrator are applied to two inputs of an exclusive OR gate. The latter furnishes an output signal corresponding to the difference in pulse width between the signal applied to the two inputs. The leading edge of the difference signal then starts a second monostable multivibrator whose pulse width corresponds to the maximum allowable frequency deviation. The output signal of the second monostable multivibrator is applied to an inverting input of an AND gate. The direct input of the AND gate receives the difference signal. The AND gate, therefore, only furnishes an output signal when the difference signal has a greater pulse width than the output signal of the second multivibrator, i.e. when the frequency deviation in the incoming signal sequence exceeds the maximum permissible frequency deviation.