Method and circuit arrangement for detecting short pulses of a digital input signal
AssigneeRobert Bosch GmbH
InventorWilhelm Hegeler
Life of this patent
Estimating the term…
Abstract
The detection of short pulses of a digital input signal by an evaluation circuit, whose time intervals for polling the input signal are long compared to the duration of the pulses, is made possible by the formation of a difference between the input signal and an output signal formed from the input signal. A change in the output signal is effected proportionally to the difference with a large proportionality factor when the difference has a first operational sign, and proportionally to the difference with a small proportionality factor when the difference has another operational sign.
Claims5
A method of detecting short pulses of a digital input signal by using time intervals of an evaluation circuit, each one of the time intervals having a duration that is long in comparison to a duration of a corresponding one of the short pulses, the method comprising the steps of:
- forming an output signal as a function of the digital input signal;
- forming a difference signal as a function of a difference between the digital input signal and the output signal;
- using a first proportionality factor when the difference signal has a first operational sign to effect a first change in the output signal that is proportionate to the difference signal;
- and
- using a second proportionality factor when the difference signal has a second operational sign to effect a second change in the output signal that is proportionate to the difference signal.
A circuit arrangement, comprising:
- an input for receiving an input signal;
- an output for providing an output signal;
- a subtraction stage having a first input for receiving the input signal and a second input for receiving the output signal delayed by one time pulse, the subtraction stage forming a difference signal that is a function of a difference between the input signal and the output signal delayed by one time pulse;
- a discriminator for assigning at least one of a first operational sign and a second operational sign to the difference signal;
- and
- a multiplication stage for forming at least one of a first proportionality factor and a second proportionality factor as a function of the difference signal in order to effect a change in the output signal that is proportional to the difference signal.
Dependencies are inferred from the claim text.