Analog signal processing circuit with noise immunity and reduced delay
AssigneeGeneral Electronics Applications, Inc.
InventorJoseph Pernyeszi
Life of this patent
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Abstract
An improved pulse detection circuit provides for a reduced delay response and noise immunity. The pulse detection circuit includes a comparator with a hysteresis circuit providing a hysteresis response on the order of a minimum pulse width and a reference circuit having a time constant which is a function of unexpected signal input level.
Claims15
A pulse detection circuit for filtering a pulse signal with noise superimposed thereon into a digital bi-level signal representing the pulse signal, wherein the pulse signal comprising predetermined signal criteria, the circuit comprising:
- a comparator, coupled at a comparator output to an output of the pulse detection circuit, wherein the output of the comparator is a high signal when a first input voltage at a positive comparator input is higher than a second input voltage at a negative comparator input and wherein the output of the comparator is a low signal when the first input voltage is lower than the second input voltage;
- a hysteresis circuit comprising a first impedance circuit coupled between the positive comparator input and the comparator output and a second impedance circuit coupled between an input node having thereon an input signal representing the pulse signal and the positive comparator input, wherein the hysteresis circuit is characterized by a first time constant having a value that is a first function of at least a first criteria of the predetermined signal criteria;
- and
- a reference circuit comprising a third impedance circuit coupled between the negative comparator input and ground and a fourth impedance circuit coupled between the comparator output and the negative comparator input, wherein the reference circuit is characterized by a second time constant having a value that is a second function of at least a second criteria of the predetermined signal criteria.
A pulse detection circuit for filtering a pulse signal with noise superimposed thereon into a digital bi-level signal representing the pulse-signal, wherein the pulse signal comprising predetermined signal criteria, the circuit comprising:
- a comparator, coupled at a comparator output to an output of the pulse detection circuit, wherein the output of the comparator is a high signal when a first input voltage at a positive comparator input is higher than a second input voltage at a negative comparator input and wherein the output of the comparator is a low signal when the first input voltage is lower than the second input voltage;
- a hysteresis resistor-capacitor circuit comprising a capacitor coupled between the positive comparator input and the comparator output and a resistor coupled between an input node having thereon an input signal representing the pulse signal and the positive comparator input, wherein the hysteresis resistor-capacitor circuit is characterized by a first time constant having a value that is a first function of at least a first criteria of the predetermined signal criteria;
- and
- a reference resistor-capacitor circuit comprising a capacitor coupled between the negative comparator input and ground and a resistor coupled between the comparator output and the negative comparator input, wherein the reference resistor-capacitor circuit is characterized by a second time constant having a value that is a second function of at least a second criteria of the predetermined signal criteria.
In a pulse detector, a method of detecting signal transitions in an input signal which is a binary data stream with noise superimposed thereon to form an output signal having transitions in correspondence with the signal transitions, the method comprising the steps of:
- providing the input signal to a first input of a comparing means;
- providing hysteresis between said first input and an output of said comparing means, said hysteresis characterized by a first time constant, wherein said first time constant has a value that is a function of at least a first criteria of the input signal;
- providing a reference circuit between said output of said comparing means and a second input, said reference circuit characterized by a second time constant, wherein said second time constant has a value that is a function of at least a second criteria of the input signal.
Dependencies are inferred from the claim text.