Browse Prior Art Database

Edge Detection Using Delayed Feedback on Inverting Amplifier

IP.com Disclosure Number: IPCOM000061210D
Original Publication Date: 1986-Jul-01
Included in the Prior Art Database: 2005-Mar-09
Document File: 2 page(s) / 29K

Publishing Venue

IBM

Related People

Marple, WP: AUTHOR

Abstract

An edge detector is disclosed which employs an operational amplifier having its negative input terminal connected to the input voltage source and its positive input terminal connected to ground potential. Its output terminal is connected through a feedback delay element to its negative input terminal. The waveform A is the input waveform whose rising edge and falling edge are to be detected. The waveform B is the output Vout of the amplifier, indicating the positive-going or negative-going edge which is detected by the circuit. In operation, a positive-going signal input to the amplifier is fed back through the delay element to the input so that the duration of the output signal Vout (waveform B) is equal to the delay duration of the delay element.

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Edge Detection Using Delayed Feedback on Inverting Amplifier

An edge detector is disclosed which employs an operational amplifier having its negative input terminal connected to the input voltage source and its positive input terminal connected to ground potential. Its output terminal is connected through a feedback delay element to its negative input terminal. The waveform A is the input waveform whose rising edge and falling edge are to be detected. The waveform B is the output Vout of the amplifier, indicating the positive-going or negative-going edge which is detected by the circuit. In operation, a positive- going signal input to the amplifier is fed back through the delay element to the input so that the duration of the output signal Vout (waveform B) is equal to the delay duration of the delay element. When the positive going input waveform is fed back to the input of the amplifier, it results in turning off the output, thereby terminating the duration of the edge-detected waveform B. The delay element delta T can be a lumped element delay line, a piece of coax, or any other conventional delay line mechanism. The values of the input resistor R1 and the feedback resistor RF can be adjusted to conform with the desired input and output voltage magnitudes.

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