Browse Prior Art Database

Threshold Detector

IP.com Disclosure Number: IPCOM000093136D
Original Publication Date: 1967-May-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 2 page(s) / 35K

Publishing Venue

IBM

Related People

Simpson, RA: AUTHOR

Abstract

This detector provides an output pulse on.terminal 10 whenever a positive input signal, applied at terminal 11, exceeds a predetermined threshold. The detector includes a first amplification stage including transistor T1 that provides the desired input impedance and allows gain adjustment to the desired level through potentiometer 12. The amplified positive output from T1 is supplied to a second amplifier including transistor T2. The latter provides the desired output phase and permits adjustment of the DC level of the signal by potentiometer 13.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 96% of the total text.

Page 1 of 2

Threshold Detector

This detector provides an output pulse on.terminal 10 whenever a positive input signal, applied at terminal 11, exceeds a predetermined threshold. The detector includes a first amplification stage including transistor T1 that provides the desired input impedance and allows gain adjustment to the desired level through potentiometer 12. The amplified positive output from T1 is supplied to a second amplifier including transistor T2. The latter provides the desired output phase and permits adjustment of the DC level of the signal by potentiometer 13.

Diode 14, connected to the collector of T2, provides a clipping function and limits the signal supply to transistor T3 within the usable range. T3 isolates the first two amplification stages from the output switching stages. Transistor T4, which receives its input from the emitter of T3, is turned on in response to operation of T3 and it turns T5 off rapidly to provide a good square output.

The emitter of T4 is connected to reference voltage Vref which can be adjusted to control the shape of the pulse provided from T5.

This circuit provides advantages over the commonly used voltage comparator-type threshold circuits in that it is not amplitude sensitive and it has a wide frequency range. It is particularly useful in applications where high- resolution pulses are required to indicate the attainment of a predetermined threshold by a varying input signal that covers wide frequency and amplitude ranges.

1

...