Differential threshold detector
First Claim
1. An adaptive reference threshold detector for sensing a drop of predetermined magnitude in the level of an input signal from its peak value during an interval of time comprising:
- a voltage follower circuit including an operational amplifier having a positive input port coupled to said input signal and an output coupled through a diode to a capacitor, whereby said capacitor charges to the maximum voltage level at the output of said voltage follower circuit and thereby establishes a reference voltage derived from said input signal in cooperation with said voltage follower;
an FET device having its gate coupled to said capacitor and its source coupled to the negative input port of said voltage follower circuit operational amplifier in a manner such that negative feedback is applied thereto; and
a comparator circuit having a positive input port coupled to said input signal and a negative input port coupled to the source of said FET device through a resistive divider, thereby continuously comparing said input signal with said reference level and producing a logic level output signal whenever the difference in magnitude between said input signal and said reference level exceeds a preselected value.
0 Assignments
0 Petitions
Accused Products
Abstract
An adaptive reference threshold detector for sensing a drop of predetermined magnitude in the level of an input signal from its peak value during an interval of time. A capacitor, diode coupled to the output of a voltage follower, is charged to a level coincident with the maximum input signal voltage during the time interval of interest. The voltage stored thereon is coupled through a negative feedback arrangement and resistive divider network to one port of a voltage comparator. The input signal itself serves as the second input to this voltage comparator circuit. A logic level signal is generated by this comparator when the difference between its two input port signals exceeds a predetermined value.
-
Citations
2 Claims
-
1. An adaptive reference threshold detector for sensing a drop of predetermined magnitude in the level of an input signal from its peak value during an interval of time comprising:
-
a voltage follower circuit including an operational amplifier having a positive input port coupled to said input signal and an output coupled through a diode to a capacitor, whereby said capacitor charges to the maximum voltage level at the output of said voltage follower circuit and thereby establishes a reference voltage derived from said input signal in cooperation with said voltage follower; an FET device having its gate coupled to said capacitor and its source coupled to the negative input port of said voltage follower circuit operational amplifier in a manner such that negative feedback is applied thereto; and a comparator circuit having a positive input port coupled to said input signal and a negative input port coupled to the source of said FET device through a resistive divider, thereby continuously comparing said input signal with said reference level and producing a logic level output signal whenever the difference in magnitude between said input signal and said reference level exceeds a preselected value. - View Dependent Claims (2)
-
Specification