United Technologies Corporation

Timothy F Stack

George T Shoemaker

Richard W Calcasola

James P Ericksen

A conventional regenerative comparator is modified by including a transistor switch in the feedback network to open circuit the feedback path according to the output state of the comparator, and by biasing the noninverting input of the comparator with a voltage directly proportional to the amplitude of the input signal, thereby providing variable threshold comparator with a hysteresis transfer characteristic with two distinct state change threshold levels that are a fixed ratio of the amplitude of the input signal.

Differential receiver with self-adaptive hysteresis

A synchro signal-to-digital signal converter for providing a digital signal representation of synchro angle value in response to sensed synchro signals representative of actual synchro stator voltage signals and actual synchro rotor voltage signals, includes an analog signal interface responsive to the sensed synchro signals for providing a digital signal representative of the ratio of the smaller of the difference signal magnitudes between each of two stator winding voltage signals and a third stator winding voltage signal selected as a reference, divided by the larger, and for providing discrete signal manifestations of the particular one of a plurality of successive ranges of synchro angle values associated with the sensed synchro signals received, the synchro to digital signal converter further including a signal processor responsive to the digital ratio signal and to the discrete signal manifestations of synchro angle range, for providing a signal representation of actual synchro angle value associated with the sensed synchro signal data received.

AC Synchro signal to digital signal converter

A universal analog signal interface includes a pair of signal conditioning circuits, each responsive to one of a pair of analog signals presented between two inputs of each for providing corresponding pairs of output signal manifestations representative of the magnitude and the phase of the pair of signals received; the analog interface further including signal conversion circuitry responsive to each of the pairs of signal manifestations of magnitude and phase for providing a digital signal representative of the ratio of the smaller magnitude signal manifestation divided by the larger magnitude signal manifestation and for providing digital signals representative of each of the phase signal manifestations.

Universal analog signal to digital signal interface

An RTD probe interface having a three-wire interconnection with a source excitation line, a source return line, and a sensed signal line, includes: an excitation signal source connected between the source excitation line and the source return line for providing an excitation current signal through the RTD; an amplifier having first and second signal inputs connected respectively to the source excitation line and the sensed signal line, for providing an output voltage signal at a magnitude proportional to the difference magnitude between the voltage signals present at the first and second amplifier inputs, and a bias signal source connected between the sensed signal line and the source return line for presenting a bias current signal to the sensed line, at a magnitude and phase equal to that of the excitation current signal, for providing equal line impedance dependent values in the voltage signals appearing at the first and second inputs of the amplifier.

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Enfield, CT, United States of America

Timothy F Stack