1
Steve W Bell, Robert L Breeden, Michael J Sabin: Touch sensitive screen signal detection arrangement. Bell Telephone Laboratories Incorporated, David H Tannenbaum, December 8, 1981: US04305071 (78 worldwide citation)

In certain situations it is necessary to detect a slight change in a continuous wave signal and to be able to specifically determine the exact position of the change. This is especially necessary in situations where a continuously changing signal (with respect to time) is generated and where it is n ...


2
Steve W Bell, Milton L Embree: Speakerphone linear comparator. AT&T Bell Laboratories, Frederick B Luludis, January 8, 1985: US04492824 (3 worldwide citation)

There is disclosed a precision linear comparator for a speakerphone circuit having two rectifying constant voltage nodes for separately summing two groups of signals derived from a speakerphone transmit channel and receive channel and supplying at an output terminal a signal representative of the di ...