Robert D Potter

US Patent:

7092538, Aug 15, 2006

Filed:

Apr 11, 2003

Appl. No.:

10/412460

Inventors:

Robert C. Potter - Naperville IL, US
Steven E. Boor - Plano TX, US

Assignee:

Knowles Electronics, LLC - Itasca IL

International Classification:

H04R 3/00

US Classification:

381113, 381317, 330 9, 327124

Abstract:

A method and apparatus for substantially reducing and virtually eliminating direct current flow through the input transistor(s) of an input buffer circuit for an electret microphone is disclosed. An input transistor is provided and operably connected to an input and an output of the input buffer circuit. The input transistor has a first operating state wherein current flow occurs in a first direction and a second operating state wherein the a current flow occurs in a second direction—opposite that of the first direction. The input transistor is biased to alternately control operation between the first operating state and the second operating state. The alternating, opposing flows of current of the respective operating states cooperate to substantially reduce and virtually eliminate the flow of direct current through the input transistor(s) of the buffer circuit. A reduction in excess noise associated with the input transistor results from the substantially decreased direct current flow through the input transistor(s) of the buffer circuit.

US Patent:

46776095, Jun 30, 1987

Filed:

May 8, 1985

Appl. No.:

6/731885

Inventors:

Richard J. Piereth - Naperville IL
Robert L. Potter - Naperville IL
John R. Williams - Naperville IL

Assignee:

American Telephone and Telegraph Company, AT&T Bell Laboratories - Murray Hill NJ

International Classification:

H04Q 1104

US Classification:

370 60

Abstract:

A semi-automatic directory assistance system uses a directory assistance computer to help an operator at an operator position terminal find the requested directory number. The control processor, a module control unit, of a module of the system controls the establishment of part of the connection from a subscriber requesting operator assistance to the operator position. The operator at the operator position communicates with the directory assistance computer to find the requested number. After the requested number has been found, the computer sends a message to the control processor. In response to that message, the control processor causes an audio response unit to generate a directory assistance message corresponding to the desired number and causes the response unit to be connected to the subscriber.