The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 01, 1985
Filed:
May. 02, 1983
Applicant:
Inventor:
Eduard F Boeckman, Huntsville, AL (US);
Assignee:
GTE Business Communication Systems, Northlake, IL (US);
Attorneys:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H01M / ;
U.S. Cl.
CPC ...
179 / ; 179103 ;
Abstract
An amplifier for use with an electret microphone utilized as a telephone transmitter in a hand held telephone unit or handset. Incorporated into the circuitry is a band pass filter which substantially inhibits feedback 'singing' which occurs because of reflection when the handset or telephone unit is placed in a downward position on a hard surface or similar environment. The filter circuitry employs the source resistance of the telephone transmitter and the input resistance of a transistor amplifier stage as elements of the included filter circuitry.